Flow analysis: implement "why not promoted" logic for boolean conditions

Bug: #44898
Change-Id: Ia8f3a5ad2971dfb6baeefb0d2f9c6998af0d897e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/192611
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: stereotype441

pkg/_fe_analyzer_shared/test/flow_analysis/why_not_promoted/data/argument_type_not_assignable_nullability_error.dart

@@ -164,3 +164,129 @@ orOperand(C12 c, bool b) {
       /*analyzer.notPromoted(propertyNotPromoted(target: member:C12.bad, type: bool?))*/ c
           . /*cfe.notPromoted(propertyNotPromoted(target: member:C12.bad, type: bool?))*/ bad);
 }
+
+class C13 {
+  bool? bad;
+}
+
+assertStatementCondition(C13 c) {
+  if (c.bad == null) return;
+  assert(
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C13.bad, type: bool?))*/ c
+          . /*cfe.notPromoted(propertyNotPromoted(target: member:C13.bad, type: bool?))*/ bad);
+}
+
+class C14 {
+  bool? bad;
+  C14.assertInitializerCondition(C14 c)
+      : bad = c.bad!,
+        assert(
+            /*analyzer.notPromoted(propertyNotPromoted(target: member:C14.bad, type: bool?))*/ c
+                . /*cfe.notPromoted(propertyNotPromoted(target: member:C14.bad, type: bool?))*/ bad);
+}
+
+class C15 {
+  bool? bad;
+  f(bool b) {}
+}
+
+notOperand(C15 c) {
+  if (c.bad == null) return;
+  c.f(!
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C15.bad, type: bool?))*/ c
+          . /*cfe.notPromoted(propertyNotPromoted(target: member:C15.bad, type: bool?))*/ bad);
+}
+
+class C16 {
+  bool? bad;
+  f(bool b) {}
+}
+
+forLoopCondition(C16 c) {
+  if (c.bad == null) return;
+  for (;
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ c
+          . /*cfe.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ bad;) {}
+  [
+    for (;
+        /*analyzer.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ c
+            . /*cfe.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ bad;)
+      null
+  ];
+  ({
+    for (;
+        /*analyzer.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ c
+            . /*cfe.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ bad;)
+      null
+  });
+  ({
+    for (;
+        /*analyzer.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ c
+            . /*cfe.notPromoted(propertyNotPromoted(target: member:C16.bad, type: bool?))*/ bad;)
+      null: null
+  });
+}
+
+class C17 {
+  bool? bad;
+  f(int i) {}
+}
+
+conditionalExpressionCondition(C17 c) {
+  if (c.bad == null) return;
+  c.f(
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C17.bad, type: bool?))*/ c
+              . /*cfe.notPromoted(propertyNotPromoted(target: member:C17.bad, type: bool?))*/ bad
+          ? 1
+          : 2);
+}
+
+class C18 {
+  bool? bad;
+}
+
+doLoopCondition(C18 c) {
+  if (c.bad == null) return;
+  do {} while (
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C18.bad, type: bool?))*/ c
+          . /*cfe.notPromoted(propertyNotPromoted(target: member:C18.bad, type: bool?))*/ bad);
+}
+
+class C19 {
+  bool? bad;
+}
+
+ifCondition(C19 c) {
+  if (c.bad == null) return;
+  if (
+      /*analyzer.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ c
+          . /*cfe.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ bad) {}
+  [
+    if (
+    /*analyzer.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ c
+        . /*cfe.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ bad)
+      null
+  ];
+  ({
+    if (
+    /*analyzer.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ c
+        . /*cfe.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ bad)
+      null
+  });
+  ({
+    if (
+    /*analyzer.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ c
+        . /*cfe.notPromoted(propertyNotPromoted(target: member:C19.bad, type: bool?))*/ bad)
+      null: null
+  });
+}
+
+class C20 {
+  bool? bad;
+}
+
+whileCondition(C20 c) {
+  if (c.bad == null) return;
+  while (/*analyzer.notPromoted(propertyNotPromoted(target: member:C20.bad, type: bool?))*/ c
+      . /*cfe.notPromoted(propertyNotPromoted(target: member:C20.bad, type: bool?))*/ bad) {}
+}

pkg/analyzer/lib/src/dart/resolver/for_resolver.dart

@@ -159,7 +159,10 @@ class ForResolver {
       InferenceContext.setType(condition, _resolver.typeProvider.boolType);
       condition.accept(_resolver);
       condition = forParts.condition!;
-      _resolver.boolExpressionVerifier.checkForNonBoolCondition(condition);
+      var whyNotPromoted =
+          _resolver.flowAnalysis?.flow?.whyNotPromoted(condition);
+      _resolver.boolExpressionVerifier
+          .checkForNonBoolCondition(condition, whyNotPromoted: whyNotPromoted);
     }
 
     _resolver.flowAnalysis?.for_bodyBegin(node, condition);

pkg/analyzer/lib/src/dart/resolver/prefix_expression_resolver.dart

@@ -226,8 +226,10 @@ class PrefixExpressionResolver {
 
     operand.accept(_resolver);
     operand = node.operand;
+    var whyNotPromoted = _resolver.flowAnalysis?.flow?.whyNotPromoted(operand);
 
-    _resolver.boolExpressionVerifier.checkForNonBoolNegationExpression(operand);
+    _resolver.boolExpressionVerifier.checkForNonBoolNegationExpression(operand,
+        whyNotPromoted: whyNotPromoted);
 
