diff --git a/src/builtins.ts b/src/builtins.ts
index 4e98301230..8e0f3c4736 100644
--- a/src/builtins.ts
+++ b/src/builtins.ts
@@ -2170,7 +2170,7 @@ export function compileCall(
       }
 
       // otherwise call abort if the assertion is false-ish
-      let abort = compileAbort(compiler, operands.length == 2 ? operands[1] : null, reportNode);
+      let abort = compiler.makeAbort(operands.length == 2 ? operands[1] : null, reportNode);
       compiler.currentType = type.nonNullableType;
       if (contextualType == Type.void) { // simplify if dropped anyway
         compiler.currentType = Type.void;
@@ -4726,49 +4726,6 @@ function deferASM(
   );
 }
 
-/** Compiles an abort wired to the conditionally imported 'abort' function. */
-export function compileAbort(
-  compiler: Compiler,
-  message: Expression | null,
-  reportNode: Node
-): ExpressionRef {
-  var program = compiler.program;
-  var module = compiler.module;
-
-  var stringInstance = compiler.program.stringInstance;
-  if (!stringInstance) return module.unreachable();
-
-  var abortInstance = program.abortInstance;
-  if (!(abortInstance && compiler.compileFunction(abortInstance))) return module.unreachable();
-
-  var messageArg: ExpressionRef;
-  if (message !== null) {
-    // The message argument works much like an arm of an IF that does not become executed if the
-    // assertion succeeds respectively is only being computed if the program actually crashes.
-    // Hence, let's make it so that the autorelease is skipped at the end of the current block,
-    // essentially ignoring the message GC-wise. Doesn't matter anyway on a crash.
-    messageArg = compiler.compileExpression(message, stringInstance.type, Constraints.CONV_IMPLICIT | Constraints.WILL_RETAIN);
-  } else {
-    messageArg = compiler.makeZero(stringInstance.type);
-  }
-
-  var filenameArg = compiler.ensureStaticString(reportNode.range.source.normalizedPath);
-
-  compiler.currentType = Type.void;
-  return module.block(null, [
-    module.call(
-      abortInstance.internalName, [
-        messageArg,
-        filenameArg,
-        module.i32(reportNode.range.line),
-        module.i32(reportNode.range.column)
-      ],
-      NativeType.None
-    ),
-    module.unreachable()
-  ]);
-}
-
 /** Compiles the `visit_globals` function. */
 export function compileVisitGlobals(compiler: Compiler): void {
   var module = compiler.module;
diff --git a/src/compiler.ts b/src/compiler.ts
index 2c68a86340..1e81094c4e 100644
--- a/src/compiler.ts
+++ b/src/compiler.ts
@@ -6,7 +6,6 @@
 import {
   BuiltinNames,
   compileCall as compileBuiltinCall,
-  compileAbort,
   compileVisitGlobals,
   compileVisitMembers,
   compileRTTI,
@@ -2499,7 +2498,9 @@ export class Compiler extends DiagnosticEmitter {
       let newArgs = (<NewExpression>value).arguments;
       if (newArgs.length) message = newArgs[0]; // FIXME: naively assumes type string
     }
-    stmts.push(compileAbort(this, message, statement));
+    stmts.push(
+      this.makeAbort(message, statement)
+    );
 
     return this.module.flatten(stmts);
   }
@@ -3125,21 +3126,48 @@ export class Compiler extends DiagnosticEmitter {
     // any to void
     if (toType.kind == TypeKind.VOID) return module.drop(expr);
 
-    if (this.currentFlow.isNonnull(expr, fromType)) fromType = fromType.nonNullableType;
+    // reference involved
+    if (fromType.is(TypeFlags.REFERENCE) || toType.is(TypeFlags.REFERENCE)) {
+      if (this.currentFlow.isNonnull(expr, fromType)) {
+        fromType = fromType.nonNullableType;
+      } else if (explicit && fromType.is(TypeFlags.NULLABLE) && !toType.is(TypeFlags.NULLABLE)) {
+        // explicit conversion from nullable to non-nullable requires a runtime
+        // check here because nonnull state above already didn't know better
+        if (!this.options.noAssert) {
+          expr = this.makeRuntimeNonNullCheck(expr, fromType, reportNode);
+        }
+        fromType = fromType.nonNullableType;
+      }
+      if (fromType.isAssignableTo(toType)) { // downcast or same
+        assert(fromType.kind == toType.kind);
+        this.currentType = toType;
+        return expr;
+      }
+      if (explicit && toType.nonNullableType.isAssignableTo(fromType)) { // upcast
+        // <Cat | null>(<Animal>maybeCat)
+        assert(fromType.kind == toType.kind);
+        if (!this.options.noAssert) {
+          expr = this.makeRuntimeUpcastCheck(expr, fromType, toType, reportNode);
+        }
+        this.currentType = toType;
+        return expr;
+      }
+      this.error(
+        DiagnosticCode.Type_0_is_not_assignable_to_type_1,
+        reportNode.range, fromType.toString(), toType.toString()
+      );
+      this.currentType = toType;
+      return module.unreachable();
+    }
+
+    // not dealing with references from here on
 
     if (!fromType.isAssignableTo(toType)) {
       if (!explicit) {
-        if (fromType.nonNullableType == toType) {
-          this.error(
-            DiagnosticCode.Object_is_possibly_null,
-            reportNode.range
-          ); // recoverable
-        } else {
-          this.error(
-            DiagnosticCode.Conversion_from_type_0_to_1_requires_an_explicit_cast,
-            reportNode.range, fromType.toString(), toType.toString()
-          ); // recoverable
-        }
+        this.error(
+          DiagnosticCode.Conversion_from_type_0_to_1_requires_an_explicit_cast,
+          reportNode.range, fromType.toString(), toType.toString()
+        ); // recoverable
       }
     }
 
@@ -3319,19 +3347,9 @@ export class Compiler extends DiagnosticEmitter {
             expression.expression.range
           );
         } else if (!this.options.noAssert) {
-          let module = this.module;
-          let flow = this.currentFlow;
-          let temp = flow.getTempLocal(type);
-          if (!flow.canOverflow(expr, type)) flow.setLocalFlag(temp.index, LocalFlags.WRAPPED);
-          flow.setLocalFlag(temp.index, LocalFlags.NONNULL);
-          expr = module.if(
-            module.local_tee(temp.index, expr),
-            module.local_get(temp.index, type.toNativeType()),
-            module.unreachable()
-          );
-          flow.freeTempLocal(temp);
+          expr = this.makeRuntimeNonNullCheck(expr, type, expression);
         }
-        this.currentType = this.currentType.nonNullableType;
+        this.currentType = type.nonNullableType;
         return expr;
       }
       default: assert(false);
@@ -9376,6 +9394,98 @@ export class Compiler extends DiagnosticEmitter {
     }
     return stmts;
   }
+
+  /** Makes a call to `abort`, if present, otherwise creates a trap. */
+  makeAbort(
+    /** Message argument of type string, if any. */
+    message: Expression | null,
+    /** Code location to report when aborting. */
+    codeLocation: Node
+  ): ExpressionRef {
+    var program = this.program;
+    var module = this.module;
+    var stringInstance = program.stringInstance;
+    var abortInstance = program.abortInstance;
+    if (!abortInstance || !this.compileFunction(abortInstance)) return module.unreachable();
+
+    var messageArg: ExpressionRef;
+    if (message !== null) {
+      // The message argument works much like an arm of an IF that does not become executed if the
+      // assertion succeeds respectively is only being computed if the program actually crashes.
+      // Hence, let's make it so that the autorelease is skipped at the end of the current block,
+      // essentially ignoring the message GC-wise. Doesn't matter anyway on a crash.
+      messageArg = this.compileExpression(message, stringInstance.type, Constraints.CONV_IMPLICIT | Constraints.WILL_RETAIN);
+    } else {
+      messageArg = this.makeZero(stringInstance.type);
+    }
+
+    var filenameArg = this.ensureStaticString(codeLocation.range.source.normalizedPath);
+    return module.block(null, [
+      module.call(
+        abortInstance.internalName, [
+          messageArg,
+          filenameArg,
+          module.i32(codeLocation.range.line),
+          module.i32(codeLocation.range.column)
+        ],
+        NativeType.None
+      ),
+      module.unreachable()
+    ]);
+  }
+
+  /** Makes a runtime non-null check, e.g. on `<Type>possiblyNull` or `possiblyNull!`. */
+  makeRuntimeNonNullCheck(
+    /** Expression being checked. */
+    expr: ExpressionRef,
+    /** Type of the expression. */
+    type: Type,
+    /** Report node. */
+    reportNode: Node
+  ): ExpressionRef {
+    assert(type.is(TypeFlags.NULLABLE | TypeFlags.REFERENCE));
+    var module = this.module;
+    var flow = this.currentFlow;
+    var temp = flow.getTempLocal(type);
+    if (!flow.canOverflow(expr, type)) flow.setLocalFlag(temp.index, LocalFlags.WRAPPED);
+    flow.setLocalFlag(temp.index, LocalFlags.NONNULL);
+    expr = module.if(
+      module.local_tee(temp.index, expr),
+      module.local_get(temp.index, type.toNativeType()),
+      this.makeAbort(null, reportNode) // TODO: throw
+    );
+    flow.freeTempLocal(temp);
+    return expr;
+  }
+
+  /** Makes a runtime upcast check, e.g. on `<Child>parent`. */
+  makeRuntimeUpcastCheck(
+    /** Expression being upcast. */
+    expr: ExpressionRef,
+    /** Type of the expression. */
+    type: Type,
+    /** Type casting to. */
+    toType: Type,
+    /** Report node. */
+    reportNode: Node
+  ): ExpressionRef {
+    assert(toType.is(TypeFlags.REFERENCE) && toType.nonNullableType.isAssignableTo(type));
+    var module = this.module;
+    var flow = this.currentFlow;
+    var temp = flow.getTempLocal(type);
+    var instanceofInstance = this.program.instanceofInstance;
+    assert(this.compileFunction(instanceofInstance));
+    expr = module.if(
+      module.call(instanceofInstance.internalName, [
+        module.local_tee(temp.index, expr),
+        module.i32(assert(toType.classReference).id)
+      ], NativeType.I32),
+      module.local_get(temp.index, type.toNativeType()),
+      this.makeAbort(null, reportNode) // TODO: throw
+    );
+    flow.freeTempLocal(temp);
+    return expr;
+  }
 }
 
 // helpers
diff --git a/std/assembly/rt/tlsf.ts b/std/assembly/rt/tlsf.ts
index e325225018..c6adeb910f 100644
--- a/std/assembly/rt/tlsf.ts
+++ b/std/assembly/rt/tlsf.ts
@@ -498,12 +498,12 @@ export function allocateBlock(root: Root, size: usize): Block {
       block = searchBlock(root, payloadSize);
       if (!block) {
         growMemory(root, payloadSize);
-        block = <Block>searchBlock(root, payloadSize);
+        block = changetype<Block>(searchBlock(root, payloadSize));
         if (DEBUG) assert(block); // must be found now
       }
     } else {
       growMemory(root, payloadSize);
-      block = <Block>searchBlock(root, payloadSize);
+      block = changetype<Block>(searchBlock(root, payloadSize));
       if (DEBUG) assert(block); // must be found now
     }
   }
diff --git a/tests/compiler/assert-nonnull.optimized.wat b/tests/compiler/assert-nonnull.optimized.wat
index 536902c55e..1de0e970bc 100644
--- a/tests/compiler/assert-nonnull.optimized.wat
+++ b/tests/compiler/assert-nonnull.optimized.wat
@@ -4,9 +4,10 @@
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
- (data (i32.const 16) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e")
- (data (i32.const 80) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s")
- (data (i32.const 128) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y")
+ (data (i32.const 16) "\"\00\00\00\01\00\00\00\01\00\00\00\"\00\00\00a\00s\00s\00e\00r\00t\00-\00n\00o\00n\00n\00u\00l\00l\00.\00t\00s")
+ (data (i32.const 80) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e")
+ (data (i32.const 144) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s")
+ (data (i32.const 192) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y")
  (table $0 1 funcref)
  (global $~argumentsLength (mut i32) (i32.const 0))
  (export "__argumentsLength" (global $~argumentsLength))
@@ -17,7 +18,7 @@
  (export "testArr" (func $assert-nonnull/testArr))
  (export "testElem" (func $assert-nonnull/testElem))
  (export "testAll" (func $assert-nonnull/testAll))
- (export "testAll2" (func $assert-nonnull/testAll))
+ (export "testAll2" (func $assert-nonnull/testAll2))
  (export "testFn" (func $assert-nonnull/testFn))
  (export "testFn2" (func $assert-nonnull/testFn2))
  (export "testRet" (func $assert-nonnull/testRet))
@@ -27,6 +28,11 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 2
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
@@ -35,6 +41,11 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 11
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
@@ -46,6 +57,11 @@
   local.tee $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 15
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
@@ -61,8 +77,8 @@
   i32.load offset=12
   i32.ge_u
   if
-   i32.const 32
    i32.const 96
+   i32.const 160
    i32.const 93
    i32.const 41
    call $~lib/builtins/abort
@@ -73,8 +89,8 @@
   local.tee $0
   i32.eqz
   if
-   i32.const 144
-   i32.const 96
+   i32.const 208
+   i32.const 160
    i32.const 97
    i32.const 39
    call $~lib/builtins/abort
@@ -86,6 +102,11 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 19
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
@@ -97,8 +118,8 @@
   i32.load offset=12
   i32.ge_u
   if
-   i32.const 32
    i32.const 96
+   i32.const 160
    i32.const 93
    i32.const 41
    call $~lib/builtins/abort
@@ -113,43 +134,82 @@
   local.tee $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 23
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
  )
  (func $assert-nonnull/testAll (; 9 ;) (param $0 i32) (result i32)
   (local $1 i32)
-  local.get $0
-  i32.eqz
-  if
-   unreachable
-  end
-  local.get $0
-  call $~lib/array/Array<assert-nonnull/Foo | null>#__get
-  local.tee $0
-  local.get $0
-  i32.eqz
-  if
-   unreachable
+  block $folding-inner0
+   local.get $0
+   i32.eqz
+   br_if $folding-inner0
+   local.get $0
+   call $~lib/array/Array<assert-nonnull/Foo | null>#__get
+   local.tee $0
+   local.get $0
+   i32.eqz
+   br_if $folding-inner0
+   i32.load
+   local.tee $0
+   i32.eqz
+   br_if $folding-inner0
+   local.get $0
+   return
   end
-  i32.load
-  local.tee $0
-  i32.eqz
-  if
-   unreachable
+  i32.const 0
+  i32.const 32
+  i32.const 27
+  i32.const 9
+  call $~lib/builtins/abort
+  unreachable
+ )
+ (func $assert-nonnull/testAll2 (; 10 ;) (param $0 i32) (result i32)
+  (local $1 i32)
+  block $folding-inner0
