diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 2557e3b707827..d470a9d778509 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -118,6 +118,7 @@ namespace ts {
         let thisParentContainer: Node; // Container one level up
         let blockScopeContainer: Node;
         let lastContainer: Node;
+        let delayedTypedefs: { typedef: JSDocTypedefTag, container: Node, lastContainer: Node, blockScopeContainer: Node, parent: Node }[];
         let seenThisKeyword: boolean;
 
         // state used by control flow analysis
@@ -176,6 +177,7 @@ namespace ts {
                 bind(file);
                 file.symbolCount = symbolCount;
                 file.classifiableNames = classifiableNames;
+                delayedBindJSDocTypedefTag();
             }
 
             file = undefined;
@@ -186,6 +188,7 @@ namespace ts {
             thisParentContainer = undefined;
             blockScopeContainer = undefined;
             lastContainer = undefined;
+            delayedTypedefs = undefined;
             seenThisKeyword = false;
             currentFlow = undefined;
             currentBreakTarget = undefined;
@@ -450,8 +453,7 @@ namespace ts {
                 //       and this case is specially handled. Module augmentations should only be merged with original module definition
                 //       and should never be merged directly with other augmentation, and the latter case would be possible if automatic merge is allowed.
                 if (node.kind === SyntaxKind.JSDocTypedefTag) Debug.assert(isInJavaScriptFile(node)); // We shouldn't add symbols for JSDoc nodes if not in a JS file.
-                const isJSDocTypedefInJSDocNamespace = isJSDocTypedefTag(node) && node.name && node.name.kind === SyntaxKind.Identifier && node.name.isInJSDocNamespace;
-                if ((!isAmbientModule(node) && (hasExportModifier || container.flags & NodeFlags.ExportContext)) || isJSDocTypedefInJSDocNamespace) {
+                if ((!isAmbientModule(node) && (hasExportModifier || container.flags & NodeFlags.ExportContext)) || isJSDocTypedefTag(node)) {
                     if (hasModifier(node, ModifierFlags.Default) && !getDeclarationName(node)) {
                         return declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes); // No local symbol for an unnamed default!
                     }
@@ -1727,7 +1729,7 @@ namespace ts {
                     declareModuleMember(node, symbolFlags, symbolExcludes);
                     break;
                 case SyntaxKind.SourceFile:
-                    if (isExternalModule(<SourceFile>container)) {
+                    if (isExternalOrCommonJsModule(<SourceFile>container)) {
                         declareModuleMember(node, symbolFlags, symbolExcludes);
                         break;
                     }
@@ -1745,6 +1747,24 @@ namespace ts {
             bindBlockScopedDeclaration(node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
         }
 
+        function delayedBindJSDocTypedefTag() {
+            if (!delayedTypedefs) {
+                return;
+            }
+            const saveContainer = container;
+            const saveLastContainer = lastContainer;
+            const saveBlockScopeContainer = blockScopeContainer;
+            const saveParent = parent;
+            for (const delay of delayedTypedefs) {
+                ({ container, lastContainer, blockScopeContainer, parent } = delay);
+                bindBlockScopedDeclaration(delay.typedef, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
+            }
+            container = saveContainer;
+            lastContainer = saveLastContainer;
+            blockScopeContainer = saveBlockScopeContainer;
+            parent = saveParent;
+        }
+
         // The binder visits every node in the syntax tree so it is a convenient place to perform a single localized
         // check for reserved words used as identifiers in strict mode code.
         function checkStrictModeIdentifier(node: Identifier) {
@@ -2194,7 +2214,7 @@ namespace ts {
                 case SyntaxKind.JSDocTypedefTag: {
                     const { fullName } = node as JSDocTypedefTag;
                     if (!fullName || fullName.kind === SyntaxKind.Identifier) {
-                        return bindBlockScopedDeclaration(<Declaration>node, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
+                        (delayedTypedefs || (delayedTypedefs = [])).push({ typedef: node as JSDocTypedefTag, container, lastContainer, blockScopeContainer, parent });
                     }
                     break;
                 }
@@ -2304,7 +2324,10 @@ namespace ts {
                 return s;
             });
             if (symbol) {
-                declareSymbol(symbol.exports, symbol, lhs, SymbolFlags.Property | SymbolFlags.ExportValue, SymbolFlags.None);
+                const flags = isClassExpression(node.right) ?