     _recordStaticType(node, _typeProvider.boolType);
 

pkg/analyzer/lib/src/error/bool_expression_verifier.dart

@@ -34,10 +34,12 @@ class BoolExpressionVerifier {
   /// error is reported on the expression.
   ///
   /// See [CompileTimeErrorCode.NON_BOOL_CONDITION].
-  void checkForNonBoolCondition(Expression condition) {
+  void checkForNonBoolCondition(Expression condition,
+      {required Map<DartType, NonPromotionReason> Function()? whyNotPromoted}) {
     checkForNonBoolExpression(
       condition,
       errorCode: CompileTimeErrorCode.NON_BOOL_CONDITION,
+      whyNotPromoted: whyNotPromoted,
     );
   }
 
@@ -46,7 +48,7 @@ class BoolExpressionVerifier {
   void checkForNonBoolExpression(Expression expression,
       {required ErrorCode errorCode,
       List<Object>? arguments,
-      Map<DartType, NonPromotionReason> Function()? whyNotPromoted}) {
+      required Map<DartType, NonPromotionReason> Function()? whyNotPromoted}) {
     var type = expression.typeOrThrow;
     if (!_checkForUseOfVoidResult(expression) &&
         !_resolver.typeSystem.isAssignableTo(type, _boolType)) {
@@ -63,10 +65,12 @@ class BoolExpressionVerifier {
   }
 
   /// Checks to ensure that the given [expression] is assignable to bool.
-  void checkForNonBoolNegationExpression(Expression expression) {
+  void checkForNonBoolNegationExpression(Expression expression,
+      {required Map<DartType, NonPromotionReason> Function()? whyNotPromoted}) {
     checkForNonBoolExpression(
       expression,
       errorCode: CompileTimeErrorCode.NON_BOOL_NEGATION_EXPRESSION,
+      whyNotPromoted: whyNotPromoted,
     );
   }
 

pkg/analyzer/lib/src/generated/resolver.dart

@@ -993,6 +993,7 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     boolExpressionVerifier.checkForNonBoolExpression(
       node.condition,
       errorCode: CompileTimeErrorCode.NON_BOOL_EXPRESSION,
+      whyNotPromoted: flowAnalysis?.flow?.whyNotPromoted(node.condition),
     );
     flowAnalysis?.flow?.assert_afterCondition(node.condition);
     node.message?.accept(this);
@@ -1007,6 +1008,7 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     boolExpressionVerifier.checkForNonBoolExpression(
       node.condition,
       errorCode: CompileTimeErrorCode.NON_BOOL_EXPRESSION,
+      whyNotPromoted: flowAnalysis?.flow?.whyNotPromoted(node.condition),
     );
     flowAnalysis?.flow?.assert_afterCondition(node.condition);
     node.message?.accept(this);
@@ -1187,7 +1189,9 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     // TODO(scheglov) Do we need these checks for null?
     condition.accept(this);
     condition = node.condition;
-    boolExpressionVerifier.checkForNonBoolCondition(condition);
+    var whyNotPromoted = flowAnalysis?.flow?.whyNotPromoted(condition);
+    boolExpressionVerifier.checkForNonBoolCondition(condition,
+        whyNotPromoted: whyNotPromoted);
 
     Expression thenExpression = node.thenExpression;
     InferenceContext.setTypeFromNode(thenExpression, node);
@@ -1349,7 +1353,9 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     InferenceContext.setType(condition, typeProvider.boolType);
     condition.accept(this);
     condition = node.condition;
-    boolExpressionVerifier.checkForNonBoolCondition(condition);
+    var whyNotPromoted = flowAnalysis?.flow?.whyNotPromoted(condition);
+    boolExpressionVerifier.checkForNonBoolCondition(condition,
+        whyNotPromoted: whyNotPromoted);
 
     flowAnalysis?.flow?.doStatement_end(condition);
   }
@@ -1598,8 +1604,10 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     InferenceContext.setType(condition, typeProvider.boolType);
     condition.accept(this);
     condition = node.condition;
+    var whyNotPromoted = flowAnalysis?.flow?.whyNotPromoted(condition);
 
-    boolExpressionVerifier.checkForNonBoolCondition(condition);
+    boolExpressionVerifier.checkForNonBoolCondition(condition,
+        whyNotPromoted: whyNotPromoted);
 
     CollectionElement thenElement = node.thenElement;
     if (flowAnalysis != null) {
@@ -1637,8 +1645,10 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
     InferenceContext.setType(condition, typeProvider.boolType);
     condition.accept(this);
     condition = node.condition;
+    var whyNotPromoted = flowAnalysis?.flow?.whyNotPromoted(condition);
 
-    boolExpressionVerifier.checkForNonBoolCondition(condition);
+    boolExpressionVerifier.checkForNonBoolCondition(condition,
+        whyNotPromoted: whyNotPromoted);
 
     Statement thenStatement = node.thenStatement;
     if (flowAnalysis != null) {
@@ -2172,8 +2182,11 @@ class ResolverVisitor extends ScopedVisitor with ErrorDetectionHelpers {
 
       flowAnalysis?.flow?.whileStatement_conditionBegin(node);
       condition.accept(this);
+      condition = node.condition;
+      var whyNotPromoted = flowAnalysis?.flow?.whyNotPromoted(condition);
 
-      boolExpressionVerifier.checkForNonBoolCondition(node.condition);
+      boolExpressionVerifier.checkForNonBoolCondition(node.condition,
+          whyNotPromoted: whyNotPromoted);
 
       Statement body = node.body;
       flowAnalysis?.flow?.whileStatement_bodyBegin(node, condition);