Resynthesize types of function typed formal parameters.

R=brianwilkerson@google.com, paulberry@google.com

Bug:
Change-Id: I1afb45879afc67806dfb3d6fe18b172fd2b3c01a
Reviewed-on: https://dart-review.googlesource.com/6645
Reviewed-by: Paul Berry <paulberry@google.com>

pkg/analyzer/lib/src/dart/element/element.dart

@@ -5322,6 +5322,11 @@ class FunctionTypeAliasElementImpl extends ElementImpl
 class GenericFunctionTypeElementImpl extends ElementImpl
     with TypeParameterizedElementMixin
     implements GenericFunctionTypeElement {
+  /**
+   * The kernel type.
+   */
+  final kernel.FunctionType _kernel;
+
   /**
    * The unlinked representation of the generic function type in the summary.
    */
@@ -5342,19 +5347,28 @@ class GenericFunctionTypeElementImpl extends ElementImpl
    */
   FunctionType _type;
 
+  /**
+   * Initialize using the given kernel.
+   */
+  GenericFunctionTypeElementImpl.forKernel(
+      ElementImpl enclosingElement, this._kernel)
+      : super.forSerialized(enclosingElement);
+
   /**
    * Initialize a newly created function element to have no name and the given
    * [nameOffset]. This is used for function expressions, that have no name.
    */
   GenericFunctionTypeElementImpl.forOffset(int nameOffset)
-      : super("", nameOffset);
+      : _kernel = null,
+        super("", nameOffset);
 
   /**
    * Initialize from serialized information.
    */
   GenericFunctionTypeElementImpl.forSerialized(
       ElementImpl enclosingElement, this._entityRef)
-      : super.forSerialized(enclosingElement);
+      : _kernel = null,
+        super.forSerialized(enclosingElement);
 
   @override
   TypeParameterizedElementMixin get enclosingTypeParameterContext {
@@ -5365,16 +5379,29 @@ class GenericFunctionTypeElementImpl extends ElementImpl
   String get identifier => '-';
 
   @override
-  List<kernel.TypeParameter> get kernelTypeParams => null;
+  List<kernel.TypeParameter> get kernelTypeParams => _kernel?.typeParameters;
 
   @override
   ElementKind get kind => ElementKind.GENERIC_FUNCTION_TYPE;
 
   @override
   List<ParameterElement> get parameters {
-    if (_entityRef != null) {
-      _parameters ??= ParameterElementImpl.resynthesizeList(
-          _entityRef.syntheticParams, this);
+    if (_parameters == null) {
+      if (_kernel != null) {
+        var parameters =
+            enclosingUnit._kernelContext.getFunctionTypeParameters(_kernel);
+        var positionalParameters = parameters[0];
+        var namedParameters = parameters[1];
+        _parameters = ParameterElementImpl.forKernelParameters(
+            this,
+            _kernel.requiredParameterCount,
+            positionalParameters,
+            namedParameters);
+      }
+      if (_entityRef != null) {
+        _parameters = ParameterElementImpl.resynthesizeList(
+            _entityRef.syntheticParams, this);
+      }
     }
     return _parameters ?? const <ParameterElement>[];
   }
@@ -5393,10 +5420,16 @@ class GenericFunctionTypeElementImpl extends ElementImpl
 
   @override
   DartType get returnType {
-    if (_entityRef != null && _returnType == null) {
-      _returnType = enclosingUnit.resynthesizerContext.resolveTypeRef(
-          this, _entityRef.syntheticReturnType,
-          defaultVoid: false, declaredType: true);
+    if (_returnType == null) {
+      if (_kernel != null) {
+        _returnType =
+            enclosingUnit._kernelContext.getType(this, _kernel.returnType);
+      }
+      if (_entityRef != null) {
+        _returnType = enclosingUnit.resynthesizerContext.resolveTypeRef(
+            this, _entityRef.syntheticReturnType,
+            defaultVoid: false, declaredType: true);
+      }
     }
     return _returnType;
   }
@@ -5412,7 +5445,7 @@ class GenericFunctionTypeElementImpl extends ElementImpl
 
   @override
   FunctionType get type {
-    if (_entityRef != null) {
+    if (_kernel != null || _entityRef != null) {
       _type ??= new FunctionTypeImpl.elementWithNameAndArgs(
           this, null, allEnclosingTypeParameterTypes, false);
     }
@@ -8463,7 +8496,6 @@ class ParameterElementImpl extends VariableElementImpl
    * been build yet, build them and remember in the corresponding fields.
    */
   void _resynthesizeTypeAndParameters() {
-    // TODO(scheglov) Don't resynthesize parameters.
     if (_kernel != null && _type == null) {
       kernel.DartType type = _kernel.type;
       _type = enclosingUnit._kernelContext.getType(this, type);

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

@@ -826,23 +826,29 @@ class _KernelUnitResynthesizerContextImpl
         return element.type;
       }
 