+   local.get $0
+   i32.eqz
+   br_if $folding-inner0
+   local.get $0
+   call $~lib/array/Array<assert-nonnull/Foo | null>#__get
+   local.tee $0
+   local.get $0
+   i32.eqz
+   br_if $folding-inner0
+   i32.load
+   local.tee $0
+   i32.eqz
+   br_if $folding-inner0
+   local.get $0
+   return
   end
-  local.get $0
+  i32.const 0
+  i32.const 32
+  i32.const 31
+  i32.const 9
+  call $~lib/builtins/abort
+  unreachable
  )
- (func $assert-nonnull/testFn (; 10 ;) (param $0 i32) (result i32)
+ (func $assert-nonnull/testFn (; 11 ;) (param $0 i32) (result i32)
   i32.const 0
   global.set $~argumentsLength
   local.get $0
   call_indirect (type $none_=>_i32)
  )
- (func $assert-nonnull/testFn2 (; 11 ;) (param $0 i32) (result i32)
+ (func $assert-nonnull/testFn2 (; 12 ;) (param $0 i32) (result i32)
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 39
+   i32.const 12
+   call $~lib/builtins/abort
    unreachable
   end
   i32.const 0
@@ -157,7 +217,7 @@
   local.get $0
   call_indirect (type $none_=>_i32)
  )
- (func $assert-nonnull/testRet (; 12 ;) (param $0 i32) (result i32)
+ (func $assert-nonnull/testRet (; 13 ;) (param $0 i32) (result i32)
   (local $1 i32)
   i32.const 0
   global.set $~argumentsLength
@@ -167,17 +227,22 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 44
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
  )
- (func $assert-nonnull/testObjFn (; 13 ;) (param $0 i32) (result i32)
+ (func $assert-nonnull/testObjFn (; 14 ;) (param $0 i32) (result i32)
   i32.const 0
   global.set $~argumentsLength
   local.get $0
   i32.load offset=4
   call_indirect (type $none_=>_i32)
  )
- (func $assert-nonnull/testObjRet (; 14 ;) (param $0 i32) (result i32)
+ (func $assert-nonnull/testObjRet (; 15 ;) (param $0 i32) (result i32)
   (local $1 i32)
   i32.const 0
   global.set $~argumentsLength
@@ -188,6 +253,11 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 32
+   i32.const 52
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
  )
diff --git a/tests/compiler/assert-nonnull.untouched.wat b/tests/compiler/assert-nonnull.untouched.wat
index 88bea7f8a1..6c56578575 100644
--- a/tests/compiler/assert-nonnull.untouched.wat
+++ b/tests/compiler/assert-nonnull.untouched.wat
@@ -6,9 +6,10 @@
  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
  (memory $0 1)
- (data (i32.const 16) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e\00")
- (data (i32.const 80) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s\00")
- (data (i32.const 128) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y\00")
+ (data (i32.const 16) "\"\00\00\00\01\00\00\00\01\00\00\00\"\00\00\00a\00s\00s\00e\00r\00t\00-\00n\00o\00n\00n\00u\00l\00l\00.\00t\00s\00")
+ (data (i32.const 80) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e\00")
+ (data (i32.const 144) "\1a\00\00\00\01\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s\00")
+ (data (i32.const 192) "^\00\00\00\01\00\00\00\01\00\00\00^\00\00\00E\00l\00e\00m\00e\00n\00t\00 \00t\00y\00p\00e\00 \00m\00u\00s\00t\00 \00b\00e\00 \00n\00u\00l\00l\00a\00b\00l\00e\00 \00i\00f\00 \00a\00r\00r\00a\00y\00 \00i\00s\00 \00h\00o\00l\00e\00y\00")
  (table $0 1 funcref)
  (global $~argumentsLength (mut i32) (i32.const 0))
  (export "__argumentsLength" (global $~argumentsLength))
@@ -41,6 +42,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 2
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -59,6 +65,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 11
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
@@ -79,6 +90,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 15
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -104,8 +120,8 @@
   i32.load offset=12
   i32.ge_u
   if
-   i32.const 32
    i32.const 96
+   i32.const 160
    i32.const 93
    i32.const 41
    call $~lib/builtins/abort
@@ -120,8 +136,8 @@
   if
    local.get $2
    call $~lib/rt/stub/__release
-   i32.const 144
-   i32.const 96
+   i32.const 208
+   i32.const 160
    i32.const 97
    i32.const 39
    call $~lib/builtins/abort
@@ -139,6 +155,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 19
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.const 0
@@ -165,8 +186,8 @@
   i32.load offset=12
   i32.ge_u
   if
-   i32.const 32
    i32.const 96
+   i32.const 160
    i32.const 93
    i32.const 41
    call $~lib/builtins/abort
@@ -190,6 +211,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 23
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -209,6 +235,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 27
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.const 0
@@ -218,6 +249,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 27
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
@@ -225,6 +261,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 27
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -246,6 +287,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 31
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.const 0
@@ -255,6 +301,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 31
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
@@ -262,6 +313,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 31
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -288,6 +344,11 @@
   if (result i32)
    local.get $1
   else
+   i32.const 0
+   i32.const 32
+   i32.const 39
+   i32.const 12
+   call $~lib/builtins/abort
    unreachable
   end
   local.set $2
@@ -309,6 +370,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 44
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -350,6 +416,11 @@
   if (result i32)
    local.get $2
   else
+   i32.const 0
+   i32.const 32
+   i32.const 52
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
diff --git a/tests/compiler/managed-cast.json b/tests/compiler/managed-cast.json
new file mode 100644
index 0000000000..59c251c705
--- /dev/null
+++ b/tests/compiler/managed-cast.json
@@ -0,0 +1,7 @@
+{
+  "asc_flags": [
+    "--runtime half",
+    "--explicitStart",
+    "--use ASC_RTRACE=1"
+  ]
+}
\ No newline at end of file
diff --git a/tests/compiler/managed-cast.optimized.wat b/tests/compiler/managed-cast.optimized.wat
new file mode 100644
index 0000000000..c0b359a1fc
--- /dev/null
+++ b/tests/compiler/managed-cast.optimized.wat
@@ -0,0 +1,2036 @@
+(module
+ (type $i32_=>_none (func (param i32)))
+ (type $i32_i32_=>_none (func (param i32 i32)))
+ (type $none_=>_none (func))
+ (type $i32_=>_i32 (func (param i32) (result i32)))
+ (type $i32_i32_i32_=>_none (func (param i32 i32 i32)))
+ (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
+ (type $none_=>_i32 (func (result i32)))
+ (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
+ (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
+ (import "rtrace" "onfree" (func $~lib/rt/rtrace/onfree (param i32)))
+ (import "rtrace" "onalloc" (func $~lib/rt/rtrace/onalloc (param i32)))
+ (import "rtrace" "onincrement" (func $~lib/rt/rtrace/onincrement (param i32)))
+ (import "rtrace" "ondecrement" (func $~lib/rt/rtrace/ondecrement (param i32)))
+ (memory $0 1)
+ (data (i32.const 16) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00t\00l\00s\00f\00.\00t\00s")
+ (data (i32.const 64) "(\00\00\00\01\00\00\00\01\00\00\00(\00\00\00a\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e")
+ (data (i32.const 128) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00p\00u\00r\00e\00.\00t\00s")
+ (data (i32.const 176) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e")
+ (data (i32.const 240) "\14\00\00\00\01\00\00\00\01\00\00\00\14\00\00\00~\00l\00i\00b\00/\00r\00t\00.\00t\00s")
+ (data (i32.const 288) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00m\00a\00n\00a\00g\00e\00d\00-\00c\00a\00s\00t\00.\00t\00s")
+ (data (i32.const 336) "\05\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\04\00\00\00\10")
+ (global $~lib/rt/tlsf/ROOT (mut i32) (i32.const 0))
+ (global $~lib/rt/tlsf/collectLock (mut i32) (i32.const 0))
+ (global $~lib/rt/pure/ROOTS (mut i32) (i32.const 0))
+ (global $~lib/rt/pure/CUR (mut i32) (i32.const 0))
+ (global $~lib/rt/pure/END (mut i32) (i32.const 0))
+ (global $~started (mut i32) (i32.const 0))
+ (export "_start" (func $~start))
+ (export "memory" (memory $0))
+ (func $~lib/rt/tlsf/removeBlock (; 5 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  local.get $1
+  i32.load
+  local.tee $3
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 277
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const -4
+  i32.and
+  local.tee $2
+  i32.const 16
+  i32.ge_u
+  if (result i32)
+   local.get $2
+   i32.const 1073741808
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 279
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $2
+  i32.const 256
+  i32.lt_u
+  if (result i32)
+   local.get $2
+   i32.const 4
+   i32.shr_u
+   local.set $2
+   i32.const 0
+  else
+   local.get $2
+   i32.const 31
+   local.get $2
+   i32.clz
+   i32.sub
+   local.tee $3
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 16
+   i32.xor
+   local.set $2
+   local.get $3
+   i32.const 7
+   i32.sub
+  end
+  local.tee $3
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $2
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 292
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load offset=20
+  local.set $4
+  local.get $1
+  i32.load offset=16
+  local.tee $5
+  if
+   local.get $5
+   local.get $4
+   i32.store offset=20
+  end
+  local.get $4
+  if
+   local.get $4
+   local.get $5
+   i32.store offset=16
+  end
+  local.get $1
+  local.get $0
+  local.get $2
+  local.get $3
+  i32.const 4
+  i32.shl
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=96
+  i32.eq
+  if
+   local.get $0
+   local.get $2
+   local.get $3
+   i32.const 4
+   i32.shl
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   local.get $4
+   i32.store offset=96
+   local.get $4
+   i32.eqz
+   if
+    local.get $0
+    local.get $3
+    i32.const 2
+    i32.shl
+    i32.add
+    local.get $0
+    local.get $3
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=4
+    i32.const 1
+    local.get $2
+    i32.shl
+    i32.const -1
+    i32.xor
+    i32.and
+    local.tee $1
+    i32.store offset=4
+    local.get $1
+    i32.eqz
+    if
+     local.get $0
+     local.get $0
+     i32.load
+     i32.const 1
+     local.get $3
+     i32.shl
+     i32.const -1
+     i32.xor
+     i32.and
+     i32.store
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/insertBlock (; 6 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  local.get $1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 205
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load
+  local.tee $3
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 207
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 16
+  i32.add
+  local.get $1
+  i32.load
+  i32.const -4
+  i32.and
+  i32.add
+  local.tee $4
+  i32.load
+  local.tee $5
+  i32.const 1
+  i32.and
+  if
+   local.get $3
+   i32.const -4
+   i32.and
+   i32.const 16
+   i32.add
+   local.get $5
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $2
+   i32.const 1073741808
+   i32.lt_u
+   if
+    local.get $0
+    local.get $4
+    call $~lib/rt/tlsf/removeBlock
+    local.get $1
+    local.get $2
+    local.get $3
+    i32.const 3
+    i32.and
+    i32.or
+    local.tee $3
+    i32.store
+    local.get $1
+    i32.const 16
+    i32.add
+    local.get $1
+    i32.load
+    i32.const -4
+    i32.and
+    i32.add
+    local.tee $4
+    i32.load
+    local.set $5
+   end
+  end
+  local.get $3
+  i32.const 2
+  i32.and
+  if
+   local.get $1
+   i32.const 4
+   i32.sub
+   i32.load
+   local.tee $2
+   i32.load
+   local.tee $6
+   i32.const 1
+   i32.and
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 228
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $6
+   i32.const -4
+   i32.and
+   i32.const 16
+   i32.add
+   local.get $3
+   i32.const -4
+   i32.and
+   i32.add
+   local.tee $7
+   i32.const 1073741808
+   i32.lt_u
+   if
+    local.get $0
+    local.get $2
+    call $~lib/rt/tlsf/removeBlock
+    local.get $2
+    local.get $7
+    local.get $6
+    i32.const 3
+    i32.and
+    i32.or
+    local.tee $3
+    i32.store
+    local.get $2
+    local.set $1
+   end
+  end
+  local.get $4
+  local.get $5
+  i32.const 2
+  i32.or
+  i32.store
+  local.get $3
+  i32.const -4
+  i32.and
+  local.tee $2
+  i32.const 16
+  i32.ge_u
+  if (result i32)
+   local.get $2
+   i32.const 1073741808
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 243
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $2
+  local.get $1
+  i32.const 16
+  i32.add
+  i32.add
+  local.get $4
+  i32.ne
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 244
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $4
+  i32.const 4
+  i32.sub
+  local.get $1
+  i32.store
+  local.get $2
+  i32.const 256
+  i32.lt_u
+  if (result i32)
+   local.get $2
+   i32.const 4
+   i32.shr_u
+   local.set $4
+   i32.const 0
+  else
+   local.get $2
+   i32.const 31
+   local.get $2
+   i32.clz
+   i32.sub
+   local.tee $2
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 16
+   i32.xor
+   local.set $4
+   local.get $2
+   i32.const 7
+   i32.sub
+  end
+  local.tee $3
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $4
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 260
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $4
+  local.get $3
+  i32.const 4
+  i32.shl
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=96
+  local.set $2
+  local.get $1
+  i32.const 0
+  i32.store offset=16
+  local.get $1
+  local.get $2
+  i32.store offset=20
+  local.get $2
+  if
+   local.get $2
+   local.get $1
+   i32.store offset=16
+  end
+  local.get $0
+  local.get $4
+  local.get $3
+  i32.const 4
+  i32.shl
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $1
+  i32.store offset=96
+  local.get $0
+  local.get $0
+  i32.load
+  i32.const 1
+  local.get $3
+  i32.shl
+  i32.or
+  i32.store
+  local.get $0
+  local.get $3
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $0
+  local.get $3
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=4
+  i32.const 1
+  local.get $4
+  i32.shl
+  i32.or
+  i32.store offset=4
+ )
+ (func $~lib/rt/tlsf/addMemory (; 7 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  local.get $2
+  i32.const 15
+  i32.and
+  i32.eqz
+  i32.const 0
+  local.get $1
+  i32.const 15
+  i32.and
+  i32.eqz
+  i32.const 0
+  local.get $1
+  local.get $2
+  i32.le_u
+  select
+  select
