Revert "First step toward resolving generic function types" (TBR)

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

Index: pkg/analyzer/lib/src/dart/element/type.dart
diff --git a/pkg/analyzer/lib/src/dart/element/type.dart b/pkg/analyzer/lib/src/dart/element/type.dart
index fb855cb88da8d9abfb710b111b87e53f2f0bdffe..3e40fb67421c0c72e1bf847ff641e1dbd5157c84 100644
--- a/pkg/analyzer/lib/src/dart/element/type.dart
+++ b/pkg/analyzer/lib/src/dart/element/type.dart
@@ -137,19 +137,9 @@ class CircularFunctionTypeImpl extends DynamicTypeImpl
       TypeParameterElement.EMPTY_LIST;
 
   @override
-  List<TypeParameterElement> get _explicitTypeParameters =>
-      TypeParameterElement.EMPTY_LIST;
-
-  @override
   bool get _isInstantiated => false;
 
   @override
-  List<ParameterElement> get _parameters => ParameterElement.EMPTY_LIST;
-
-  @override
-  DartType get _returnType => DynamicTypeImpl.instance;
-
-  @override
   List<DartType> get _typeArguments => DartType.EMPTY_LIST;
 
   @override
@@ -257,8 +247,7 @@ class DeferredFunctionTypeImpl extends FunctionTypeImpl {
 
   DeferredFunctionTypeImpl(this._computeElement, String name,
       List<DartType> typeArguments, bool isInstantiated)
-      : super._(
-            null, name, null, typeArguments, null, null, null, isInstantiated);
+      : super._(null, name, null, typeArguments, isInstantiated);
 
   @override
   FunctionTypedElement get element {
@@ -351,24 +340,6 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
   List<TypeParameterElement> _typeParameters;
 
   /**
-   * The list of [typeParameters], if there is no element from which they can be
-   * computed, or `null` if they should be computed when necessary.
-   */
-  final List<TypeParameterElement> _explicitTypeParameters;
-
-  /**
-   * The return type of the function, or `null` if the return type should be
-   * accessed through the element.
-   */
-  final DartType _returnType;
-
-  /**
-   * The parameters to the function, or `null` if the parameters should be
-   * accessed through the element.
-   */
-  final List<ParameterElement> _parameters;
-
-  /**
    * True if this type is the result of instantiating type parameters (and thus
    * any type parameters bound by the typedef should be considered part of
    * [typeParameters] rather than [typeFormals]).
@@ -388,7 +359,7 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
    */
   FunctionTypeImpl(ExecutableElement element,
       [List<FunctionTypeAliasElement> prunedTypedefs])
-      : this._(element, null, prunedTypedefs, null, null, null, null, false);
+      : this._(element, null, prunedTypedefs, null, false);
 
   /**
    * Initialize a newly created function type to be declared by the given
@@ -396,21 +367,7 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
    */
   FunctionTypeImpl.elementWithNameAndArgs(Element element, String name,
       List<DartType> typeArguments, bool isInstantiated)
-      : this._(element, name, null, typeArguments, null, null, null,
-            isInstantiated);
-
-  /**
-   * Initialize a newly created function type to represent a type described by
-   * a generic function type.
-   */
-  FunctionTypeImpl.forGenericFunctionType(
-      List<TypeParameterElement> typeParameters,
-      List<DartType> typeArguments,
-      DartType returnType,
-      List<ParameterElement> parameters,
-      bool isInstantiated)
-      : this._(null, null, null, typeArguments, typeParameters, returnType,
-            parameters, isInstantiated);
+      : this._(element, name, null, typeArguments, isInstantiated);
 
   /**
    * Initialize a newly created function type to be declared by the given
@@ -418,34 +375,24 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
    */
   FunctionTypeImpl.forTypedef(FunctionTypeAliasElement element,
       [List<FunctionTypeAliasElement> prunedTypedefs])
-      : this._(element, element?.name, prunedTypedefs, null, null, null, null,
-            false);
+      : this._(element, element?.name, prunedTypedefs, null, false);
 
   /**
    * Private constructor.
    */
-  FunctionTypeImpl._(
-      TypeParameterizedElement element,
-      String name,
-      this.prunedTypedefs,
-      this._typeArguments,
-      this._explicitTypeParameters,
-      this._returnType,
-      this._parameters,
-      this._isInstantiated)
-      : _typeParameters = _explicitTypeParameters,
-        super(element, name);
+  FunctionTypeImpl._(TypeParameterizedElement element, String name,
+      this.prunedTypedefs, this._typeArguments, this._isInstantiated)
+      : super(element, name);
 
   /**
    * Return the base parameter elements of this function element.
    */
-  List<ParameterElement> get baseParameters =>
-      _parameters ?? element.parameters;
+  List<ParameterElement> get baseParameters => element.parameters;
 
   /**
    * Return the return type defined by this function's element.
    */
-  DartType get baseReturnType => _returnType ?? element.returnType;
+  DartType get baseReturnType => element.returnType;
 
   @deprecated
   @override
@@ -854,8 +801,8 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
     newTypeArgs.addAll(typeArguments);
     newTypeArgs.addAll(argumentTypes);
 
-    return new FunctionTypeImpl._(element, name, prunedTypedefs, newTypeArgs,
-        _explicitTypeParameters, _returnType, _parameters, true);
+    return new FunctionTypeImpl._(
+        element, name, prunedTypedefs, newTypeArgs, true);
   }
 
   @override
@@ -904,8 +851,8 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
       List<DartType> typeArgs = typeArguments
           .map((DartType t) => (t as TypeImpl).pruned(prune))
           .toList(growable: false);
-      return new FunctionTypeImpl._(element, name, prune, typeArgs,
-          _explicitTypeParameters, _returnType, _parameters, _isInstantiated);
+      return new FunctionTypeImpl._(
+          element, name, prune, typeArgs, _isInstantiated);
     }
   }
 
@@ -931,8 +878,8 @@ class FunctionTypeImpl extends TypeImpl implements FunctionType {
     }
     List<DartType> typeArgs =
         TypeImpl.substitute(typeArguments, argumentTypes, parameterTypes);
-    return new FunctionTypeImpl._(element, name, prune, typeArgs,
-        _explicitTypeParameters, _returnType, _parameters, _isInstantiated);
+    return new FunctionTypeImpl._(
+        element, name, prune, typeArgs, _isInstantiated);
   }
 
   @override