-      var functionElement = new FunctionElementImpl.synthetic([], null);
-      functionElement.enclosingElement = context;
+      if (context is ParameterElementImpl) {
+        var typeElement =
+            new GenericFunctionTypeElementImpl.forKernel(context, kernelType);
+        return typeElement.type;
+      } else {
+        var functionElement = new FunctionElementImpl.synthetic([], null);
+        functionElement.enclosingElement = context;
 
-      functionElement.typeParameters = kernelType.typeParameters.map((k) {
-        return new TypeParameterElementImpl.forKernel(functionElement, k);
-      }).toList(growable: false);
+        functionElement.typeParameters = kernelType.typeParameters.map((k) {
+          return new TypeParameterElementImpl.forKernel(functionElement, k);
+        }).toList(growable: false);
 
-      var parameters = getFunctionTypeParameters(kernelType);
-      functionElement.parameters = ParameterElementImpl.forKernelParameters(
-          functionElement,
-          kernelType.requiredParameterCount,
-          parameters[0],
-          parameters[1]);
+        var parameters = getFunctionTypeParameters(kernelType);
+        functionElement.parameters = ParameterElementImpl.forKernelParameters(
+            functionElement,
+            kernelType.requiredParameterCount,
+            parameters[0],
+            parameters[1]);
 
-      functionElement.returnType =
-          getType(functionElement, kernelType.returnType);
-      return functionElement.type;
+        functionElement.returnType =
+            getType(functionElement, kernelType.returnType);
+        return functionElement.type;
+      }
     }
 
     // TODO(scheglov) Support other kernel types.

pkg/analyzer/test/generated/non_error_resolver_kernel_test.dart

@@ -18,14 +18,6 @@ class NonErrorResolverTest_Kernel extends NonErrorResolverTest_Driver {
   @override
   bool get enableKernelDriver => true;
 
-  @override
-  @failingTest
-  test_argumentTypeNotAssignable_invocation_functionParameter_generic() async {
-    fail('This test fails only in checked mode.');
-    return super
-        .test_argumentTypeNotAssignable_invocation_functionParameter_generic();
-  }
-
   @override
   @failingTest
   test_async_flattened() async {
@@ -165,20 +157,6 @@ class NonErrorResolverTest_Kernel extends NonErrorResolverTest_Driver {
     return super.test_constWithUndefinedConstructor();
   }
 
-  @override
-  @failingTest
-  test_defaultValueInFunctionTypedParameter_named() async {
-    fail('This test fails only in checked mode.');
-    return super.test_defaultValueInFunctionTypedParameter_named();
-  }
-
-  @override
-  @failingTest
-  test_defaultValueInFunctionTypedParameter_optional() async {
-    fail('This test fails only in checked mode.');
-    return super.test_defaultValueInFunctionTypedParameter_optional();
-  }
-
   @override
   @failingTest
   test_deprecatedMemberUse_hide() async {
@@ -191,13 +169,6 @@ class NonErrorResolverTest_Kernel extends NonErrorResolverTest_Driver {
     return super.test_duplicateDefinition_emptyName();
   }
 
-  @override
-  @failingTest
-  test_fieldFormalParameter_functionTyped_named() async {
-    fail('This test fails only in checked mode.');
-    return super.test_fieldFormalParameter_functionTyped_named();
-  }
-
   @override
   @failingTest
   test_fieldInitializedInInitializerAndDeclaration_fieldNotFinal() async {
@@ -217,13 +188,6 @@ class NonErrorResolverTest_Kernel extends NonErrorResolverTest_Driver {
     return super.test_finalNotInitialized_fieldFormal();
   }
 
-  @override
-  @failingTest
-  test_finalNotInitialized_functionTypedFieldFormal() async {
-    fail('This test fails only in checked mode.');
-    return super.test_finalNotInitialized_functionTypedFieldFormal();
-  }
-
   @override
   @failingTest
   test_finalNotInitialized_hasNativeClause_hasConstructor() async {
@@ -671,29 +635,6 @@ class NonErrorResolverTest_Kernel extends NonErrorResolverTest_Driver {
     return super.test_staticAccessToInstanceMember_annotation();
   }
 
-  @override
-  @failingTest
-  test_typePromotion_booleanAnd_useInRight_accessedInClosureRight_noAssignment() async {
-    fail('This test fails only in checked mode.');
-    return super
-        .test_typePromotion_booleanAnd_useInRight_accessedInClosureRight_noAssignment();
-  }
-
-  @override
-  @failingTest
-  test_typePromotion_conditional_useInThen_accessedInClosure_noAssignment() async {
-    fail('This test fails only in checked mode.');
-    return super
-        .test_typePromotion_conditional_useInThen_accessedInClosure_noAssignment();
-  }
-
-  @override
-  @failingTest
-  test_typePromotion_if_accessedInClosure_noAssignment() async {
-    fail('This test fails only in checked mode.');
-    return super.test_typePromotion_if_accessedInClosure_noAssignment();
-  }
-
   @override
   @failingTest
   test_undefinedConstructorInInitializer_explicit_named() async {