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 386
+   i32.const 4
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  i32.load offset=1568
+  local.tee $3
+  if
+   local.get $1
+   local.get $3
+   i32.const 16
+   i32.add
+   i32.lt_u
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 396
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $3
+   local.get $1
+   i32.const 16
+   i32.sub
+   i32.eq
+   if
+    local.get $3
+    i32.load
+    local.set $4
+    local.get $1
+    i32.const 16
+    i32.sub
+    local.set $1
+   end
+  else
+   local.get $1
+   local.get $0
+   i32.const 1572
+   i32.add
+   i32.lt_u
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 408
+    i32.const 4
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  local.get $2
+  local.get $1
+  i32.sub
+  local.tee $2
+  i32.const 48
+  i32.lt_u
+  if
+   return
+  end
+  local.get $1
+  local.get $4
+  i32.const 2
+  i32.and
+  local.get $2
+  i32.const 32
+  i32.sub
+  i32.const 1
+  i32.or
+  i32.or
+  i32.store
+  local.get $1
+  i32.const 0
+  i32.store offset=16
+  local.get $1
+  i32.const 0
+  i32.store offset=20
+  local.get $1
+  local.get $2
+  i32.add
+  i32.const 16
+  i32.sub
+  local.tee $2
+  i32.const 2
+  i32.store
+  local.get $0
+  local.get $2
+  i32.store offset=1568
+  local.get $0
+  local.get $1
+  call $~lib/rt/tlsf/insertBlock
+ )
+ (func $~lib/rt/tlsf/maybeInitialize (; 8 ;) (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  global.get $~lib/rt/tlsf/ROOT
+  local.tee $0
+  i32.eqz
+  if
+   i32.const 1
+   memory.size
+   local.tee $0
+   i32.gt_s
+   if (result i32)
+    i32.const 1
+    local.get $0
+    i32.sub
+    memory.grow
+    i32.const 0
+    i32.lt_s
+   else
+    i32.const 0
+   end
+   if
+    unreachable
+   end
+   i32.const 384
+   local.tee $0
+   i32.const 0
+   i32.store
+   i32.const 1952
+   i32.const 0
+   i32.store
+   loop $for-loop|0
+    local.get $1
+    i32.const 23
+    i32.lt_u
+    if
+     local.get $1
+     i32.const 2
+     i32.shl
+     i32.const 384
+     i32.add
+     i32.const 0
+     i32.store offset=4
+     i32.const 0
+     local.set $2
+     loop $for-loop|1
+      local.get $2
+      i32.const 16
+      i32.lt_u
+      if
+       local.get $1
+       i32.const 4
+       i32.shl
+       local.get $2
+       i32.add
+       i32.const 2
+       i32.shl
+       i32.const 384
+       i32.add
+       i32.const 0
+       i32.store offset=96
+       local.get $2
+       i32.const 1
+       i32.add
+       local.set $2
+       br $for-loop|1
+      end
+     end
+     local.get $1
+     i32.const 1
+     i32.add
+     local.set $1
+     br $for-loop|0
+    end
+   end
+   i32.const 384
+   i32.const 1968
+   memory.size
+   i32.const 16
+   i32.shl
+   call $~lib/rt/tlsf/addMemory
+   i32.const 384
+   global.set $~lib/rt/tlsf/ROOT
+  end
+  local.get $0
+ )
+ (func $~lib/rt/tlsf/prepareSize (; 9 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.const 1073741808
+  i32.ge_u
+  if
+   i32.const 80
+   i32.const 32
+   i32.const 457
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  i32.const 15
+  i32.add
+  i32.const -16
+  i32.and
+  local.tee $0
+  i32.const 16
+  local.get $0
+  i32.const 16
+  i32.gt_u
+  select
+ )
+ (func $~lib/rt/tlsf/searchBlock (; 10 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  local.get $1
+  i32.const 256
+  i32.lt_u
+  if (result i32)
+   local.get $1
+   i32.const 4
+   i32.shr_u
+   local.set $1
+   i32.const 0
+  else
+   local.get $1
+   i32.const 536870904
+   i32.lt_u
+   if
+    local.get $1
+    i32.const 1
+    i32.const 27
+    local.get $1
+    i32.clz
+    i32.sub
+    i32.shl
+    i32.add
+    i32.const 1
+    i32.sub
+    local.set $1
+   end
+   local.get $1
+   i32.const 31
+   local.get $1
+   i32.clz
+   i32.sub
+   local.tee $2
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 16
+   i32.xor
+   local.set $1
+   local.get $2
+   i32.const 7
+   i32.sub
+  end
+  local.tee $2
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $1
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 338
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $2
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=4
+  i32.const -1
+  local.get $1
+  i32.shl
+  i32.and
+  local.tee $1
+  if (result i32)
+   local.get $0
+   local.get $1
+   i32.ctz
+   local.get $2
+   i32.const 4
+   i32.shl
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=96
+  else
+   local.get $0
+   i32.load
+   i32.const -1
+   local.get $2
+   i32.const 1
+   i32.add
+   i32.shl
+   i32.and
+   local.tee $1
+   if (result i32)
+    local.get $0
+    local.get $1
+    i32.ctz
+    local.tee $1
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=4
+    local.tee $2
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 32
+     i32.const 351
+     i32.const 17
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    local.get $2
+    i32.ctz
+    local.get $1
+    i32.const 4
+    i32.shl
+    i32.add
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=96
+   else
+    i32.const 0
+   end
+  end
+ )
+ (func $~lib/rt/pure/markGray (; 11 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.tee $1
+  i32.const 1879048192
+  i32.and
+  i32.const 268435456
+  i32.ne
+  if
+   local.get $0
+   local.get $1
+   i32.const -1879048193
+   i32.and
+   i32.const 268435456
+   i32.or
+   i32.store offset=4
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 2
+   call $~lib/rt/__visit_members
+  end
+ )
+ (func $~lib/rt/tlsf/freeBlock (; 12 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  local.get $1
+  i32.load
+  local.tee $2
+  i32.const 1
+  i32.and
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 569
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  local.get $2
+  i32.const 1
+  i32.or
+  i32.store
+  local.get $0
+  local.get $1
+  call $~lib/rt/tlsf/insertBlock
+  local.get $1
+  call $~lib/rt/rtrace/onfree
+ )
+ (func $~lib/rt/pure/scanBlack (; 13 ;) (param $0 i32)
+  local.get $0
+  local.get $0
+  i32.load offset=4
+  i32.const -1879048193
+  i32.and
+  i32.store offset=4
+  local.get $0
+  i32.const 16
+  i32.add
+  i32.const 4
+  call $~lib/rt/__visit_members
+ )
+ (func $~lib/rt/pure/scan (; 14 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.tee $1
+  i32.const 1879048192
+  i32.and
+  i32.const 268435456
+  i32.eq
+  if
+   local.get $1
+   i32.const 268435455
+   i32.and
+   i32.const 0
+   i32.gt_u
+   if
+    local.get $0
+    call $~lib/rt/pure/scanBlack
+   else
+    local.get $0
+    local.get $1
+    i32.const -1879048193
+    i32.and
+    i32.const 536870912
+    i32.or
+    i32.store offset=4
+    local.get $0
+    i32.const 16
+    i32.add
+    i32.const 3
+    call $~lib/rt/__visit_members
+   end
+  end
+ )
+ (func $~lib/rt/pure/collectWhite (; 15 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.tee $1
+  i32.const 1879048192
+  i32.and
+  i32.const 536870912
+  i32.eq
+  if (result i32)
+   local.get $1
+   i32.const -2147483648
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  if
+   local.get $0
+   local.get $1
+   i32.const -1879048193
+   i32.and
+   i32.store offset=4
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 5
+   call $~lib/rt/__visit_members
+   global.get $~lib/rt/tlsf/ROOT
+   local.get $0
+   call $~lib/rt/tlsf/freeBlock
+  end
+ )
+ (func $~lib/rt/pure/__collect (; 16 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  global.get $~lib/rt/pure/ROOTS
+  local.tee $5
+  local.tee $2
+  local.set $3
+  global.get $~lib/rt/pure/CUR
+  local.set $0
+  loop $for-loop|0
+   local.get $3
+   local.get $0
+   i32.lt_u
+   if
+    local.get $3
+    i32.load
+    local.tee $4
+    i32.load offset=4
+    local.tee $1
+    i32.const 1879048192
+    i32.and
+    i32.const 805306368
+    i32.eq
+    if (result i32)
+     local.get $1
+     i32.const 268435455
+     i32.and
+     i32.const 0
+     i32.gt_u
+    else
+     i32.const 0
+    end
+    if
+     local.get $4
+     call $~lib/rt/pure/markGray
+     local.get $2
+     local.get $4
+     i32.store
+     local.get $2
+     i32.const 4
+     i32.add
+     local.set $2
+    else
+     i32.const 0
+     local.get $1
+     i32.const 268435455
+     i32.and
+     i32.eqz
+     local.get $1
+     i32.const 1879048192
+     i32.and
+     select
+     if
+      global.get $~lib/rt/tlsf/ROOT
+      local.get $4
+      call $~lib/rt/tlsf/freeBlock
+     else
+      local.get $4
+      local.get $1
+      i32.const 2147483647
+      i32.and
+      i32.store offset=4
+     end
+    end
+    local.get $3
+    i32.const 4
+    i32.add
+    local.set $3
+    br $for-loop|0
+   end
+  end
+  local.get $2
+  global.set $~lib/rt/pure/CUR
+  local.get $5
+  local.set $0
+  loop $for-loop|1
+   local.get $0
+   local.get $2
+   i32.lt_u
+   if
+    local.get $0
+    i32.load
+    call $~lib/rt/pure/scan
+    local.get $0
+    i32.const 4
+    i32.add
+    local.set $0
+    br $for-loop|1
+   end
+  end
+  local.get $5
+  local.set $0
+  loop $for-loop|2
+   local.get $0
+   local.get $2
+   i32.lt_u
+   if
+    local.get $0
+    i32.load
+    local.tee $1
+    local.get $1
+    i32.load offset=4
+    i32.const 2147483647
+    i32.and
+    i32.store offset=4
+    local.get $1
+    call $~lib/rt/pure/collectWhite
+    local.get $0
+    i32.const 4
+    i32.add
+    local.set $0
+    br $for-loop|2
+   end
+  end
+  local.get $5
+  global.set $~lib/rt/pure/CUR
+ )
+ (func $~lib/rt/tlsf/growMemory (; 17 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  memory.size
+  local.tee $2
+  i32.const 16
+  local.get $0
+  i32.load offset=1568
+  local.get $2
+  i32.const 16
+  i32.shl
+  i32.const 16
+  i32.sub
+  i32.ne
+  i32.shl
+  local.get $1
+  i32.const 1
+  i32.const 27
+  local.get $1
+  i32.clz
+  i32.sub
+  i32.shl
+  i32.const 1
+  i32.sub
+  i32.add
+  local.get $1
+  local.get $1
+  i32.const 536870904
+  i32.lt_u
+  select
+  i32.add
+  i32.const 65535
+  i32.add
+  i32.const -65536
+  i32.and
+  i32.const 16
+  i32.shr_u
+  local.tee $1
+  local.get $2
+  local.get $1
+  i32.gt_s
+  select
+  memory.grow
+  i32.const 0
+  i32.lt_s
+  if
+   local.get $1
+   memory.grow
+   i32.const 0
+   i32.lt_s
+   if
+    unreachable
+   end
+  end
+  local.get $0
+  local.get $2
+  i32.const 16
+  i32.shl
+  memory.size
+  i32.const 16
+  i32.shl
+  call $~lib/rt/tlsf/addMemory
+ )
+ (func $~lib/rt/tlsf/prepareBlock (; 18 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  local.get $1
+  i32.load
+  local.set $3
+  local.get $2
+  i32.const 15
+  i32.and
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 365
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const -4
+  i32.and
+  local.get $2
+  i32.sub
+  local.tee $4
+  i32.const 32
+  i32.ge_u
+  if
+   local.get $1
+   local.get $2
+   local.get $3
+   i32.const 2
+   i32.and
+   i32.or
+   i32.store
+   local.get $2
+   local.get $1
+   i32.const 16
+   i32.add
+   i32.add
+   local.tee $1
+   local.get $4
+   i32.const 16
+   i32.sub
+   i32.const 1
+   i32.or
+   i32.store
+   local.get $0
+   local.get $1
+   call $~lib/rt/tlsf/insertBlock
+  else
+   local.get $1
+   local.get $3
+   i32.const -2
+   i32.and
+   i32.store
+   local.get $1
+   i32.const 16
+   i32.add
+   local.get $1
+   i32.load
+   i32.const -4
+   i32.and
+   i32.add
+   local.get $1
+   i32.const 16
+   i32.add
+   local.get $1
+   i32.load
+   i32.const -4
+   i32.and
+   i32.add
+   i32.load
+   i32.const -3
+   i32.and
+   i32.store
+  end
+ )
+ (func $~lib/rt/tlsf/allocateBlock (; 19 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  (local $3 i32)
+  global.get $~lib/rt/tlsf/collectLock
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 490
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $1
+  call $~lib/rt/tlsf/prepareSize
+  local.tee $3
+  call $~lib/rt/tlsf/searchBlock
+  local.tee $2
+  i32.eqz
+  if
+   i32.const 1
+   global.set $~lib/rt/tlsf/collectLock
+   call $~lib/rt/pure/__collect
+   i32.const 0
+   global.set $~lib/rt/tlsf/collectLock
+   local.get $0
+   local.get $3
+   call $~lib/rt/tlsf/searchBlock
+   local.tee $2
+   i32.eqz
+   if
+    local.get $0
+    local.get $3
+    call $~lib/rt/tlsf/growMemory
+    local.get $0
+    local.get $3
+    call $~lib/rt/tlsf/searchBlock
+    local.tee $2
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 32
+     i32.const 502
+     i32.const 19
+     call $~lib/builtins/abort
+     unreachable
+    end
+   end
+  end
+  local.get $2
+  i32.load
+  i32.const -4
+  i32.and
+  local.get $3
+  i32.lt_u
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 510
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $2
+  i32.const 0
+  i32.store offset=4
+  local.get $2
+  local.get $1
+  i32.store offset=12
+  local.get $0
+  local.get $2
+  call $~lib/rt/tlsf/removeBlock
+  local.get $0
+  local.get $2
+  local.get $3
+  call $~lib/rt/tlsf/prepareBlock
+  local.get $2
+  call $~lib/rt/rtrace/onalloc
+  local.get $2
+ )
+ (func $~lib/rt/tlsf/__alloc (; 20 ;) (param $0 i32) (param $1 i32) (result i32)
+  call $~lib/rt/tlsf/maybeInitialize
+  local.get $0
+  call $~lib/rt/tlsf/allocateBlock
+  local.tee $0
+  local.get $1
+  i32.store offset=8
+  local.get $0
+  i32.const 16
+  i32.add
+ )
+ (func $~lib/rt/pure/increment (; 21 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.tee $1
+  i32.const -268435456
+  i32.and
+  local.get $1
+  i32.const 1
+  i32.add
+  i32.const -268435456
+  i32.and
+  i32.ne
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 104
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $1
+  i32.const 1
+  i32.add
+  i32.store offset=4
+  local.get $0
+  call $~lib/rt/rtrace/onincrement
+  local.get $0
+  i32.load
+  i32.const 1
+  i32.and
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 107
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $~lib/rt/pure/__retain (; 22 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.const 380
+  i32.gt_u
+  if
+   local.get $0
+   i32.const 16
+   i32.sub
+   call $~lib/rt/pure/increment
+  end
+  local.get $0
+ )
+ (func $managed-cast/Cat#constructor (; 23 ;) (result i32)
+  (local $0 i32)
+  i32.const 0
+  i32.const 3
+  call $~lib/rt/tlsf/__alloc
+  call $~lib/rt/pure/__retain
+  local.tee $0
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 4
+   call $~lib/rt/tlsf/__alloc
+   call $~lib/rt/pure/__retain
+   local.set $0
+  end
+  local.get $0
+ )
+ (func $~lib/rt/__typeinfo (; 24 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.const 336