+                    SymbolFlags.Property | SymbolFlags.ExportValue | SymbolFlags.Class :
+                    SymbolFlags.Property | SymbolFlags.ExportValue;
+                declareSymbol(symbol.exports, symbol, lhs, flags, SymbolFlags.None);
             }
         }
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 4886fc98e9a56..3bee345538d42 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -7626,23 +7626,38 @@ namespace ts {
                 return unknownType;
             }
 
-            // A jsdoc TypeReference may have resolved to a value (as opposed to a type). If
-            // the symbol is a constructor function, return the inferred class type; otherwise,
-            // the type of this reference is just the type of the value we resolved to.
+            const jsdocType = getJSDocTypeReference(node, symbol, typeArguments);
+            if (jsdocType) {
+                return jsdocType;
+            }
+
+            // Resolve the type reference as a Type for the purpose of reporting errors.
+            resolveTypeReferenceName(getTypeReferenceName(node), SymbolFlags.Type);
+            return getTypeOfSymbol(symbol);
+        }
+
+        /**
+         * A jsdoc TypeReference may have resolved to a value (as opposed to a type). If
+         * the symbol is a constructor function, return the inferred class type; otherwise,
+         * the type of this reference is just the type of the value we resolved to.
+         */
+        function getJSDocTypeReference(node: NodeWithTypeArguments, symbol: Symbol, typeArguments: Type[]): Type | undefined {
             const assignedType = getAssignedClassType(symbol);
             const valueType = getTypeOfSymbol(symbol);
-            const referenceType = valueType.symbol && !isInferredClassType(valueType) && getTypeReferenceTypeWorker(node, valueType.symbol, typeArguments);
+            const referenceType = valueType.symbol && valueType.symbol !== symbol && !isInferredClassType(valueType) && getTypeReferenceTypeWorker(node, valueType.symbol, typeArguments);
             if (referenceType || assignedType) {
                 return referenceType && assignedType ? getIntersectionType([assignedType, referenceType]) : referenceType || assignedType;
             }
-
-            // Resolve the type reference as a Type for the purpose of reporting errors.
-            resolveTypeReferenceName(getTypeReferenceName(node), SymbolFlags.Type);
-            return valueType;
         }
 
         function getTypeReferenceTypeWorker(node: NodeWithTypeArguments, symbol: Symbol, typeArguments: Type[]): Type | undefined {
             if (symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
+                if (symbol.valueDeclaration && isBinaryExpression(symbol.valueDeclaration.parent)) {
+                    const jsdocType = getJSDocTypeReference(node, symbol, typeArguments);
+                    if (jsdocType) {
+                        return jsdocType;
+                    }
+                }
                 return getTypeFromClassOrInterfaceReference(node, symbol, typeArguments);
             }
 
@@ -20031,6 +20046,7 @@ namespace ts {
                         getUnionType([removeDefinitelyFalsyTypes(leftType), rightType], UnionReduction.Subtype) :
                         leftType;
                 case SyntaxKind.EqualsToken:
+                    checkSpecialAssignment(left, right);
                     checkAssignmentOperator(rightType);
                     return getRegularTypeOfObjectLiteral(rightType);
                 case SyntaxKind.CommaToken:
@@ -20040,6 +20056,24 @@ namespace ts {
                     return rightType;
             }
 
+            function checkSpecialAssignment(left: Node, right: Expression) {
+                const special = getSpecialPropertyAssignmentKind(left.parent as BinaryExpression);
+                if (special === SpecialPropertyAssignmentKind.ModuleExports) {
+                    const rightType = checkExpression(right, checkMode);
+                    for (const prop of getPropertiesOfObjectType(rightType)) {
+                        const propType = getTypeOfSymbol(prop);
