Issue 32114. Fix instantiating typedefs to bounds.

[email protected]

Bug: #32114
Change-Id: I215eafb6314fe265d4809ff6ed80e4a567365a4f
Reviewed-on: https://dart-review.googlesource.com/46381
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -94,7 +94,7 @@ class AnalysisDriver implements AnalysisDriverGeneric {
   /**
    * The version of data format, should be incremented on every format change.
    */
-  static const int DATA_VERSION = 50;
+  static const int DATA_VERSION = 51;
 
   /**
    * The number of exception contexts allowed to write. Once this field is

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

@@ -8397,7 +8397,9 @@ class TypeNameResolver {
       }
     } else {
       if (element is GenericTypeAliasElementImpl) {
-        type = element.typeAfterSubstitution(null) ?? dynamicType;
+        List<DartType> typeArguments =
+            typeSystem.instantiateTypeFormalsToBounds(element.typeParameters);
+        type = element.typeAfterSubstitution(typeArguments) ?? dynamicType;
       } else {
         type = typeSystem.instantiateToBounds(type);
       }

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

@@ -309,9 +309,28 @@ class StrongTypeSystemImpl extends TypeSystem {
   DartType instantiateToBounds(DartType type,
       {List<bool> hasError, Map<TypeParameterType, DartType> knownTypes}) {
     List<TypeParameterElement> typeFormals = typeFormalsAsElements(type);
+    List<DartType> arguments = instantiateTypeFormalsToBounds(typeFormals,
+        hasError: hasError, knownTypes: knownTypes);
+    if (arguments == null) {
+      return type;
+    }
+
+    return instantiateType(type, arguments);
+  }
+
+  /**
+   * Given uninstantiated [typeFormals], instantiate them to their bounds.
+   * See the issue for the algorithm description.
+   *
+   * https://github.com/dart-lang/sdk/issues/27526#issuecomment-260021397
+   */
+  List<DartType> instantiateTypeFormalsToBounds(
+      List<TypeParameterElement> typeFormals,
+      {List<bool> hasError,
+      Map<TypeParameterType, DartType> knownTypes}) {
     int count = typeFormals.length;
     if (count == 0) {
-      return type;
+      return null;
     }
 
     Set<TypeParameterType> all = new Set<TypeParameterType>();
@@ -394,7 +413,7 @@ class StrongTypeSystemImpl extends TypeSystem {
 
     List<DartType> orderedArguments =
         typeFormals.map((p) => defaults[p.type]).toList();
-    return instantiateType(type, orderedArguments);
+    return orderedArguments;
   }
 
   @override
@@ -1222,6 +1241,13 @@ abstract class TypeSystem {
     }
   }
 
+  /**
+   * Given uninstantiated [typeFormals], instantiate them to their bounds.
+   */
+  List<DartType> instantiateTypeFormalsToBounds(
+      List<TypeParameterElement> typeFormals,
+      {List<bool> hasError});
+
   /**
    * Return `true` if the [leftType] is assignable to the [rightType] (that is,
    * if leftType <==> rightType).
@@ -1530,6 +1556,13 @@ class TypeSystemImpl extends TypeSystem {
     return type;
   }
 
+  @override
+  List<DartType> instantiateTypeFormalsToBounds(
+      List<TypeParameterElement> typeFormals,
+      {List<bool> hasError}) {
+    return null;
+  }
+
   @override
   bool isAssignableTo(DartType leftType, DartType rightType,
       {bool isDeclarationCast = false}) {

pkg/analyzer/lib/src/summary/resynthesize.dart

@@ -1299,9 +1299,32 @@ class _ReferenceInfo {
       return type;
     } else if (element is GenericTypeAliasElementHandle) {
       GenericTypeAliasElementImpl actualElement = element.actualElement;
-      List<DartType> argumentTypes =
-          new List.generate(numTypeArguments, getTypeArgument);
-      return actualElement.typeAfterSubstitution(argumentTypes);
+      List<DartType> typeArguments;
+      if (numTypeArguments == numTypeParameters) {
+        typeArguments = _buildTypeArguments(numTypeArguments, getTypeArgument);
+      } else if (libraryResynthesizer.summaryResynthesizer.strongMode &&
+          instantiateToBoundsAllowed) {
+        if (!_isBeingInstantiatedToBounds) {
+          _isBeingInstantiatedToBounds = true;
+          _isRecursiveWhileInstantiateToBounds = false;
+          try {
+            typeArguments = libraryResynthesizer
+                .summaryResynthesizer.context.typeSystem
+                .instantiateTypeFormalsToBounds(element.typeParameters);
+            if (_isRecursiveWhileInstantiateToBounds) {
+              typeArguments = _dynamicTypeArguments;
+            }
+          } finally {
+            _isBeingInstantiatedToBounds = false;
+          }
+        } else {
+          _isRecursiveWhileInstantiateToBounds = true;
+          typeArguments = _dynamicTypeArguments;
+        }
+      } else {
+        typeArguments = _dynamicTypeArguments;
+      }
+      return actualElement.typeAfterSubstitution(typeArguments);
     } else if (element is FunctionTypedElement) {
       if (element is FunctionTypeAliasElementHandle) {
         List<DartType> typeArguments;

pkg/analyzer/test/src/summary/resynthesize_ast_test.dart

@@ -66,12 +66,6 @@ class ResynthesizeAstStrongTest extends _ResynthesizeAstTest {
   test_const_constructor_inferred_args() =>
       test_const_constructor_inferred_args();
 
-  @override
-  @failingTest
-  test_instantiateToBounds_functionTypeAlias_simple() async {
-    await super.test_instantiateToBounds_functionTypeAlias_simple();
-  }
-
   @override
   @failingTest
   test_syntheticFunctionType_genericClosure() async {

pkg/analyzer/test/src/task/strong/checker_test.dart

@@ -1293,7 +1293,6 @@ void main() {
 ''');
   }
 
-  @failingTest
   test_fuzzyArrowLegacyAssignability_GlobalInference() async {
     // Test for legacy fuzzy arrow support on assignability, pending
     // cleanup.  https://github.com/dart-lang/sdk/issues/29630