+  i32.load
+  i32.gt_u
+  if
+   i32.const 192
+   i32.const 256
+   i32.const 22
+   i32.const 27
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  i32.const 3
+  i32.shl
+  i32.const 340
+  i32.add
+  i32.load
+ )
+ (func $~lib/memory/memory.copy (; 25 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  block $~lib/util/memory/memmove|inlined.0
+   local.get $2
+   local.set $3
+   local.get $0
+   local.get $1
+   i32.eq
+   br_if $~lib/util/memory/memmove|inlined.0
+   local.get $0
+   local.get $1
+   i32.lt_u
+   if
+    local.get $1
+    i32.const 7
+    i32.and
+    local.get $0
+    i32.const 7
+    i32.and
+    i32.eq
+    if
+     loop $while-continue|0
+      local.get $0
+      i32.const 7
+      i32.and
+      if
+       local.get $3
+       i32.eqz
+       br_if $~lib/util/memory/memmove|inlined.0
+       local.get $3
+       i32.const 1
+       i32.sub
+       local.set $3
+       local.get $0
+       local.tee $2
+       i32.const 1
+       i32.add
+       local.set $0
+       local.get $1
+       local.tee $4
+       i32.const 1
+       i32.add
+       local.set $1
+       local.get $2
+       local.get $4
+       i32.load8_u
+       i32.store8
+       br $while-continue|0
+      end
+     end
+     loop $while-continue|1
+      local.get $3
+      i32.const 8
+      i32.ge_u
+      if
+       local.get $0
+       local.get $1
+       i64.load
+       i64.store
+       local.get $3
+       i32.const 8
+       i32.sub
+       local.set $3
+       local.get $0
+       i32.const 8
+       i32.add
+       local.set $0
+       local.get $1
+       i32.const 8
+       i32.add
+       local.set $1
+       br $while-continue|1
+      end
+     end
+    end
+    loop $while-continue|2
+     local.get $3
+     if
+      local.get $0
+      local.tee $2
+      i32.const 1
+      i32.add
+      local.set $0
+      local.get $1
+      local.tee $4
+      i32.const 1
+      i32.add
+      local.set $1
+      local.get $2
+      local.get $4
+      i32.load8_u
+      i32.store8
+      local.get $3
+      i32.const 1
+      i32.sub
+      local.set $3
+      br $while-continue|2
+     end
+    end
+   else
+    local.get $1
+    i32.const 7
+    i32.and
+    local.get $0
+    i32.const 7
+    i32.and
+    i32.eq
+    if
+     loop $while-continue|3
+      local.get $0
+      local.get $3
+      i32.add
+      i32.const 7
+      i32.and
+      if
+       local.get $3
+       i32.eqz
+       br_if $~lib/util/memory/memmove|inlined.0
+       local.get $3
+       i32.const 1
+       i32.sub
+       local.tee $3
+       local.get $0
+       i32.add
+       local.get $1
+       local.get $3
+       i32.add
+       i32.load8_u
+       i32.store8
+       br $while-continue|3
+      end
+     end
+     loop $while-continue|4
+      local.get $3
+      i32.const 8
+      i32.ge_u
+      if
+       local.get $3
+       i32.const 8
+       i32.sub
+       local.tee $3
+       local.get $0
+       i32.add
+       local.get $1
+       local.get $3
+       i32.add
+       i64.load
+       i64.store
+       br $while-continue|4
+      end
+     end
+    end
+    loop $while-continue|5
+     local.get $3
+     if
+      local.get $3
+      i32.const 1
+      i32.sub
+      local.tee $3
+      local.get $0
+      i32.add
+      local.get $1
+      local.get $3
+      i32.add
+      i32.load8_u
+      i32.store8
+      br $while-continue|5
+     end
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/__free (; 26 ;) (param $0 i32)
+  local.get $0
+  i32.const 15
+  i32.and
+  i32.eqz
+  i32.const 0
+  local.get $0
+  select
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 593
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $~lib/rt/tlsf/maybeInitialize
+  local.get $0
+  i32.const 16
+  i32.sub
+  call $~lib/rt/tlsf/freeBlock
+ )
+ (func $~lib/rt/pure/growRoots (; 27 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  global.get $~lib/rt/pure/CUR
+  global.get $~lib/rt/pure/ROOTS
+  local.tee $1
+  i32.sub
+  local.tee $2
+  i32.const 1
+  i32.shl
+  local.tee $0
+  i32.const 256
+  local.get $0
+  i32.const 256
+  i32.gt_u
+  select
+  local.tee $3
+  i32.const 0
+  call $~lib/rt/tlsf/__alloc
+  local.tee $0
+  i32.const 16
+  i32.sub
+  call $~lib/rt/rtrace/onfree
+  local.get $0
+  local.get $1
+  local.get $2
+  call $~lib/memory/memory.copy
+  local.get $1
+  if
+   local.get $1
+   i32.const 16
+   i32.sub
+   call $~lib/rt/rtrace/onalloc
+   local.get $1
+   call $~lib/rt/tlsf/__free
+  end
+  local.get $0
+  global.set $~lib/rt/pure/ROOTS
+  local.get $0
+  local.get $2
+  i32.add
+  global.set $~lib/rt/pure/CUR
+  local.get $0
+  local.get $3
+  i32.add
+  global.set $~lib/rt/pure/END
+ )
+ (func $~lib/rt/pure/appendRoot (; 28 ;) (param $0 i32)
+  (local $1 i32)
+  global.get $~lib/rt/pure/CUR
+  local.tee $1
+  global.get $~lib/rt/pure/END
+  i32.ge_u
+  if
+   call $~lib/rt/pure/growRoots
+   global.get $~lib/rt/pure/CUR
+   local.set $1
+  end
+  local.get $1
+  local.get $0
+  i32.store
+  local.get $1
+  i32.const 4
+  i32.add
+  global.set $~lib/rt/pure/CUR
+ )
+ (func $~lib/rt/pure/decrement (; 29 ;) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  i32.load offset=4
+  local.tee $2
+  i32.const 268435455
+  i32.and
+  local.set $1
+  local.get $0
+  call $~lib/rt/rtrace/ondecrement
+  local.get $0
+  i32.load
+  i32.const 1
+  i32.and
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 115
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 1
+  i32.eq
+  if
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 1
+   call $~lib/rt/__visit_members
+   local.get $2
+   i32.const -2147483648
+   i32.and
+   if
+    local.get $0
+    i32.const -2147483648
+    i32.store offset=4
+   else
+    global.get $~lib/rt/tlsf/ROOT
+    local.get $0
+    call $~lib/rt/tlsf/freeBlock
+   end
+  else
+   local.get $1
+   i32.const 0
+   i32.le_u
+   if
+    i32.const 0
+    i32.const 144
+    i32.const 124
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $0
+   i32.load offset=8
+   call $~lib/rt/__typeinfo
+   i32.const 16
+   i32.and
+   if
+    local.get $0
+    local.get $1
+    i32.const 1
+    i32.sub
+    local.get $2
+    i32.const -268435456
+    i32.and
+    i32.or
+    i32.store offset=4
+   else
+    local.get $0
+    local.get $1
+    i32.const 1
+    i32.sub
+    i32.const -1342177280
+    i32.or
+    i32.store offset=4
+    local.get $2
+    i32.const -2147483648
+    i32.and
+    i32.eqz
+    if
+     local.get $0
+     call $~lib/rt/pure/appendRoot
+    end
+   end
+  end
+ )
+ (func $~lib/rt/pure/__release (; 30 ;) (param $0 i32)
+  local.get $0
+  i32.const 380
+  i32.gt_u
+  if
+   local.get $0
+   i32.const 16
+   i32.sub
+   call $~lib/rt/pure/decrement
+  end
+ )
+ (func $~lib/rt/__instanceof (; 31 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.const 16
+  i32.sub
+  i32.load offset=8
+  local.tee $0
+  i32.const 336
+  i32.load
+  i32.le_u
+  if
+   loop $do-continue|0
+    local.get $0
+    i32.const 3
+    i32.eq
+    if
+     i32.const 1
+     return
+    end
+    local.get $0
+    i32.const 3
+    i32.shl
+    i32.const 340
+    i32.add
+    i32.load offset=4
+    local.tee $0
+    br_if $do-continue|0
+   end
+  end
+  i32.const 0
+ )
+ (func $managed-cast/testUpcastFromNullable (; 32 ;) (param $0 i32)
+  block $folding-inner0
+   local.get $0
+   i32.eqz
+   br_if $folding-inner0
+   local.get $0
+   call $~lib/rt/__instanceof
+   i32.eqz
+   br_if $folding-inner0
+   return
+  end
+  i32.const 0
+  i32.const 304
+  i32.const 36
+  i32.const 8
+  call $~lib/builtins/abort
+  unreachable
+ )
+ (func $start:managed-cast (; 33 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  call $managed-cast/Cat#constructor
+  call $managed-cast/Cat#constructor
+  local.tee $1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 304
+   i32.const 14
+   i32.const 11
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Cat#constructor
+  local.set $2
+  call $managed-cast/Cat#constructor
+  local.set $3
+  call $managed-cast/Cat#constructor
+  local.tee $4
+  call $~lib/rt/__instanceof
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 304
+   i32.const 31
+   i32.const 8
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Cat#constructor
+  local.tee $5
+  call $managed-cast/testUpcastFromNullable
+  call $managed-cast/Cat#constructor
+  local.tee $6
+  call $~lib/rt/__instanceof
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 304
+   i32.const 41
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Cat#constructor
+  local.tee $7
+  call $~lib/rt/__instanceof
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 304
+   i32.const 47
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $~lib/rt/pure/__release
+  local.get $1
+  call $~lib/rt/pure/__release
+  local.get $2
+  call $~lib/rt/pure/__release
+  local.get $3
+  call $~lib/rt/pure/__release
+  local.get $4
+  call $~lib/rt/pure/__release
+  local.get $5
+  call $~lib/rt/pure/__release
+  local.get $6
+  call $~lib/rt/pure/__release
+  local.get $7
+  call $~lib/rt/pure/__release
+ )
+ (func $~start (; 34 ;)
+  global.get $~started
+  if
+   return
+  else
+   i32.const 1
+   global.set $~started
+  end
+  call $start:managed-cast
+ )
+ (func $~lib/rt/pure/__visit (; 35 ;) (param $0 i32) (param $1 i32)
+  local.get $0
+  i32.const 380
+  i32.lt_u
+  if
+   return
+  end
+  local.get $0
+  i32.const 16
+  i32.sub
+  local.set $0
+  block $break|0
+   block $case5|0
+    block $case4|0
+     block $case3|0
+      block $case2|0
+       block $case1|0
+        local.get $1
+        i32.const 1
+        i32.ne
+        if
+         local.get $1
+         i32.const 2
+         i32.sub
+         br_table $case1|0 $case2|0 $case3|0 $case4|0 $case5|0
+        end
+        local.get $0
+        call $~lib/rt/pure/decrement
+        br $break|0
+       end
+       local.get $0
+       i32.load offset=4
+       i32.const 268435455
+       i32.and
+       i32.const 0
+       i32.le_u
+       if
+        i32.const 0
+        i32.const 144
+        i32.const 75
+        i32.const 17
+        call $~lib/builtins/abort
+        unreachable
+       end
+       local.get $0
+       local.get $0
+       i32.load offset=4
+       i32.const 1
+       i32.sub
+       i32.store offset=4
+       local.get $0
+       call $~lib/rt/pure/markGray
+       br $break|0
+      end
+      local.get $0
+      call $~lib/rt/pure/scan
+      br $break|0
+     end
+     local.get $0
+     i32.load offset=4
+     local.tee $1
+     i32.const -268435456
+     i32.and
+     local.get $1
+     i32.const 1
+     i32.add
+     i32.const -268435456
+     i32.and
+     i32.ne
+     if
+      i32.const 0
+      i32.const 144
+      i32.const 86
+      i32.const 6
+      call $~lib/builtins/abort
+      unreachable
+     end
+     local.get $0
+     local.get $1
+     i32.const 1
+     i32.add
+     i32.store offset=4
+     local.get $1
+     i32.const 1879048192
+     i32.and
+     if
+      local.get $0
+      call $~lib/rt/pure/scanBlack
+     end
+     br $break|0
+    end
+    local.get $0
+    call $~lib/rt/pure/collectWhite
+    br $break|0
+   end
+   i32.const 0
+   i32.const 144
+   i32.const 97
+   i32.const 24
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $~lib/rt/__visit_members (; 36 ;) (param $0 i32) (param $1 i32)
+  block $switch$1$default
+   block $switch$1$case$4
+    block $switch$1$case$2
+     local.get $0
+     i32.const 8
+     i32.sub
+     i32.load
+     br_table $switch$1$case$2 $switch$1$case$2 $switch$1$case$4 $switch$1$case$2 $switch$1$case$2 $switch$1$default
+    end
+    return
+   end
+   local.get $0
+   i32.load
+   local.tee $0
+   if
+    local.get $0
+    local.get $1
+    call $~lib/rt/pure/__visit
+   end
+   return
+  end
+  unreachable
+ )
+)
diff --git a/tests/compiler/managed-cast.ts b/tests/compiler/managed-cast.ts
new file mode 100644
index 0000000000..d3ea53b229
--- /dev/null
+++ b/tests/compiler/managed-cast.ts
@@ -0,0 +1,50 @@
+class Animal {
+  tame(): void {}
+}
+class Cat extends Animal {
+  meow(): void {}
+}
+
+function testDowncast(cat: Cat): void {
+  (<Animal>cat).tame();
+}
+testDowncast(new Cat());
+
+function testDowncastFromNullable(cat: Cat | null): void {
+  (<Animal>cat).tame();
+}
+testDowncastFromNullable(new Cat());
+
+function testDowncastToNullable(cat: Cat): void {
+  var maybeAnimal = <Animal | null>cat;
+  if (maybeAnimal) maybeAnimal.tame();
+}
+testDowncastToNullable(new Cat());
+
+function testDowncastFromToNullable(cat: Cat | null): void {
+  var maybeAnimal = <Animal | null>cat;
+  if (maybeAnimal) maybeAnimal.tame();
+}
+testDowncastFromToNullable(new Cat());
+
+function testUpcast(animal: Animal): void {
+  (<Cat>animal).meow();
+}
+testUpcast(new Cat());
+
+function testUpcastFromNullable(animal: Animal | null): void {
+  (<Cat>animal).meow();
+}
+testUpcastFromNullable(new Cat());
+
+function testUpcastToNullable(animal: Animal): void {
+  var maybeCat = <Cat | null>animal;
+  if (maybeCat) maybeCat.meow();
+}
+testUpcastToNullable(new Cat());
+
+function testUpcastFromToNullable(animal: Animal | null): void {
+  var maybeCat = <Cat | null>animal;
+  if (maybeCat) maybeCat.meow();
+}
+testUpcastFromToNullable(new Cat());
diff --git a/tests/compiler/managed-cast.untouched.wat b/tests/compiler/managed-cast.untouched.wat
new file mode 100644
index 0000000000..e67dc6eab6
--- /dev/null
+++ b/tests/compiler/managed-cast.untouched.wat
@@ -0,0 +1,3725 @@
+(module
+ (type $i32_=>_none (func (param i32)))
+ (type $i32_i32_=>_none (func (param i32 i32)))
+ (type $i32_=>_i32 (func (param i32) (result i32)))
+ (type $none_=>_none (func))
+ (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
+ (type $i32_i32_i32_=>_none (func (param i32 i32 i32)))
+ (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
+ (type $none_=>_i32 (func (result i32)))
+ (type $i32_i32_i32_=>_i32 (func (param i32 i32 i32) (result i32)))
+ (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
+ (import "rtrace" "onfree" (func $~lib/rt/rtrace/onfree (param i32)))
+ (import "rtrace" "onalloc" (func $~lib/rt/rtrace/onalloc (param i32)))
+ (import "rtrace" "onincrement" (func $~lib/rt/rtrace/onincrement (param i32)))
+ (import "rtrace" "ondecrement" (func $~lib/rt/rtrace/ondecrement (param i32)))
+ (memory $0 1)
+ (data (i32.const 16) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00t\00l\00s\00f\00.\00t\00s\00")