+                        if (propType.symbol && propType.symbol.flags & SymbolFlags.Class) {
+                            const name = prop.escapedName;
+                            const symbol = resolveName(prop.valueDeclaration, name, SymbolFlags.Type, undefined, name, /*isUse*/ false);
+                            if (symbol) {
+                                grammarErrorOnNode(symbol.declarations[0], Diagnostics.Duplicate_identifier_0, unescapeLeadingUnderscores(name));
+                                return grammarErrorOnNode(prop.valueDeclaration, Diagnostics.Duplicate_identifier_0, unescapeLeadingUnderscores(name));
+                            }
+                        }
+                    }
+                }
+            }
+
             function isEvalNode(node: Expression) {
                 return node.kind === SyntaxKind.Identifier && (node as Identifier).escapedText === "eval";
             }
diff --git a/src/harness/harness.ts b/src/harness/harness.ts
index 9fe26ed51c3ba..c955c1acb59d2 100644
--- a/src/harness/harness.ts
+++ b/src/harness/harness.ts
@@ -217,7 +217,7 @@ namespace Utils {
             for (const childName in node) {
                 if (childName === "parent" || childName === "nextContainer" || childName === "modifiers" || childName === "externalModuleIndicator" ||
                     // for now ignore jsdoc comments
-                    childName === "jsDocComment" || childName === "checkJsDirective") {
+                    childName === "jsDocComment" || childName === "checkJsDirective" || childName === "commonJsModuleIndicator") {
                     continue;
                 }
                 const child = (<any>node)[childName];
diff --git a/tests/baselines/reference/jsdocTypedefNoCrash.symbols b/tests/baselines/reference/jsdocTypedefNoCrash.symbols
index 8724c9da8d171..51f5fdcc259fc 100644
--- a/tests/baselines/reference/jsdocTypedefNoCrash.symbols
+++ b/tests/baselines/reference/jsdocTypedefNoCrash.symbols
@@ -4,5 +4,5 @@
  * }}
  */
 export const foo = 5;
->foo : Symbol(foo, Decl(export.js, 4, 12))
+>foo : Symbol(foo, Decl(export.js, 4, 12), Decl(export.js, 1, 3))
 
diff --git a/tests/baselines/reference/typedefCrossModule.symbols b/tests/baselines/reference/typedefCrossModule.symbols
new file mode 100644
index 0000000000000..2ba91903ba3ad
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule.symbols
@@ -0,0 +1,70 @@
+=== tests/cases/conformance/jsdoc/commonjs.d.ts ===
+declare var module: { exports: any};
+>module : Symbol(module, Decl(commonjs.d.ts, 0, 11))
+>exports : Symbol(exports, Decl(commonjs.d.ts, 0, 21))
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+module.exports = C
+>module.exports : Symbol(exports, Decl(commonjs.d.ts, 0, 21))
+>module : Symbol(export=, Decl(mod1.js, 0, 0))
+>exports : Symbol(export=, Decl(mod1.js, 0, 0))
+>C : Symbol(C, Decl(mod1.js, 4, 18))
+
+function C() {
+>C : Symbol(C, Decl(mod1.js, 4, 18))
+
+    this.p = 1
+>p : Symbol(C.p, Decl(mod1.js, 5, 14))
+}
+
+=== tests/cases/conformance/jsdoc/mod2.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+export function C() {
+>C : Symbol(C, Decl(mod2.js, 0, 0))
+
+    this.p = 1
+>p : Symbol(C.p, Decl(mod2.js, 5, 21))
+}
+
+=== tests/cases/conformance/jsdoc/mod3.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+exports.C = function() {
+>exports.C : Symbol(C, Decl(mod3.js, 0, 0))
+>exports : Symbol(C, Decl(mod3.js, 0, 0))
+>C : Symbol(C, Decl(mod3.js, 0, 0))
+
+    this.p = 1
+>p : Symbol(C.p, Decl(mod3.js, 5, 24))
+}
+
+=== tests/cases/conformance/jsdoc/use.js ===
+/** @type {import('./mod1').Both} */
+var both1 = { type: 'a', x: 1 };
+>both1 : Symbol(both1, Decl(use.js, 1, 3))
+>type : Symbol(type, Decl(use.js, 1, 13))
+>x : Symbol(x, Decl(use.js, 1, 24))
+
+/** @type {import('./mod2').Both} */
+var both2 = both1;
+>both2 : Symbol(both2, Decl(use.js, 3, 3))
+>both1 : Symbol(both1, Decl(use.js, 1, 3))
+
+/** @type {import('./mod3').Both} */
+var both3 = both2;
+>both3 : Symbol(both3, Decl(use.js, 5, 3))
+>both2 : Symbol(both2, Decl(use.js, 3, 3))
+
+
+
diff --git a/tests/baselines/reference/typedefCrossModule.types b/tests/baselines/reference/typedefCrossModule.types
new file mode 100644
index 0000000000000..665fa4989918b
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule.types
@@ -0,0 +1,88 @@
+=== tests/cases/conformance/jsdoc/commonjs.d.ts ===
+declare var module: { exports: any};
+>module : { exports: any; }
+>exports : any
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+module.exports = C
+>module.exports = C : typeof C
+>module.exports : any
+>module : { exports: any; }
+>exports : any
+>C : typeof C
+
+function C() {
+>C : typeof C
+
+    this.p = 1
+>this.p = 1 : 1
+>this.p : any
+>this : any
+>p : any
+>1 : 1
+}
+
+=== tests/cases/conformance/jsdoc/mod2.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+export function C() {
+>C : typeof C
+
+    this.p = 1
+>this.p = 1 : 1
+>this.p : any
+>this : any
+>p : any
+>1 : 1
+}
+
+=== tests/cases/conformance/jsdoc/mod3.js ===
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+exports.C = function() {
+>exports.C = function() {    this.p = 1} : typeof C
+>exports.C : typeof C
+>exports : typeof import("tests/cases/conformance/jsdoc/mod3")
+>C : typeof C
+>function() {    this.p = 1} : typeof C
+
+    this.p = 1
+>this.p = 1 : 1
+>this.p : any
+>this : any
+>p : any
+>1 : 1
+}
+
+=== tests/cases/conformance/jsdoc/use.js ===
+/** @type {import('./mod1').Both} */
+var both1 = { type: 'a', x: 1 };
+>both1 : { type: "a"; x: 1; } | { type: "b"; y: 1; }
+>{ type: 'a', x: 1 } : { type: "a"; x: 1; }
+>type : "a"
+>'a' : "a"
+>x : 1
+>1 : 1
+
+/** @type {import('./mod2').Both} */
+var both2 = both1;
+>both2 : { type: "a"; x: 1; } | { type: "b"; y: 1; }
+>both1 : { type: "a"; x: 1; }
+
+/** @type {import('./mod3').Both} */
+var both3 = both2;
+>both3 : { type: "a"; x: 1; } | { type: "b"; y: 1; }
+>both2 : { type: "a"; x: 1; }
+
+
+
diff --git a/tests/baselines/reference/typedefCrossModule2.errors.txt b/tests/baselines/reference/typedefCrossModule2.errors.txt
new file mode 100644
index 0000000000000..04d28448e5795
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule2.errors.txt
@@ -0,0 +1,64 @@
+tests/cases/conformance/jsdoc/mod1.js(3,23): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/conformance/jsdoc/mod1.js(4,7): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/conformance/jsdoc/mod1.js(6,23): error TS2300: Duplicate identifier 'Bar'.
+tests/cases/conformance/jsdoc/mod1.js(7,9): error TS2300: Duplicate identifier 'Bar'.
+tests/cases/conformance/jsdoc/mod1.js(9,5): error TS2300: Duplicate identifier 'Baz'.
+tests/cases/conformance/jsdoc/mod1.js(10,1): error TS2304: Cannot find name 'module'.
+tests/cases/conformance/jsdoc/mod1.js(11,5): error TS2300: Duplicate identifier 'Baz'.
+tests/cases/conformance/jsdoc/mod1.js(23,1): error TS2304: Cannot find name 'module'.
+tests/cases/conformance/jsdoc/use.js(1,11): error TS2304: Cannot find name 'require'.
+
+
+==== tests/cases/conformance/jsdoc/use.js (1 errors) ====
+    var mod = require('./mod1.js');
+              ~~~~~~~
+!!! error TS2304: Cannot find name 'require'.
+    /** @type {import("./mod1.js").Baz} */
+    var b;
+    /** @type {mod.Baz} */
+    var bb;
+    var bbb = new mod.Baz();
+    
+==== tests/cases/conformance/jsdoc/mod1.js (8 errors) ====
+    // error
+    
+    /** @typedef {number} Foo */
+                          ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    class Foo { } // should error
+          ~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    
+    /** @typedef {number} Bar */
+                          ~~~
+!!! error TS2300: Duplicate identifier 'Bar'.
+    exports.Bar = class { }
+            ~~~
+!!! error TS2300: Duplicate identifier 'Bar'.
+    
+    /** @typedef {number} Baz */
+        ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Baz'.
+    module.exports = {
+    ~~~~~~
+!!! error TS2304: Cannot find name 'module'.
+        Baz: class { }
+        ~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Baz'.
+    }
+    
+    // ok
+    
+    /** @typedef {number} Qux */
+    var Qux = 2;
+    
+    /** @typedef {number} Quid */
+    exports.Quid = 2;
+    
+    /** @typedef {number} Quack */
+    module.exports = {
+    ~~~~~~
+!!! error TS2304: Cannot find name 'module'.