+ (data (i32.const 64) "(\00\00\00\01\00\00\00\01\00\00\00(\00\00\00a\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e\00")
+ (data (i32.const 128) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00p\00u\00r\00e\00.\00t\00s\00")
+ (data (i32.const 176) "$\00\00\00\01\00\00\00\01\00\00\00$\00\00\00I\00n\00d\00e\00x\00 \00o\00u\00t\00 \00o\00f\00 \00r\00a\00n\00g\00e\00")
+ (data (i32.const 240) "\14\00\00\00\01\00\00\00\01\00\00\00\14\00\00\00~\00l\00i\00b\00/\00r\00t\00.\00t\00s\00")
+ (data (i32.const 288) "\1e\00\00\00\01\00\00\00\01\00\00\00\1e\00\00\00m\00a\00n\00a\00g\00e\00d\00-\00c\00a\00s\00t\00.\00t\00s\00")
+ (data (i32.const 336) "\05\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\00\00\00\00\10\00\00\00\04\00\00\00\10\00\00\00\00\00\00\00")
+ (table $0 1 funcref)
+ (global $~lib/rt/tlsf/ROOT (mut i32) (i32.const 0))
+ (global $~lib/rt/tlsf/collectLock (mut i32) (i32.const 0))
+ (global $~lib/gc/gc.auto (mut i32) (i32.const 1))
+ (global $~lib/rt/pure/ROOTS (mut i32) (i32.const 0))
+ (global $~lib/rt/pure/CUR (mut i32) (i32.const 0))
+ (global $~lib/rt/pure/END (mut i32) (i32.const 0))
+ (global $~lib/ASC_SHRINK_LEVEL i32 (i32.const 0))
+ (global $~started (mut i32) (i32.const 0))
+ (global $~lib/rt/__rtti_base i32 (i32.const 336))
+ (global $~lib/heap/__heap_base i32 (i32.const 380))
+ (export "_start" (func $~start))
+ (export "memory" (memory $0))
+ (func $~lib/rt/tlsf/removeBlock (; 5 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $8 i32)
+  (local $9 i32)
+  (local $10 i32)
+  (local $11 i32)
+  local.get $1
+  i32.load
+  local.set $2
+  local.get $2
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 277
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $2
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $3
+  local.get $3
+  i32.const 16
+  i32.ge_u
+  if (result i32)
+   local.get $3
+   i32.const 1073741808
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 279
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $4
+   local.get $3
+   i32.const 4
+   i32.shr_u
+   local.set $5
+  else
+   i32.const 31
+   local.get $3
+   i32.clz
+   i32.sub
+   local.set $4
+   local.get $3
+   local.get $4
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $5
+   local.get $4
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $4
+  end
+  local.get $4
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $5
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 292
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load offset=16
+  local.set $6
+  local.get $1
+  i32.load offset=20
+  local.set $7
+  local.get $6
+  if
+   local.get $6
+   local.get $7
+   i32.store offset=20
+  end
+  local.get $7
+  if
+   local.get $7
+   local.get $6
+   i32.store offset=16
+  end
+  local.get $1
+  local.get $0
+  local.set $10
+  local.get $4
+  local.set $9
+  local.get $5
+  local.set $8
+  local.get $10
+  local.get $9
+  i32.const 4
+  i32.shl
+  local.get $8
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=96
+  i32.eq
+  if
+   local.get $0
+   local.set $11
+   local.get $4
+   local.set $10
+   local.get $5
+   local.set $9
+   local.get $7
+   local.set $8
+   local.get $11
+   local.get $10
+   i32.const 4
+   i32.shl
+   local.get $9
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   local.get $8
+   i32.store offset=96
+   local.get $7
+   i32.eqz
+   if
+    local.get $0
+    local.set $9
+    local.get $4
+    local.set $8
+    local.get $9
+    local.get $8
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=4
+    local.set $9
+    local.get $0
+    local.set $8
+    local.get $4
+    local.set $11
+    local.get $9
+    i32.const 1
+    local.get $5
+    i32.shl
+    i32.const -1
+    i32.xor
+    i32.and
+    local.tee $9
+    local.set $10
+    local.get $8
+    local.get $11
+    i32.const 2
+    i32.shl
+    i32.add
+    local.get $10
+    i32.store offset=4
+    local.get $9
+    i32.eqz
+    if
+     local.get $0
+     local.get $0
+     i32.load
+     i32.const 1
+     local.get $4
+     i32.shl
+     i32.const -1
+     i32.xor
+     i32.and
+     i32.store
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/insertBlock (; 6 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $8 i32)
+  (local $9 i32)
+  (local $10 i32)
+  (local $11 i32)
+  (local $12 i32)
+  (local $13 i32)
+  local.get $1
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 205
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.load
+  local.set $2
+  local.get $2
+  i32.const 1
+  i32.and
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 207
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  local.set $3
+  local.get $3
+  i32.const 16
+  i32.add
+  local.get $3
+  i32.load
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.add
+  local.set $4
+  local.get $4
+  i32.load
+  local.set $5
+  local.get $5
+  i32.const 1
+  i32.and
+  if
+   local.get $2
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 16
+   i32.add
+   local.get $5
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   local.set $3
+   local.get $3
+   i32.const 1073741808
+   i32.lt_u
+   if
+    local.get $0
+    local.get $4
+    call $~lib/rt/tlsf/removeBlock
+    local.get $1
+    local.get $2
+    i32.const 3
+    i32.and
+    local.get $3
+    i32.or
+    local.tee $2
+    i32.store
+    local.get $1
+    local.set $6
+    local.get $6
+    i32.const 16
+    i32.add
+    local.get $6
+    i32.load
+    i32.const 3
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.add
+    local.set $4
+    local.get $4
+    i32.load
+    local.set $5
+   end
+  end
+  local.get $2
+  i32.const 2
+  i32.and
+  if
+   local.get $1
+   local.set $6
+   local.get $6
+   i32.const 4
+   i32.sub
+   i32.load
+   local.set $6
+   local.get $6
+   i32.load
+   local.set $3
+   local.get $3
+   i32.const 1
+   i32.and
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 228
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $3
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 16
+   i32.add
+   local.get $2
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   local.set $7
+   local.get $7
+   i32.const 1073741808
+   i32.lt_u
+   if
+    local.get $0
+    local.get $6
+    call $~lib/rt/tlsf/removeBlock
+    local.get $6
+    local.get $3
+    i32.const 3
+    i32.and
+    local.get $7
+    i32.or
+    local.tee $2
+    i32.store
+    local.get $6
+    local.set $1
+   end
+  end
+  local.get $4
+  local.get $5
+  i32.const 2
+  i32.or
+  i32.store
+  local.get $2
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.set $8
+  local.get $8
+  i32.const 16
+  i32.ge_u
+  if (result i32)
+   local.get $8
+   i32.const 1073741808
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 243
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 16
+  i32.add
+  local.get $8
+  i32.add
+  local.get $4
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 244
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $4
+  i32.const 4
+  i32.sub
+  local.get $1
+  i32.store
+  local.get $8
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $9
+   local.get $8
+   i32.const 4
+   i32.shr_u
+   local.set $10
+  else
+   i32.const 31
+   local.get $8
+   i32.clz
+   i32.sub
+   local.set $9
+   local.get $8
+   local.get $9
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $10
+   local.get $9
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $9
+  end
+  local.get $9
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $10
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 260
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.set $7
+  local.get $9
+  local.set $3
+  local.get $10
+  local.set $6
+  local.get $7
+  local.get $3
+  i32.const 4
+  i32.shl
+  local.get $6
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=96
+  local.set $11
+  local.get $1
+  i32.const 0
+  i32.store offset=16
+  local.get $1
+  local.get $11
+  i32.store offset=20
+  local.get $11
+  if
+   local.get $11
+   local.get $1
+   i32.store offset=16
+  end
+  local.get $0
+  local.set $12
+  local.get $9
+  local.set $7
+  local.get $10
+  local.set $3
+  local.get $1
+  local.set $6
+  local.get $12
+  local.get $7
+  i32.const 4
+  i32.shl
+  local.get $3
+  i32.add
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $6
+  i32.store offset=96
+  local.get $0
+  local.get $0
+  i32.load
+  i32.const 1
+  local.get $9
+  i32.shl
+  i32.or
+  i32.store
+  local.get $0
+  local.set $13
+  local.get $9
+  local.set $12
+  local.get $0
+  local.set $3
+  local.get $9
+  local.set $6
+  local.get $3
+  local.get $6
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=4
+  i32.const 1
+  local.get $10
+  i32.shl
+  i32.or
+  local.set $7
+  local.get $13
+  local.get $12
+  i32.const 2
+  i32.shl
+  i32.add
+  local.get $7
+  i32.store offset=4
+ )
+ (func $~lib/rt/tlsf/addMemory (; 7 ;) (param $0 i32) (param $1 i32) (param $2 i32) (result i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $8 i32)
+  (local $9 i32)
+  local.get $1
+  local.get $2
+  i32.le_u
+  if (result i32)
+   local.get $1
+   i32.const 15
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  if (result i32)
+   local.get $2
+   i32.const 15
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 386
+   i32.const 4
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.set $3
+  local.get $3
+  i32.load offset=1568
+  local.set $4
+  i32.const 0
+  local.set $5
+  local.get $4
+  if
+   local.get $1
+   local.get $4
+   i32.const 16
+   i32.add
+   i32.ge_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 396
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $1
+   i32.const 16
+   i32.sub
+   local.get $4
+   i32.eq
+   if
+    local.get $1
+    i32.const 16
+    i32.sub
+    local.set $1
+    local.get $4
+    i32.load
+    local.set $5
+   else
+    nop
+   end
+  else
+   local.get $1
+   local.get $0
+   i32.const 1572
+   i32.add
+   i32.ge_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 32
+    i32.const 408
+    i32.const 4
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+  local.get $2
+  local.get $1
+  i32.sub
+  local.set $6
+  local.get $6
+  i32.const 48
+  i32.lt_u
+  if
+   i32.const 0
+   return
+  end
+  local.get $6
+  i32.const 16
+  i32.const 1
+  i32.shl
+  i32.sub
+  local.set $7
+  local.get $1
+  local.set $8
+  local.get $8
+  local.get $7
+  i32.const 1
+  i32.or
+  local.get $5
+  i32.const 2
+  i32.and
+  i32.or
+  i32.store
+  local.get $8
+  i32.const 0
+  i32.store offset=16
+  local.get $8
+  i32.const 0
+  i32.store offset=20
+  local.get $1
+  local.get $6
+  i32.add
+  i32.const 16
+  i32.sub
+  local.set $4
+  local.get $4
+  i32.const 0
+  i32.const 2
+  i32.or
+  i32.store
+  local.get $0
+  local.set $9
+  local.get $4
+  local.set $3
+  local.get $9
+  local.get $3
+  i32.store offset=1568
+  local.get $0
+  local.get $8
+  call $~lib/rt/tlsf/insertBlock
+  i32.const 1
+ )
+ (func $~lib/rt/tlsf/maybeInitialize (; 8 ;) (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $8 i32)
+  (local $9 i32)
+  (local $10 i32)
+  (local $11 i32)
+  global.get $~lib/rt/tlsf/ROOT
+  local.set $0
+  local.get $0
+  i32.eqz
+  if
+   global.get $~lib/heap/__heap_base
+   i32.const 15
+   i32.add
+   i32.const -16
+   i32.and
+   local.set $1
+   memory.size
+   local.set $2
+   local.get $1
+   i32.const 1572
+   i32.add
+   i32.const 65535
+   i32.add
+   i32.const 65535
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 16
+   i32.shr_u
+   local.set $3
+   local.get $3
+   local.get $2
+   i32.gt_s
+   if (result i32)
+    local.get $3
+    local.get $2
+    i32.sub
+    memory.grow
+    i32.const 0
+    i32.lt_s
+   else
+    i32.const 0
+   end
+   if
+    unreachable
+   end
+   local.get $1
+   local.set $0
+   local.get $0
+   i32.const 0
+   i32.store
+   local.get $0
+   local.set $5
+   i32.const 0
+   local.set $4
+   local.get $5
+   local.get $4
+   i32.store offset=1568
+   i32.const 0
+   local.set $5
+   loop $for-loop|0
+    local.get $5
+    i32.const 23
+    i32.lt_u
+    local.set $4
+    local.get $4
+    if
+     local.get $0
+     local.set $8
+     local.get $5
+     local.set $7
+     i32.const 0
+     local.set $6
+     local.get $8
+     local.get $7
+     i32.const 2
+     i32.shl
+     i32.add
+     local.get $6
+     i32.store offset=4
+     i32.const 0
+     local.set $8
+     loop $for-loop|1
+      local.get $8
+      i32.const 16
+      i32.lt_u
+      local.set $7
+      local.get $7
+      if
+       local.get $0
+       local.set $11
+       local.get $5
+       local.set $10
+       local.get $8
+       local.set $9
+       i32.const 0
+       local.set $6
+       local.get $11
+       local.get $10
+       i32.const 4
+       i32.shl
+       local.get $9
+       i32.add
+       i32.const 2
+       i32.shl
+       i32.add
+       local.get $6
+       i32.store offset=96
+       local.get $8
+       i32.const 1
+       i32.add
+       local.set $8
+       br $for-loop|1
+      end
+     end
+     local.get $5
+     i32.const 1
+     i32.add
+     local.set $5
+     br $for-loop|0
+    end
+   end
+   local.get $0
+   local.get $1
+   i32.const 1572
+   i32.add
+   i32.const 15
+   i32.add
+   i32.const 15
+   i32.const -1
+   i32.xor
+   i32.and
+   memory.size
+   i32.const 16
+   i32.shl
+   call $~lib/rt/tlsf/addMemory
+   drop
+   local.get $0
+   global.set $~lib/rt/tlsf/ROOT
+  end
+  local.get $0
+ )
+ (func $~lib/rt/tlsf/prepareSize (; 9 ;) (param $0 i32) (result i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  i32.const 1073741808
+  i32.ge_u
+  if
+   i32.const 80
+   i32.const 32
+   i32.const 457
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  i32.const 15
+  i32.add
+  i32.const 15
+  i32.const -1
+  i32.xor
+  i32.and
+  local.tee $1
+  i32.const 16
+  local.tee $2
+  local.get $1
+  local.get $2
+  i32.gt_u
+  select
+ )
+ (func $~lib/rt/tlsf/searchBlock (; 10 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  (local $8 i32)
+  (local $9 i32)
+  local.get $1
+  i32.const 256
+  i32.lt_u
+  if
+   i32.const 0
+   local.set $2
+   local.get $1
+   i32.const 4
+   i32.shr_u
+   local.set $3
+  else
+   local.get $1
+   i32.const 536870904
+   i32.lt_u
+   if (result i32)
+    local.get $1
+    i32.const 1
+    i32.const 27
+    local.get $1
+    i32.clz
+    i32.sub
+    i32.shl
+    i32.add
+    i32.const 1
+    i32.sub
+   else
+    local.get $1
+   end
+   local.set $4
+   i32.const 31
+   local.get $4
+   i32.clz
+   i32.sub
+   local.set $2