+        Quack: 2
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typedefCrossModule2.symbols b/tests/baselines/reference/typedefCrossModule2.symbols
new file mode 100644
index 0000000000000..01afe2b9bdb75
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule2.symbols
@@ -0,0 +1,60 @@
+=== tests/cases/conformance/jsdoc/use.js ===
+var mod = require('./mod1.js');
+>mod : Symbol(mod, Decl(use.js, 0, 3))
+>'./mod1.js' : Symbol("tests/cases/conformance/jsdoc/mod1", Decl(mod1.js, 0, 0))
+
+/** @type {import("./mod1.js").Baz} */
+var b;
+>b : Symbol(b, Decl(use.js, 2, 3))
+
+/** @type {mod.Baz} */
+var bb;
+>bb : Symbol(bb, Decl(use.js, 4, 3))
+
+var bbb = new mod.Baz();
+>bbb : Symbol(bbb, Decl(use.js, 5, 3))
+>mod : Symbol(mod, Decl(use.js, 0, 3))
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+// error
+
+/** @typedef {number} Foo */
+class Foo { } // should error
+>Foo : Symbol(Foo, Decl(mod1.js, 0, 0))
+
+/** @typedef {number} Bar */
+exports.Bar = class { }
+>exports.Bar : Symbol(Bar, Decl(mod1.js, 3, 13))
+>exports : Symbol(Bar, Decl(mod1.js, 3, 13))
+>Bar : Symbol(Bar, Decl(mod1.js, 3, 13))
+
+/** @typedef {number} Baz */
+module.exports = {
+>module : Symbol(export=, Decl(mod1.js, 6, 23), Decl(mod1.js, 19, 17))
+>exports : Symbol(export=, Decl(mod1.js, 6, 23), Decl(mod1.js, 19, 17))
+
+    Baz: class { }
+>Baz : Symbol(Baz, Decl(mod1.js, 9, 18))
+}
+
+// ok
+
+/** @typedef {number} Qux */
+var Qux = 2;
+>Qux : Symbol(Qux, Decl(mod1.js, 16, 3), Decl(mod1.js, 15, 4))
+
+/** @typedef {number} Quid */
+exports.Quid = 2;
+>exports.Quid : Symbol(Quid, Decl(mod1.js, 16, 12), Decl(mod1.js, 18, 4))
+>exports : Symbol(Quid, Decl(mod1.js, 16, 12), Decl(mod1.js, 18, 4))
+>Quid : Symbol(Quid, Decl(mod1.js, 16, 12), Decl(mod1.js, 18, 4))
+
+/** @typedef {number} Quack */
+module.exports = {
+>module : Symbol(export=, Decl(mod1.js, 6, 23), Decl(mod1.js, 19, 17))
+>exports : Symbol(export=, Decl(mod1.js, 6, 23), Decl(mod1.js, 19, 17))
+
+    Quack: 2
+>Quack : Symbol(Quack, Decl(mod1.js, 22, 18))
+}
+
diff --git a/tests/baselines/reference/typedefCrossModule2.types b/tests/baselines/reference/typedefCrossModule2.types
new file mode 100644
index 0000000000000..67e4b7a4e890e
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule2.types
@@ -0,0 +1,78 @@
+=== tests/cases/conformance/jsdoc/use.js ===
+var mod = require('./mod1.js');
+>mod : { [x: string]: any; Baz: any; Bar: typeof Bar; Quid: any; } | { [x: string]: any; Quack: any; Bar: typeof Bar; Quid: any; }
+>require('./mod1.js') : { [x: string]: any; Baz: any; Bar: typeof Bar; Quid: any; } | { [x: string]: any; Quack: any; Bar: typeof Bar; Quid: any; }
+>require : any
+>'./mod1.js' : "./mod1.js"
+
+/** @type {import("./mod1.js").Baz} */
+var b;
+>b : number
+
+/** @type {mod.Baz} */
+var bb;
+>bb : number
+
+var bbb = new mod.Baz();
+>bbb : any
+>new mod.Baz() : any
+>mod.Baz : any
+>mod : { [x: string]: any; Baz: any; Bar: typeof Bar; Quid: any; } | { [x: string]: any; Quack: any; Bar: typeof Bar; Quid: any; }
+>Baz : any
+
+=== tests/cases/conformance/jsdoc/mod1.js ===
+// error
+
+/** @typedef {number} Foo */
+class Foo { } // should error
+>Foo : Foo
+
+/** @typedef {number} Bar */
+exports.Bar = class { }
+>exports.Bar = class { } : typeof Bar
+>exports.Bar : typeof Bar
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>Bar : typeof Bar
+>class { } : typeof Bar
+
+/** @typedef {number} Baz */
+module.exports = {
+>module.exports = {    Baz: class { }} : { [x: string]: any; Baz: typeof Baz; }
+>module.exports : any
+>module : any
+>exports : any
+>{    Baz: class { }} : { [x: string]: any; Baz: typeof Baz; }
+
+    Baz: class { }
+>Baz : typeof Baz
+>class { } : typeof Baz
+}
+
+// ok
+
+/** @typedef {number} Qux */
+var Qux = 2;
+>Qux : number
+>2 : 2
+
+/** @typedef {number} Quid */
+exports.Quid = 2;
+>exports.Quid = 2 : 2
+>exports.Quid : any
+>exports : typeof import("tests/cases/conformance/jsdoc/mod1")
+>Quid : any
+>2 : 2
+
+/** @typedef {number} Quack */
+module.exports = {
+>module.exports = {    Quack: 2} : { [x: string]: any; Quack: number; }
+>module.exports : any
+>module : any
+>exports : any
+>{    Quack: 2} : { [x: string]: any; Quack: number; }
+
+    Quack: 2
+>Quack : number
+>2 : 2
+}
+
diff --git a/tests/baselines/reference/typedefCrossModule3.errors.txt b/tests/baselines/reference/typedefCrossModule3.errors.txt
new file mode 100644
index 0000000000000..5309528fb4e6c
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule3.errors.txt
@@ -0,0 +1,18 @@
+tests/cases/conformance/jsdoc/mod2.js(1,5): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/conformance/jsdoc/mod2.js(3,1): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/conformance/jsdoc/mod2.js(4,1): error TS2304: Cannot find name 'module'.
+
+
+==== tests/cases/conformance/jsdoc/mod2.js (3 errors) ====
+    /** @typedef {number} Foo */
+        ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    const ns = {};
+    ns.Foo = class {}
+    ~~~~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    module.exports = ns;
+    ~~~~~~
+!!! error TS2304: Cannot find name 'module'.
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typedefCrossModule3.symbols b/tests/baselines/reference/typedefCrossModule3.symbols
new file mode 100644
index 0000000000000..3e1c8a55535df
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule3.symbols
@@ -0,0 +1,16 @@
+=== tests/cases/conformance/jsdoc/mod2.js ===
+/** @typedef {number} Foo */
+const ns = {};
+>ns : Symbol(ns, Decl(mod2.js, 1, 5), Decl(mod2.js, 1, 14))
+
+ns.Foo = class {}
+>ns.Foo : Symbol(Foo, Decl(mod2.js, 1, 14))
+>ns : Symbol(ns, Decl(mod2.js, 1, 5), Decl(mod2.js, 1, 14))
+>Foo : Symbol(Foo, Decl(mod2.js, 1, 14))
+
+module.exports = ns;
+>module : Symbol(export=, Decl(mod2.js, 2, 17))
+>exports : Symbol(export=, Decl(mod2.js, 2, 17))
+>ns : Symbol(ns, Decl(mod2.js, 1, 5), Decl(mod2.js, 1, 14))
+
+
diff --git a/tests/baselines/reference/typedefCrossModule3.types b/tests/baselines/reference/typedefCrossModule3.types
new file mode 100644
index 0000000000000..9d3767dcbbaba
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule3.types
@@ -0,0 +1,21 @@
+=== tests/cases/conformance/jsdoc/mod2.js ===
+/** @typedef {number} Foo */
+const ns = {};
+>ns : { [x: string]: any; Foo: typeof Foo; }
+>{} : { [x: string]: any; Foo: typeof Foo; }
+
+ns.Foo = class {}
+>ns.Foo = class {} : typeof Foo
+>ns.Foo : typeof Foo
+>ns : { [x: string]: any; Foo: typeof Foo; }
+>Foo : typeof Foo
+>class {} : typeof Foo
+
+module.exports = ns;
+>module.exports = ns : { [x: string]: any; Foo: typeof Foo; }
+>module.exports : any
+>module : any
+>exports : any
+>ns : { [x: string]: any; Foo: typeof Foo; }
+
+
diff --git a/tests/baselines/reference/typedefCrossModule4.errors.txt b/tests/baselines/reference/typedefCrossModule4.errors.txt
new file mode 100644
index 0000000000000..5dcd9ac017bfe
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule4.errors.txt
@@ -0,0 +1,17 @@
+tests/cases/conformance/jsdoc/mod3.js(1,5): error TS2300: Duplicate identifier 'Foo'.