+   local.get $4
+   local.get $2
+   i32.const 4
+   i32.sub
+   i32.shr_u
+   i32.const 1
+   i32.const 4
+   i32.shl
+   i32.xor
+   local.set $3
+   local.get $2
+   i32.const 8
+   i32.const 1
+   i32.sub
+   i32.sub
+   local.set $2
+  end
+  local.get $2
+  i32.const 23
+  i32.lt_u
+  if (result i32)
+   local.get $3
+   i32.const 16
+   i32.lt_u
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 338
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.set $5
+  local.get $2
+  local.set $4
+  local.get $5
+  local.get $4
+  i32.const 2
+  i32.shl
+  i32.add
+  i32.load offset=4
+  i32.const 0
+  i32.const -1
+  i32.xor
+  local.get $3
+  i32.shl
+  i32.and
+  local.set $6
+  i32.const 0
+  local.set $7
+  local.get $6
+  i32.eqz
+  if
+   local.get $0
+   i32.load
+   i32.const 0
+   i32.const -1
+   i32.xor
+   local.get $2
+   i32.const 1
+   i32.add
+   i32.shl
+   i32.and
+   local.set $5
+   local.get $5
+   i32.eqz
+   if
+    i32.const 0
+    local.set $7
+   else
+    local.get $5
+    i32.ctz
+    local.set $2
+    local.get $0
+    local.set $8
+    local.get $2
+    local.set $4
+    local.get $8
+    local.get $4
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=4
+    local.set $6
+    local.get $6
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 32
+     i32.const 351
+     i32.const 17
+     call $~lib/builtins/abort
+     unreachable
+    end
+    local.get $0
+    local.set $9
+    local.get $2
+    local.set $8
+    local.get $6
+    i32.ctz
+    local.set $4
+    local.get $9
+    local.get $8
+    i32.const 4
+    i32.shl
+    local.get $4
+    i32.add
+    i32.const 2
+    i32.shl
+    i32.add
+    i32.load offset=96
+    local.set $7
+   end
+  else
+   local.get $0
+   local.set $9
+   local.get $2
+   local.set $8
+   local.get $6
+   i32.ctz
+   local.set $4
+   local.get $9
+   local.get $8
+   i32.const 4
+   i32.shl
+   local.get $4
+   i32.add
+   i32.const 2
+   i32.shl
+   i32.add
+   i32.load offset=96
+   local.set $7
+  end
+  local.get $7
+ )
+ (func $~lib/rt/pure/markGray (; 11 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.set $1
+  local.get $1
+  i32.const 1879048192
+  i32.and
+  i32.const 268435456
+  i32.ne
+  if
+   local.get $0
+   local.get $1
+   i32.const 1879048192
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 268435456
+   i32.or
+   i32.store offset=4
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 2
+   call $~lib/rt/__visit_members
+  end
+ )
+ (func $~lib/rt/tlsf/freeBlock (; 12 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  local.get $1
+  i32.load
+  local.set $2
+  local.get $2
+  i32.const 1
+  i32.and
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 569
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  local.get $2
+  i32.const 1
+  i32.or
+  i32.store
+  local.get $0
+  local.get $1
+  call $~lib/rt/tlsf/insertBlock
+  local.get $1
+  call $~lib/rt/rtrace/onfree
+ )
+ (func $~lib/rt/pure/scanBlack (; 13 ;) (param $0 i32)
+  local.get $0
+  local.get $0
+  i32.load offset=4
+  i32.const 1879048192
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.const 0
+  i32.or
+  i32.store offset=4
+  local.get $0
+  i32.const 16
+  i32.add
+  i32.const 4
+  call $~lib/rt/__visit_members
+ )
+ (func $~lib/rt/pure/scan (; 14 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.set $1
+  local.get $1
+  i32.const 1879048192
+  i32.and
+  i32.const 268435456
+  i32.eq
+  if
+   local.get $1
+   i32.const 268435455
+   i32.and
+   i32.const 0
+   i32.gt_u
+   if
+    local.get $0
+    call $~lib/rt/pure/scanBlack
+   else
+    local.get $0
+    local.get $1
+    i32.const 1879048192
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.const 536870912
+    i32.or
+    i32.store offset=4
+    local.get $0
+    i32.const 16
+    i32.add
+    i32.const 3
+    call $~lib/rt/__visit_members
+   end
+  end
+ )
+ (func $~lib/rt/pure/collectWhite (; 15 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.set $1
+  local.get $1
+  i32.const 1879048192
+  i32.and
+  i32.const 536870912
+  i32.eq
+  if (result i32)
+   local.get $1
+   i32.const -2147483648
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  if
+   local.get $0
+   local.get $1
+   i32.const 1879048192
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.const 0
+   i32.or
+   i32.store offset=4
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 5
+   call $~lib/rt/__visit_members
+   global.get $~lib/rt/tlsf/ROOT
+   local.get $0
+   call $~lib/rt/tlsf/freeBlock
+  end
+ )
+ (func $~lib/rt/pure/__collect (; 16 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  global.get $~lib/rt/pure/ROOTS
+  local.set $0
+  local.get $0
+  local.set $1
+  local.get $1
+  local.set $2
+  global.get $~lib/rt/pure/CUR
+  local.set $3
+  loop $for-loop|0
+   local.get $2
+   local.get $3
+   i32.lt_u
+   local.set $4
+   local.get $4
+   if
+    local.get $2
+    i32.load
+    local.set $5
+    local.get $5
+    i32.load offset=4
+    local.set $6
+    local.get $6
+    i32.const 1879048192
+    i32.and
+    i32.const 805306368
+    i32.eq
+    if (result i32)
+     local.get $6
+     i32.const 268435455
+     i32.and
+     i32.const 0
+     i32.gt_u
+    else
+     i32.const 0
+    end
+    if
+     local.get $5
+     call $~lib/rt/pure/markGray
+     local.get $1
+     local.get $5
+     i32.store
+     local.get $1
+     i32.const 4
+     i32.add
+     local.set $1
+    else
+     local.get $6
+     i32.const 1879048192
+     i32.and
+     i32.const 0
+     i32.eq
+     if (result i32)
+      local.get $6
+      i32.const 268435455
+      i32.and
+      i32.eqz
+     else
+      i32.const 0
+     end
+     if
+      global.get $~lib/rt/tlsf/ROOT
+      local.get $5
+      call $~lib/rt/tlsf/freeBlock
+     else
+      local.get $5
+      local.get $6
+      i32.const -2147483648
+      i32.const -1
+      i32.xor
+      i32.and
+      i32.store offset=4
+     end
+    end
+    local.get $2
+    i32.const 4
+    i32.add
+    local.set $2
+    br $for-loop|0
+   end
+  end
+  local.get $1
+  global.set $~lib/rt/pure/CUR
+  local.get $0
+  local.set $3
+  loop $for-loop|1
+   local.get $3
+   local.get $1
+   i32.lt_u
+   local.set $2
+   local.get $2
+   if
+    local.get $3
+    i32.load
+    call $~lib/rt/pure/scan
+    local.get $3
+    i32.const 4
+    i32.add
+    local.set $3
+    br $for-loop|1
+   end
+  end
+  local.get $0
+  local.set $3
+  loop $for-loop|2
+   local.get $3
+   local.get $1
+   i32.lt_u
+   local.set $2
+   local.get $2
+   if
+    local.get $3
+    i32.load
+    local.set $4
+    local.get $4
+    local.get $4
+    i32.load offset=4
+    i32.const -2147483648
+    i32.const -1
+    i32.xor
+    i32.and
+    i32.store offset=4
+    local.get $4
+    call $~lib/rt/pure/collectWhite
+    local.get $3
+    i32.const 4
+    i32.add
+    local.set $3
+    br $for-loop|2
+   end
+  end
+  local.get $0
+  global.set $~lib/rt/pure/CUR
+ )
+ (func $~lib/rt/tlsf/growMemory (; 17 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  local.get $1
+  i32.const 536870904
+  i32.lt_u
+  if
+   local.get $1
+   i32.const 1
+   i32.const 27
+   local.get $1
+   i32.clz
+   i32.sub
+   i32.shl
+   i32.const 1
+   i32.sub
+   i32.add
+   local.set $1
+  end
+  memory.size
+  local.set $2
+  local.get $1
+  i32.const 16
+  local.get $2
+  i32.const 16
+  i32.shl
+  i32.const 16
+  i32.sub
+  local.get $0
+  local.set $3
+  local.get $3
+  i32.load offset=1568
+  i32.ne
+  i32.shl
+  i32.add
+  local.set $1
+  local.get $1
+  i32.const 65535
+  i32.add
+  i32.const 65535
+  i32.const -1
+  i32.xor
+  i32.and
+  i32.const 16
+  i32.shr_u
+  local.set $4
+  local.get $2
+  local.tee $3
+  local.get $4
+  local.tee $5
+  local.get $3
+  local.get $5
+  i32.gt_s
+  select
+  local.set $6
+  local.get $6
+  memory.grow
+  i32.const 0
+  i32.lt_s
+  if
+   local.get $4
+   memory.grow
+   i32.const 0
+   i32.lt_s
+   if
+    unreachable
+   end
+  end
+  memory.size
+  local.set $7
+  local.get $0
+  local.get $2
+  i32.const 16
+  i32.shl
+  local.get $7
+  i32.const 16
+  i32.shl
+  call $~lib/rt/tlsf/addMemory
+  drop
+ )
+ (func $~lib/rt/tlsf/prepareBlock (; 18 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  local.get $1
+  i32.load
+  local.set $3
+  local.get $2
+  i32.const 15
+  i32.and
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 365
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const 3
+  i32.const -1
+  i32.xor
+  i32.and
+  local.get $2
+  i32.sub
+  local.set $4
+  local.get $4
+  i32.const 32
+  i32.ge_u
+  if
+   local.get $1
+   local.get $2
+   local.get $3
+   i32.const 2
+   i32.and
+   i32.or
+   i32.store
+   local.get $1
+   i32.const 16
+   i32.add
+   local.get $2
+   i32.add
+   local.set $5
+   local.get $5
+   local.get $4
+   i32.const 16
+   i32.sub
+   i32.const 1
+   i32.or
+   i32.store
+   local.get $0
+   local.get $5
+   call $~lib/rt/tlsf/insertBlock
+  else
+   local.get $1
+   local.get $3
+   i32.const 1
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.store
+   local.get $1
+   local.set $5
+   local.get $5
+   i32.const 16
+   i32.add
+   local.get $5
+   i32.load
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   local.get $1
+   local.set $5
+   local.get $5
+   i32.const 16
+   i32.add
+   local.get $5
+   i32.load
+   i32.const 3
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.add
+   i32.load
+   i32.const 2
+   i32.const -1
+   i32.xor
+   i32.and
+   i32.store
+  end
+ )
+ (func $~lib/rt/tlsf/allocateBlock (; 19 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  (local $3 i32)
+  global.get $~lib/rt/tlsf/collectLock
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 490
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  call $~lib/rt/tlsf/prepareSize
+  local.set $2
+  local.get $0
+  local.get $2
+  call $~lib/rt/tlsf/searchBlock
+  local.set $3
+  local.get $3
+  i32.eqz
+  if
+   global.get $~lib/gc/gc.auto
+   if
+    i32.const 1
+    global.set $~lib/rt/tlsf/collectLock
+    call $~lib/rt/pure/__collect
+    i32.const 0
+    global.set $~lib/rt/tlsf/collectLock
+    local.get $0
+    local.get $2
+    call $~lib/rt/tlsf/searchBlock
+    local.set $3
+    local.get $3
+    i32.eqz
+    if
+     local.get $0
+     local.get $2
+     call $~lib/rt/tlsf/growMemory
+     local.get $0
+     local.get $2
+     call $~lib/rt/tlsf/searchBlock
+     local.set $3
+     local.get $3
+     i32.eqz
+     if
+      i32.const 0
+      i32.const 32
+      i32.const 502
+      i32.const 19
+      call $~lib/builtins/abort
+      unreachable
+     end
+    end
+   else
+    local.get $0
+    local.get $2
+    call $~lib/rt/tlsf/growMemory
+    local.get $0
+    local.get $2
+    call $~lib/rt/tlsf/searchBlock
+    local.set $3
+    local.get $3
+    i32.eqz
+    if
+     i32.const 0
+     i32.const 32
+     i32.const 507
+     i32.const 17
+     call $~lib/builtins/abort
+     unreachable
+    end
+   end
+  end
+  local.get $3
+  i32.load
+  i32.const -4
+  i32.and
+  local.get $2
+  i32.ge_u
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 510
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $3
+  i32.const 0
+  i32.store offset=4
+  local.get $3
+  local.get $1
+  i32.store offset=12
+  local.get $0
+  local.get $3
+  call $~lib/rt/tlsf/removeBlock
+  local.get $0
+  local.get $3
+  local.get $2
+  call $~lib/rt/tlsf/prepareBlock
+  local.get $3
+  call $~lib/rt/rtrace/onalloc
+  local.get $3
+ )
+ (func $~lib/rt/tlsf/__alloc (; 20 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  call $~lib/rt/tlsf/maybeInitialize
+  local.get $0
+  call $~lib/rt/tlsf/allocateBlock
+  local.set $2
+  local.get $2
+  local.get $1
+  i32.store offset=8
+  local.get $2
+  i32.const 16
+  i32.add
+ )
+ (func $~lib/rt/pure/increment (; 21 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  i32.load offset=4
+  local.set $1
+  local.get $1
+  i32.const -268435456
+  i32.and
+  local.get $1
+  i32.const 1
+  i32.add
+  i32.const -268435456
+  i32.and
+  i32.eq
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 104
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $0
+  local.get $1
+  i32.const 1
+  i32.add
+  i32.store offset=4
+  local.get $0
+  call $~lib/rt/rtrace/onincrement
+  local.get $0
+  i32.load
+  i32.const 1
+  i32.and
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 107
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+ )
+ (func $~lib/rt/pure/__retain (; 22 ;) (param $0 i32) (result i32)
+  local.get $0
+  global.get $~lib/heap/__heap_base
+  i32.gt_u
+  if
+   local.get $0
+   i32.const 16
+   i32.sub
+   call $~lib/rt/pure/increment
+  end
+  local.get $0
+ )
+ (func $managed-cast/Animal#constructor (; 23 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 4
+   call $~lib/rt/tlsf/__alloc
+   call $~lib/rt/pure/__retain
+   local.set $0
+  end
+  local.get $0
+ )
+ (func $managed-cast/Cat#constructor (; 24 ;) (param $0 i32) (result i32)
+  local.get $0
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 3
+   call $~lib/rt/tlsf/__alloc
+   call $~lib/rt/pure/__retain
+   local.set $0
+  end
+  local.get $0
+  call $managed-cast/Animal#constructor
+  local.set $0
+  local.get $0
+ )
+ (func $managed-cast/Animal#tame (; 25 ;) (param $0 i32)
+  nop
+ )
+ (func $~lib/rt/__typeinfo (; 26 ;) (param $0 i32) (result i32)
+  (local $1 i32)
+  global.get $~lib/rt/__rtti_base
+  local.set $1
+  local.get $0
+  local.get $1
+  i32.load
+  i32.gt_u
+  if
+   i32.const 192
+   i32.const 256
+   i32.const 22
+   i32.const 27
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $1
+  i32.const 4
+  i32.add
+  local.get $0
+  i32.const 8
+  i32.mul
+  i32.add
+  i32.load
+ )
+ (func $~lib/util/memory/memcpy (; 27 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  loop $while-continue|0
+   local.get $2
+   if (result i32)
+    local.get $1
+    i32.const 3
+    i32.and
+   else
+    i32.const 0
+   end
+   local.set $5
+   local.get $5
+   if
+    local.get $0
+    local.tee $6
+    i32.const 1
+    i32.add
+    local.set $0
+    local.get $6
+    local.get $1
+    local.tee $6
+    i32.const 1
+    i32.add
+    local.set $1
+    local.get $6
+    i32.load8_u
+    i32.store8
+    local.get $2
+    i32.const 1
+    i32.sub
+    local.set $2
+    br $while-continue|0
+   end
+  end
+  local.get $0
+  i32.const 3
+  i32.and
+  i32.const 0
+  i32.eq
+  if
+   loop $while-continue|1
+    local.get $2
+    i32.const 16
+    i32.ge_u
+    local.set $5
+    local.get $5
+    if
+     local.get $0
+     local.get $1
+     i32.load
+     i32.store
+     local.get $0
+     i32.const 4
+     i32.add
+     local.get $1
+     i32.const 4
+     i32.add
+     i32.load
+     i32.store
+     local.get $0
+     i32.const 8
+     i32.add
+     local.get $1
+     i32.const 8
+     i32.add
+     i32.load
+     i32.store
+     local.get $0
+     i32.const 12
+     i32.add
+     local.get $1
+     i32.const 12
+     i32.add
+     i32.load
+     i32.store
+     local.get $1
+     i32.const 16
+     i32.add
+     local.set $1
+     local.get $0
+     i32.const 16
+     i32.add
+     local.set $0
+     local.get $2
+     i32.const 16
+     i32.sub
+     local.set $2
+     br $while-continue|1
+    end
+   end
+   local.get $2
+   i32.const 8
+   i32.and
+   if
+    local.get $0
+    local.get $1
+    i32.load
+    i32.store
+    local.get $0
+    i32.const 4
+    i32.add
+    local.get $1
+    i32.const 4
+    i32.add
+    i32.load
+    i32.store
+    local.get $0
+    i32.const 8
+    i32.add
+    local.set $0
+    local.get $1
+    i32.const 8
+    i32.add
+    local.set $1
+   end
+   local.get $2
+   i32.const 4
+   i32.and
+   if
+    local.get $0
+    local.get $1
+    i32.load
+    i32.store
+    local.get $0
+    i32.const 4
+    i32.add
+    local.set $0
+    local.get $1
+    i32.const 4
+    i32.add
+    local.set $1
+   end
+   local.get $2
+   i32.const 2
+   i32.and
+   if
+    local.get $0
+    local.get $1
+    i32.load16_u
+    i32.store16
+    local.get $0
+    i32.const 2
+    i32.add
+    local.set $0
+    local.get $1
+    i32.const 2
+    i32.add
+    local.set $1
+   end
+   local.get $2
+   i32.const 1
+   i32.and
+   if
+    local.get $0
+    local.tee $5
+    i32.const 1
+    i32.add
+    local.set $0
+    local.get $5
+    local.get $1
+    local.tee $5
+    i32.const 1
+    i32.add
+    local.set $1
+    local.get $5
+    i32.load8_u
+    i32.store8
+   end
+   return
+  end
+  local.get $2
+  i32.const 32
+  i32.ge_u
+  if
+   block $break|2
+    block $case2|2
+     block $case1|2
+      block $case0|2
+       local.get $0
+       i32.const 3
+       i32.and
+       local.set $5
+       local.get $5
+       i32.const 1
+       i32.eq
+       br_if $case0|2
+       local.get $5
+       i32.const 2
+       i32.eq
+       br_if $case1|2
+       local.get $5
+       i32.const 3
+       i32.eq
+       br_if $case2|2
+       br $break|2
+      end
+      local.get $1
+      i32.load
+      local.set $3
+      local.get $0
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $0
+      local.get $5
+      local.get $1
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $1
+      local.get $5
+      i32.load8_u
+      i32.store8
+      local.get $0
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $0
+      local.get $5
+      local.get $1
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $1
+      local.get $5
+      i32.load8_u
+      i32.store8
+      local.get $0
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $0
+      local.get $5
+      local.get $1
+      local.tee $5
+      i32.const 1
+      i32.add
+      local.set $1
+      local.get $5
+      i32.load8_u
+      i32.store8
+      local.get $2
+      i32.const 3
+      i32.sub
+      local.set $2
+      loop $while-continue|3
+       local.get $2
+       i32.const 17
+       i32.ge_u
+       local.set $5
+       local.get $5
+       if
+        local.get $1
+        i32.const 1
+        i32.add
+        i32.load
+        local.set $4
+        local.get $0
+        local.get $3
+        i32.const 24
+        i32.shr_u
+        local.get $4
+        i32.const 8
+        i32.shl
+        i32.or
+        i32.store
+        local.get $1
+        i32.const 5
+        i32.add
+        i32.load
+        local.set $3
+        local.get $0
+        i32.const 4
+        i32.add
+        local.get $4
+        i32.const 24
+        i32.shr_u
+        local.get $3
+        i32.const 8
+        i32.shl
+        i32.or
+        i32.store
+        local.get $1
+        i32.const 9
+        i32.add
+        i32.load
+        local.set $4
+        local.get $0
+        i32.const 8
+        i32.add
+        local.get $3
+        i32.const 24
+        i32.shr_u
+        local.get $4
+        i32.const 8
+        i32.shl
+        i32.or
+        i32.store
+        local.get $1
+        i32.const 13
+        i32.add
+        i32.load
+        local.set $3
+        local.get $0
+        i32.const 12
+        i32.add
+        local.get $4
+        i32.const 24
+        i32.shr_u
+        local.get $3
+        i32.const 8
+        i32.shl
+        i32.or
+        i32.store
+        local.get $1
+        i32.const 16
+        i32.add
+        local.set $1
+        local.get $0
+        i32.const 16
+        i32.add
+        local.set $0
+        local.get $2
+        i32.const 16
+        i32.sub
+        local.set $2
+        br $while-continue|3
+       end
+      end
+      br $break|2
+     end
+     local.get $1
+     i32.load
+     local.set $3
+     local.get $0
+     local.tee $5
+     i32.const 1
+     i32.add
+     local.set $0
+     local.get $5
+     local.get $1
+     local.tee $5
+     i32.const 1
+     i32.add
+     local.set $1
+     local.get $5
+     i32.load8_u
+     i32.store8
+     local.get $0
+     local.tee $5
+     i32.const 1
+     i32.add
+     local.set $0
+     local.get $5
+     local.get $1
+     local.tee $5
+     i32.const 1
+     i32.add
+     local.set $1
+     local.get $5
+     i32.load8_u
+     i32.store8
+     local.get $2
+     i32.const 2
+     i32.sub
+     local.set $2
+     loop $while-continue|4
+      local.get $2
+      i32.const 18
+      i32.ge_u
+      local.set $5
+      local.get $5
+      if
+       local.get $1
+       i32.const 2
+       i32.add
+       i32.load
+       local.set $4
+       local.get $0
+       local.get $3
+       i32.const 16
+       i32.shr_u
+       local.get $4
+       i32.const 16
+       i32.shl
+       i32.or
+       i32.store
+       local.get $1
+       i32.const 6
+       i32.add
+       i32.load
+       local.set $3
+       local.get $0
+       i32.const 4
+       i32.add
+       local.get $4
+       i32.const 16
+       i32.shr_u
+       local.get $3
+       i32.const 16
+       i32.shl
+       i32.or
+       i32.store
+       local.get $1
+       i32.const 10
+       i32.add
+       i32.load
+       local.set $4
+       local.get $0
+       i32.const 8
+       i32.add
+       local.get $3
+       i32.const 16
+       i32.shr_u
+       local.get $4
+       i32.const 16
+       i32.shl
+       i32.or
+       i32.store
+       local.get $1
+       i32.const 14
+       i32.add
+       i32.load
+       local.set $3
+       local.get $0
+       i32.const 12
+       i32.add
+       local.get $4
+       i32.const 16
+       i32.shr_u
+       local.get $3
+       i32.const 16
+       i32.shl
+       i32.or
+       i32.store
+       local.get $1
+       i32.const 16
+       i32.add
+       local.set $1
+       local.get $0
+       i32.const 16
+       i32.add
+       local.set $0
+       local.get $2
+       i32.const 16
+       i32.sub
+       local.set $2
+       br $while-continue|4
+      end
+     end
+     br $break|2
+    end
+    local.get $1
+    i32.load
+    local.set $3
+    local.get $0
+    local.tee $5
+    i32.const 1
+    i32.add
+    local.set $0
+    local.get $5
+    local.get $1
+    local.tee $5
+    i32.const 1
+    i32.add
+    local.set $1
+    local.get $5
+    i32.load8_u
+    i32.store8
+    local.get $2
+    i32.const 1
+    i32.sub
+    local.set $2
+    loop $while-continue|5
+     local.get $2
+     i32.const 19
+     i32.ge_u
+     local.set $5
+     local.get $5
+     if
+      local.get $1
+      i32.const 3
+      i32.add
+      i32.load
+      local.set $4
+      local.get $0
+      local.get $3
+      i32.const 8
+      i32.shr_u
+      local.get $4
+      i32.const 24
+      i32.shl
+      i32.or
+      i32.store
+      local.get $1
+      i32.const 7
+      i32.add
+      i32.load
+      local.set $3
+      local.get $0
+      i32.const 4
+      i32.add
+      local.get $4
+      i32.const 8
+      i32.shr_u
+      local.get $3
+      i32.const 24
+      i32.shl
+      i32.or
+      i32.store
+      local.get $1
+      i32.const 11
+      i32.add
+      i32.load
+      local.set $4
+      local.get $0
+      i32.const 8
+      i32.add
+      local.get $3
+      i32.const 8
+      i32.shr_u
+      local.get $4
+      i32.const 24
+      i32.shl
+      i32.or
+      i32.store
+      local.get $1
+      i32.const 15
+      i32.add
+      i32.load
+      local.set $3
+      local.get $0
+      i32.const 12
+      i32.add
+      local.get $4
+      i32.const 8
+      i32.shr_u
+      local.get $3
+      i32.const 24
+      i32.shl
+      i32.or
+      i32.store
+      local.get $1
+      i32.const 16
+      i32.add
+      local.set $1
+      local.get $0
+      i32.const 16
+      i32.add
+      local.set $0
+      local.get $2
+      i32.const 16
+      i32.sub
+      local.set $2
+      br $while-continue|5
+     end
+    end
+    br $break|2
+   end
+  end
+  local.get $2
+  i32.const 16
+  i32.and
+  if
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+  end
+  local.get $2
+  i32.const 8
+  i32.and
+  if
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+  end
+  local.get $2
+  i32.const 4
+  i32.and
+  if
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+  end
+  local.get $2
+  i32.const 2
+  i32.and
+  if
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+  end
+  local.get $2
+  i32.const 1
+  i32.and
+  if
+   local.get $0
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $0
+   local.get $5
+   local.get $1
+   local.tee $5
+   i32.const 1
+   i32.add
+   local.set $1
+   local.get $5
+   i32.load8_u
+   i32.store8
+  end
+ )
+ (func $~lib/memory/memory.copy (; 28 ;) (param $0 i32) (param $1 i32) (param $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  block $~lib/util/memory/memmove|inlined.0
+   local.get $0
+   local.set $5
+   local.get $1
+   local.set $4
+   local.get $2
+   local.set $3
+   local.get $5
+   local.get $4
+   i32.eq
+   if
+    br $~lib/util/memory/memmove|inlined.0
+   end
+   local.get $4
+   local.get $3
+   i32.add
+   local.get $5
+   i32.le_u
+   if (result i32)
+    i32.const 1
+   else
+    local.get $5
+    local.get $3
+    i32.add
+    local.get $4
+    i32.le_u
+   end
+   if
+    local.get $5
+    local.get $4
+    local.get $3
+    call $~lib/util/memory/memcpy
+    br $~lib/util/memory/memmove|inlined.0
+   end
+   local.get $5
+   local.get $4
+   i32.lt_u
+   if
+    local.get $4
+    i32.const 7
+    i32.and
+    local.get $5
+    i32.const 7
+    i32.and
+    i32.eq
+    if
+     loop $while-continue|0
+      local.get $5
+      i32.const 7
+      i32.and
+      local.set $6
+      local.get $6
+      if
+       local.get $3
+       i32.eqz
+       if
+        br $~lib/util/memory/memmove|inlined.0
+       end
+       local.get $3
+       i32.const 1
+       i32.sub
+       local.set $3
+       local.get $5
+       local.tee $7
+       i32.const 1
+       i32.add
+       local.set $5
+       local.get $7
+       local.get $4
+       local.tee $7
+       i32.const 1
+       i32.add
+       local.set $4
+       local.get $7
+       i32.load8_u
+       i32.store8
+       br $while-continue|0
+      end
+     end
+     loop $while-continue|1
+      local.get $3
+      i32.const 8
+      i32.ge_u
+      local.set $6
+      local.get $6
+      if
+       local.get $5
+       local.get $4
+       i64.load
+       i64.store
+       local.get $3
+       i32.const 8
+       i32.sub
+       local.set $3
+       local.get $5
+       i32.const 8
+       i32.add
+       local.set $5
+       local.get $4
+       i32.const 8
+       i32.add
+       local.set $4
+       br $while-continue|1
+      end
+     end
+    end
+    loop $while-continue|2
+     local.get $3
+     local.set $6
+     local.get $6
+     if
+      local.get $5
+      local.tee $7
+      i32.const 1
+      i32.add
+      local.set $5
+      local.get $7
+      local.get $4
+      local.tee $7
+      i32.const 1
+      i32.add
+      local.set $4
+      local.get $7
+      i32.load8_u
+      i32.store8
+      local.get $3
+      i32.const 1
+      i32.sub
+      local.set $3
+      br $while-continue|2
+     end
+    end
+   else
+    local.get $4
+    i32.const 7
+    i32.and
+    local.get $5
+    i32.const 7
+    i32.and
+    i32.eq
+    if
+     loop $while-continue|3
+      local.get $5
+      local.get $3
+      i32.add
+      i32.const 7
+      i32.and
+      local.set $6
+      local.get $6
+      if
+       local.get $3
+       i32.eqz
+       if
+        br $~lib/util/memory/memmove|inlined.0
+       end
+       local.get $5
+       local.get $3
+       i32.const 1
+       i32.sub
+       local.tee $3
+       i32.add
+       local.get $4
+       local.get $3
+       i32.add
+       i32.load8_u
+       i32.store8
+       br $while-continue|3
+      end
+     end
+     loop $while-continue|4
+      local.get $3
+      i32.const 8
+      i32.ge_u
+      local.set $6
+      local.get $6
+      if
+       local.get $3
+       i32.const 8
+       i32.sub
+       local.set $3
+       local.get $5
+       local.get $3
+       i32.add
+       local.get $4
+       local.get $3
+       i32.add
+       i64.load
+       i64.store
+       br $while-continue|4
+      end
+     end
+    end
+    loop $while-continue|5
+     local.get $3
+     local.set $6
+     local.get $6
+     if
+      local.get $5
+      local.get $3
+      i32.const 1
+      i32.sub
+      local.tee $3
+      i32.add
+      local.get $4
+      local.get $3
+      i32.add
+      i32.load8_u
+      i32.store8
+      br $while-continue|5
+     end
+    end
+   end
+  end
+ )
+ (func $~lib/rt/tlsf/__free (; 29 ;) (param $0 i32)
+  local.get $0
+  i32.const 0
+  i32.ne
+  if (result i32)
+   local.get $0
+   i32.const 15
+   i32.and
+   i32.eqz
+  else
+   i32.const 0
+  end
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 32
+   i32.const 593
+   i32.const 2
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $~lib/rt/tlsf/maybeInitialize
+  local.get $0
+  i32.const 16
+  i32.sub
+  call $~lib/rt/tlsf/freeBlock
+ )
+ (func $~lib/rt/pure/growRoots (; 30 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  global.get $~lib/rt/pure/ROOTS
+  local.set $0