+tests/cases/conformance/jsdoc/mod3.js(3,1): error TS2304: Cannot find name 'module'.
+tests/cases/conformance/jsdoc/mod3.js(3,20): error TS2300: Duplicate identifier 'Foo'.
+
+
+==== tests/cases/conformance/jsdoc/mod3.js (3 errors) ====
+    /** @typedef {number} Foo */
+        ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    class Bar { }
+    module.exports = { Foo: Bar };
+    ~~~~~~
+!!! error TS2304: Cannot find name 'module'.
+                       ~~~~~~~~
+!!! error TS2300: Duplicate identifier 'Foo'.
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typedefCrossModule4.symbols b/tests/baselines/reference/typedefCrossModule4.symbols
new file mode 100644
index 0000000000000..aa478df301a9c
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule4.symbols
@@ -0,0 +1,12 @@
+=== tests/cases/conformance/jsdoc/mod3.js ===
+/** @typedef {number} Foo */
+class Bar { }
+>Bar : Symbol(Bar, Decl(mod3.js, 0, 0))
+
+module.exports = { Foo: Bar };
+>module : Symbol(export=, Decl(mod3.js, 1, 13))
+>exports : Symbol(export=, Decl(mod3.js, 1, 13))
+>Foo : Symbol(Foo, Decl(mod3.js, 2, 18))
+>Bar : Symbol(Bar, Decl(mod3.js, 0, 0))
+
+
diff --git a/tests/baselines/reference/typedefCrossModule4.types b/tests/baselines/reference/typedefCrossModule4.types
new file mode 100644
index 0000000000000..a0d14942ef3b5
--- /dev/null
+++ b/tests/baselines/reference/typedefCrossModule4.types
@@ -0,0 +1,15 @@
+=== tests/cases/conformance/jsdoc/mod3.js ===
+/** @typedef {number} Foo */
+class Bar { }
+>Bar : Bar
+
+module.exports = { Foo: Bar };
+>module.exports = { Foo: Bar } : { [x: string]: any; Foo: typeof Bar; }
+>module.exports : any
+>module : any
+>exports : any
+>{ Foo: Bar } : { [x: string]: any; Foo: typeof Bar; }
+>Foo : typeof Bar
+>Bar : typeof Bar
+
+
diff --git a/tests/cases/conformance/jsdoc/typedefCrossModule.ts b/tests/cases/conformance/jsdoc/typedefCrossModule.ts
new file mode 100644
index 0000000000000..772a41da7bf82
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/typedefCrossModule.ts
@@ -0,0 +1,44 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @Filename: commonjs.d.ts
+declare var module: { exports: any};
+// @Filename: mod1.js
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+module.exports = C
+function C() {
+    this.p = 1
+}
+
+// @Filename: mod2.js
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+export function C() {
+    this.p = 1
+}
+
+// @Filename: mod3.js
+/// <reference path="./commonjs.d.ts"/>
+/** @typedef {{ type: "a", x: 1 }} A */
+/** @typedef {{ type: "b", y: 1 }} B */
+/** @typedef {A | B} Both */
+
+exports.C = function() {
+    this.p = 1
+}
+
+// @Filename: use.js
+/** @type {import('./mod1').Both} */
+var both1 = { type: 'a', x: 1 };
+/** @type {import('./mod2').Both} */
+var both2 = both1;
+/** @type {import('./mod3').Both} */
+var both3 = both2;
+
+
diff --git a/tests/cases/conformance/jsdoc/typedefCrossModule2.ts b/tests/cases/conformance/jsdoc/typedefCrossModule2.ts
new file mode 100644
index 0000000000000..6bb00957ef396
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/typedefCrossModule2.ts
@@ -0,0 +1,39 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @Filename: mod1.js
+
+// error
+
+/** @typedef {number} Foo */
+class Foo { } // should error
+
+/** @typedef {number} Bar */
+exports.Bar = class { }
+
+/** @typedef {number} Baz */
+module.exports = {
+    Baz: class { }
+}
+
+// ok
+
+/** @typedef {number} Qux */
+var Qux = 2;
+
+/** @typedef {number} Quid */
+exports.Quid = 2;
+
+/** @typedef {number} Quack */
+module.exports = {
+    Quack: 2
+}
+
+// @Filename: use.js
+
+var mod = require('./mod1.js');
+/** @type {import("./mod1.js").Baz} */
+var b;