+  global.get $~lib/rt/pure/CUR
+  local.get $0
+  i32.sub
+  local.set $1
+  local.get $1
+  i32.const 2
+  i32.mul
+  local.tee $2
+  i32.const 64
+  i32.const 2
+  i32.shl
+  local.tee $3
+  local.get $2
+  local.get $3
+  i32.gt_u
+  select
+  local.set $4
+  local.get $4
+  i32.const 0
+  call $~lib/rt/tlsf/__alloc
+  local.set $5
+  local.get $5
+  i32.const 16
+  i32.sub
+  call $~lib/rt/rtrace/onfree
+  local.get $5
+  local.get $0
+  local.get $1
+  call $~lib/memory/memory.copy
+  local.get $0
+  if
+   local.get $0
+   i32.const 16
+   i32.sub
+   call $~lib/rt/rtrace/onalloc
+   local.get $0
+   call $~lib/rt/tlsf/__free
+  end
+  local.get $5
+  global.set $~lib/rt/pure/ROOTS
+  local.get $5
+  local.get $1
+  i32.add
+  global.set $~lib/rt/pure/CUR
+  local.get $5
+  local.get $4
+  i32.add
+  global.set $~lib/rt/pure/END
+ )
+ (func $~lib/rt/pure/appendRoot (; 31 ;) (param $0 i32)
+  (local $1 i32)
+  global.get $~lib/rt/pure/CUR
+  local.set $1
+  local.get $1
+  global.get $~lib/rt/pure/END
+  i32.ge_u
+  if
+   call $~lib/rt/pure/growRoots
+   global.get $~lib/rt/pure/CUR
+   local.set $1
+  end
+  local.get $1
+  local.get $0
+  i32.store
+  local.get $1
+  i32.const 4
+  i32.add
+  global.set $~lib/rt/pure/CUR
+ )
+ (func $~lib/rt/pure/decrement (; 32 ;) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  i32.load offset=4
+  local.set $1
+  local.get $1
+  i32.const 268435455
+  i32.and
+  local.set $2
+  local.get $0
+  call $~lib/rt/rtrace/ondecrement
+  local.get $0
+  i32.load
+  i32.const 1
+  i32.and
+  i32.eqz
+  i32.eqz
+  if
+   i32.const 0
+   i32.const 144
+   i32.const 115
+   i32.const 13
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.get $2
+  i32.const 1
+  i32.eq
+  if
+   local.get $0
+   i32.const 16
+   i32.add
+   i32.const 1
+   call $~lib/rt/__visit_members
+   local.get $1
+   i32.const -2147483648
+   i32.and
+   i32.eqz
+   if
+    global.get $~lib/rt/tlsf/ROOT
+    local.get $0
+    call $~lib/rt/tlsf/freeBlock
+   else
+    local.get $0
+    i32.const -2147483648
+    i32.const 0
+    i32.or
+    i32.const 0
+    i32.or
+    i32.store offset=4
+   end
+  else
+   local.get $2
+   i32.const 0
+   i32.gt_u
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 144
+    i32.const 124
+    i32.const 15
+    call $~lib/builtins/abort
+    unreachable
+   end
+   local.get $0
+   i32.load offset=8
+   call $~lib/rt/__typeinfo
+   i32.const 16
+   i32.and
+   i32.eqz
+   if
+    local.get $0
+    i32.const -2147483648
+    i32.const 805306368
+    i32.or
+    local.get $2
+    i32.const 1
+    i32.sub
+    i32.or
+    i32.store offset=4
+    local.get $1
+    i32.const -2147483648
+    i32.and
+    i32.eqz
+    if
+     local.get $0
+     call $~lib/rt/pure/appendRoot
+    end
+   else
+    local.get $0
+    local.get $1
+    i32.const 268435455
+    i32.const -1
+    i32.xor
+    i32.and
+    local.get $2
+    i32.const 1
+    i32.sub
+    i32.or
+    i32.store offset=4
+   end
+  end
+ )
+ (func $~lib/rt/pure/__release (; 33 ;) (param $0 i32)
+  local.get $0
+  global.get $~lib/heap/__heap_base
+  i32.gt_u
+  if
+   local.get $0
+   i32.const 16
+   i32.sub
+   call $~lib/rt/pure/decrement
+  end
+ )
+ (func $managed-cast/testDowncast (; 34 ;) (param $0 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  call $managed-cast/Animal#tame
+  local.get $0
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testDowncastFromNullable (; 35 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  local.tee $1
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 14
+   i32.const 11
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Animal#tame
+  local.get $0
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testDowncastToNullable (; 36 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $1
+  local.get $1
+  if
+   local.get $1
+   call $managed-cast/Animal#tame
+  end
+  local.get $0
+  call $~lib/rt/pure/__release
+  local.get $1
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testDowncastFromToNullable (; 37 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $1
+  local.get $1
+  if
+   local.get $1
+   call $managed-cast/Animal#tame
+  end
+  local.get $0
+  call $~lib/rt/pure/__release
+  local.get $1
+  call $~lib/rt/pure/__release
+ )
+ (func $~lib/rt/__instanceof (; 38 ;) (param $0 i32) (param $1 i32) (result i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  local.get $0
+  i32.const 16
+  i32.sub
+  i32.load offset=8
+  local.set $2
+  global.get $~lib/rt/__rtti_base
+  local.set $3
+  local.get $2
+  local.get $3
+  i32.load
+  i32.le_u
+  if
+   loop $do-continue|0
+    local.get $2
+    local.get $1
+    i32.eq
+    if
+     i32.const 1
+     return
+    end
+    local.get $3
+    i32.const 4
+    i32.add
+    local.get $2
+    i32.const 8
+    i32.mul
+    i32.add
+    i32.load offset=4
+    local.tee $2
+    local.set $4
+    local.get $4
+    br_if $do-continue|0
+   end
+  end
+  i32.const 0
+ )
+ (func $managed-cast/Cat#meow (; 39 ;) (param $0 i32)
+  nop
+ )
+ (func $managed-cast/testUpcast (; 40 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  local.tee $1
+  i32.const 3
+  call $~lib/rt/__instanceof
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 31
+   i32.const 8
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Cat#meow
+  local.get $0
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testUpcastFromNullable (; 41 ;) (param $0 i32)
+  (local $1 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  local.tee $1
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 36
+   i32.const 8
+   call $~lib/builtins/abort
+   unreachable
+  end
+  local.tee $1
+  i32.const 3
+  call $~lib/rt/__instanceof
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 36
+   i32.const 8
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $managed-cast/Cat#meow
+  local.get $0
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testUpcastToNullable (; 42 ;) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  local.tee $1
+  i32.const 3
+  call $~lib/rt/__instanceof
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 41
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $~lib/rt/pure/__retain
+  local.set $2
+  local.get $2
+  if
+   local.get $2
+   call $managed-cast/Cat#meow
+  end
+  local.get $0
+  call $~lib/rt/pure/__release
+  local.get $2
+  call $~lib/rt/pure/__release
+ )
+ (func $managed-cast/testUpcastFromToNullable (; 43 ;) (param $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  local.get $0
+  call $~lib/rt/pure/__retain
+  local.set $0
+  local.get $0
+  local.tee $1
+  i32.const 3
+  call $~lib/rt/__instanceof
+  if (result i32)
+   local.get $1
+  else
+   i32.const 0
+   i32.const 304
+   i32.const 47
+   i32.const 29
+   call $~lib/builtins/abort
+   unreachable
+  end
+  call $~lib/rt/pure/__retain
+  local.set $2
+  local.get $2
+  if
+   local.get $2
+   call $managed-cast/Cat#meow
+  end
+  local.get $0
+  call $~lib/rt/pure/__release
+  local.get $2
+  call $~lib/rt/pure/__release
+ )
+ (func $start:managed-cast (; 44 ;)
+  (local $0 i32)
+  (local $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  (local $4 i32)
+  (local $5 i32)
+  (local $6 i32)
+  (local $7 i32)
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $0
+  call $managed-cast/testDowncast
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $1
+  call $managed-cast/testDowncastFromNullable
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $2
+  call $managed-cast/testDowncastToNullable
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $3
+  call $managed-cast/testDowncastFromToNullable
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $4
+  call $managed-cast/testUpcast
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $5
+  call $managed-cast/testUpcastFromNullable
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $6
+  call $managed-cast/testUpcastToNullable
+  i32.const 0
+  call $managed-cast/Cat#constructor
+  local.tee $7
+  call $managed-cast/testUpcastFromToNullable
+  local.get $0
+  call $~lib/rt/pure/__release
+  local.get $1
+  call $~lib/rt/pure/__release
+  local.get $2
+  call $~lib/rt/pure/__release
+  local.get $3
+  call $~lib/rt/pure/__release
+  local.get $4
+  call $~lib/rt/pure/__release
+  local.get $5
+  call $~lib/rt/pure/__release
+  local.get $6
+  call $~lib/rt/pure/__release
+  local.get $7
+  call $~lib/rt/pure/__release
+ )
+ (func $~start (; 45 ;)
+  global.get $~started
+  if
+   return
+  else
+   i32.const 1
+   global.set $~started
+  end
+  call $start:managed-cast
+ )
+ (func $~lib/rt/pure/__visit (; 46 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  (local $3 i32)
+  local.get $0
+  global.get $~lib/heap/__heap_base
+  i32.lt_u
+  if
+   return
+  end
+  local.get $0
+  i32.const 16
+  i32.sub
+  local.set $2
+  block $break|0
+   block $case5|0
+    block $case4|0
+     block $case3|0
+      block $case2|0
+       block $case1|0
+        block $case0|0
+         local.get $1
+         local.set $3
+         local.get $3
+         i32.const 1
+         i32.eq
+         br_if $case0|0
+         local.get $3
+         i32.const 2
+         i32.eq
+         br_if $case1|0
+         local.get $3
+         i32.const 3
+         i32.eq
+         br_if $case2|0
+         local.get $3
+         i32.const 4
+         i32.eq
+         br_if $case3|0
+         local.get $3
+         i32.const 5
+         i32.eq
+         br_if $case4|0
+         br $case5|0
+        end
+        local.get $2
+        call $~lib/rt/pure/decrement
+        br $break|0
+       end
+       local.get $2
+       i32.load offset=4
+       i32.const 268435455
+       i32.and
+       i32.const 0
+       i32.gt_u
+       i32.eqz
+       if
+        i32.const 0
+        i32.const 144
+        i32.const 75
+        i32.const 17
+        call $~lib/builtins/abort
+        unreachable
+       end
+       local.get $2
+       local.get $2
+       i32.load offset=4
+       i32.const 1
+       i32.sub
+       i32.store offset=4
+       local.get $2
+       call $~lib/rt/pure/markGray
+       br $break|0
+      end
+      local.get $2
+      call $~lib/rt/pure/scan
+      br $break|0
+     end
+     local.get $2
+     i32.load offset=4
+     local.set $3
+     local.get $3
+     i32.const -268435456
+     i32.and
+     local.get $3
+     i32.const 1
+     i32.add
+     i32.const -268435456
+     i32.and
+     i32.eq
+     i32.eqz
+     if
+      i32.const 0
+      i32.const 144
+      i32.const 86
+      i32.const 6
+      call $~lib/builtins/abort
+      unreachable
+     end
+     local.get $2
+     local.get $3
+     i32.const 1
+     i32.add
+     i32.store offset=4
+     local.get $3
+     i32.const 1879048192
+     i32.and
+     i32.const 0
+     i32.ne
+     if
+      local.get $2
+      call $~lib/rt/pure/scanBlack
+     end
+     br $break|0
+    end
+    local.get $2
+    call $~lib/rt/pure/collectWhite
+    br $break|0
+   end
+   i32.const 0
+   i32.eqz
+   if
+    i32.const 0
+    i32.const 144
+    i32.const 97
+    i32.const 24
+    call $~lib/builtins/abort
+    unreachable
+   end
+  end
+ )
+ (func $~lib/rt/__visit_members (; 47 ;) (param $0 i32) (param $1 i32)
+  (local $2 i32)
+  block $switch$1$default
+   block $switch$1$case$4
+    block $switch$1$case$2
+     local.get $0
+     i32.const 8
+     i32.sub
+     i32.load
+     br_table $switch$1$case$2 $switch$1$case$2 $switch$1$case$4 $switch$1$case$2 $switch$1$case$2 $switch$1$default
+    end
+    return
+   end
+   local.get $0
+   i32.load
+   local.tee $2
+   if
+    local.get $2
+    local.get $1
+    call $~lib/rt/pure/__visit
+   end
+   return
+  end
+  unreachable
+ )
+)
diff --git a/tests/compiler/nullable.json b/tests/compiler/nullable.json
index 7454efd143..ae5a982120 100644
--- a/tests/compiler/nullable.json
+++ b/tests/compiler/nullable.json
@@ -3,7 +3,7 @@
     "--runtime none"
   ],
   "stderr": [
-    "TS2531: Object is possibly 'null'.",
+    "TS2322: Type 'nullable/Example | null' is not assignable to type 'nullable/Example'.",
     "EOF"
   ]
 }
\ No newline at end of file
diff --git a/tests/compiler/std/array.optimized.wat b/tests/compiler/std/array.optimized.wat
index 35faf25e73..5006934d88 100644
--- a/tests/compiler/std/array.optimized.wat
+++ b/tests/compiler/std/array.optimized.wat
@@ -13930,6 +13930,11 @@
   local.get $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 416
+   i32.const 434
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
@@ -13974,6 +13979,11 @@
   local.get $3
   i32.eqz
   if
+   i32.const 0
+   i32.const 416
+   i32.const 438
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
diff --git a/tests/compiler/std/array.untouched.wat b/tests/compiler/std/array.untouched.wat
index 615b652d86..cbcf719961 100644
--- a/tests/compiler/std/array.untouched.wat
+++ b/tests/compiler/std/array.untouched.wat
@@ -21744,6 +21744,11 @@
   if (result i32)
    local.get $55
   else
+   i32.const 0
+   i32.const 416
+   i32.const 434
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
@@ -21794,6 +21799,11 @@
   if (result i32)
    local.get $62
   else
+   i32.const 0
+   i32.const 416
+   i32.const 438
+   i32.const 9
+   call $~lib/builtins/abort
    unreachable
   end
   i32.load
diff --git a/tests/compiler/std/symbol.optimized.wat b/tests/compiler/std/symbol.optimized.wat
index b035120cc0..5f401ce42c 100644
--- a/tests/compiler/std/symbol.optimized.wat
+++ b/tests/compiler/std/symbol.optimized.wat
@@ -1610,6 +1610,11 @@
   local.tee $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 64
+   i32.const 17
+   i32.const 11
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
@@ -1619,6 +1624,11 @@
   local.tee $0
   i32.eqz
   if
+   i32.const 0
+   i32.const 64
+   i32.const 18
+   i32.const 11
+   call $~lib/builtins/abort
    unreachable
   end
   local.get $0
diff --git a/tests/compiler/std/symbol.untouched.wat b/tests/compiler/std/symbol.untouched.wat
index 2b8f16b117..51d30d5d49 100644
--- a/tests/compiler/std/symbol.untouched.wat
+++ b/tests/compiler/std/symbol.untouched.wat
@@ -3405,6 +3405,11 @@
   if (result i32)
    local.get $0
   else
+   i32.const 0
+   i32.const 64
+   i32.const 17
+   i32.const 11
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain
@@ -3415,6 +3420,11 @@
   if (result i32)
    local.get $0
   else
+   i32.const 0
+   i32.const 64
+   i32.const 18
+   i32.const 11
+   call $~lib/builtins/abort
    unreachable
   end
   call $~lib/rt/stub/__retain