+/** @type {mod.Baz} */
+var bb;
+var bbb = new mod.Baz();
diff --git a/tests/cases/conformance/jsdoc/typedefCrossModule3.ts b/tests/cases/conformance/jsdoc/typedefCrossModule3.ts
new file mode 100644
index 0000000000000..d6005b541dcb7
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/typedefCrossModule3.ts
@@ -0,0 +1,10 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @Filename: mod2.js
+
+/** @typedef {number} Foo */
+const ns = {};
+ns.Foo = class {}
+module.exports = ns;
+
diff --git a/tests/cases/conformance/jsdoc/typedefCrossModule4.ts b/tests/cases/conformance/jsdoc/typedefCrossModule4.ts
new file mode 100644
index 0000000000000..09d27246c7c8f
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/typedefCrossModule4.ts
@@ -0,0 +1,9 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @Filename: mod3.js
+
+/** @typedef {number} Foo */
+class Bar { }
+module.exports = { Foo: Bar };
+
diff --git a/tests/cases/fourslash/findAllRefsClassExpression2.ts b/tests/cases/fourslash/findAllRefsClassExpression2.ts
index f25e64a2c68e8..1214e3f7c8856 100644
--- a/tests/cases/fourslash/findAllRefsClassExpression2.ts
+++ b/tests/cases/fourslash/findAllRefsClassExpression2.ts
@@ -10,7 +10,7 @@
 ////[|A|];
 
 const [r0, r1, r2] = test.ranges();
-const defs = { definition: "(property) A: typeof A", ranges: [r0] };
-const imports = { definition: "(alias) (property) A: typeof A\nimport A", ranges: [r1, r2] };
+const defs = { definition: "class A\n(property) A: typeof A", ranges: [r0] };
+const imports = { definition: "(alias) class A\n(alias) (property) A: typeof A\nimport A", ranges: [r1, r2] };
 verify.referenceGroups([r0], [defs, imports]);
 verify.referenceGroups([r1, r2], [imports, defs]);
diff --git a/tests/cases/fourslash/refactorConvertToEs6Module_export_named.ts b/tests/cases/fourslash/refactorConvertToEs6Module_export_named.ts
index e7ee290858038..f8eba2b02134b 100644
--- a/tests/cases/fourslash/refactorConvertToEs6Module_export_named.ts
+++ b/tests/cases/fourslash/refactorConvertToEs6Module_export_named.ts
@@ -21,7 +21,9 @@ verify.codeFix({
     description: "Convert to ES6 module",
     newFileContent:
 `export function f() {}
-export class C {}
+const _C = class {
+};
+export { _C as C };
 export const x = 0;
 export function a1() {}
 export function a2() { return 0; }
diff --git a/tests/cases/fourslash/refactorConvertToEs6Module_export_namedClassExpression.ts b/tests/cases/fourslash/refactorConvertToEs6Module_export_namedClassExpression.ts
index e1cb86e8d682e..47b8a5e0b32cf 100644
--- a/tests/cases/fourslash/refactorConvertToEs6Module_export_namedClassExpression.ts
+++ b/tests/cases/fourslash/refactorConvertToEs6Module_export_namedClassExpression.ts
@@ -10,6 +10,12 @@
 verify.codeFix({
     description: "Convert to ES6 module",
     newFileContent:
-`export const C = class E { static instance = new E(); }
-export class D { static instance = new D(); }`,
+`const _C = class E {
+    static instance = new E();
+};
+export { _C as C };
+const _D = class D {
+    static instance = new D();
+};
+export { _D as D };`,
 });
diff --git a/tests/cases/fourslash/refactorConvertToEs6Module_expressionToDeclaration.ts b/tests/cases/fourslash/refactorConvertToEs6Module_expressionToDeclaration.ts
index 47ff26f459ed2..b360334767f9e 100644
--- a/tests/cases/fourslash/refactorConvertToEs6Module_expressionToDeclaration.ts
+++ b/tests/cases/fourslash/refactorConvertToEs6Module_expressionToDeclaration.ts
@@ -11,5 +11,8 @@ verify.codeFix({
     description: "Convert to ES6 module",
     newFileContent:
 `export async function* f(p) { p; }
-export class C extends D { m() {} }`,
+const _C = class C extends D {
+    m() { }
+};
+export { _C as C };`,
 });