Augment. Report AUGMENTATION_TYPE_PARAMETER_COUNT.

Change-Id: Iafd5613c7ed87f9f9aff244f0852a663bb45d642
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/372562
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analysis_server/lib/src/services/correction/error_fix_status.yaml

@@ -211,6 +211,8 @@ CompileTimeErrorCode.AUGMENTATION_MODIFIER_MISSING:
   status: needsFix
 CompileTimeErrorCode.AUGMENTATION_OF_DIFFERENT_DECLARATION_KIND:
   status: noFix
+CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT:
+  status: noFix
 CompileTimeErrorCode.AUGMENTATION_WITHOUT_DECLARATION:
   status: noFix
 CompileTimeErrorCode.AUGMENTATION_WITHOUT_IMPORT:

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

@@ -305,6 +305,15 @@ class ClassElementImpl extends ClassOrMixinElementImpl
     return augmentedInternal;
   }
 
+  AugmentedClassElementImpl? get augmentedIfReally {
+    if (augmentationTarget != null) {
+      if (augmented case AugmentedClassElementImpl augmented) {
+        return augmented;
+      }
+    }
+    return null;
+  }
+
   @override
   set constructors(List<ConstructorElementImpl> constructors) {
     assert(!isMixinApplication);
@@ -2734,6 +2743,15 @@ class EnumElementImpl extends InterfaceElementImpl
     return augmentedInternal;
   }
 
+  AugmentedEnumElementImpl? get augmentedIfReally {
+    if (augmentationTarget != null) {
+      if (augmented case AugmentedEnumElementImpl augmented) {
+        return augmented;
+      }
+    }
+    return null;
+  }
+
   List<FieldElementImpl> get constants {
     return fields.where((field) => field.isEnumConstant).toList();
   }
@@ -2972,6 +2990,15 @@ class ExtensionElementImpl extends InstanceElementImpl
     return augmentedInternal;
   }
 
+  AugmentedExtensionElementImpl? get augmentedIfReally {
+    if (augmentationTarget != null) {
+      if (augmented case AugmentedExtensionElementImpl augmented) {
+        return augmented;
+      }
+    }
+    return null;
+  }
+
   @override
   List<Element> get children => [
         ...super.children,
@@ -3090,6 +3117,15 @@ class ExtensionTypeElementImpl extends InterfaceElementImpl
     return augmentedInternal;
   }
 
+  AugmentedExtensionTypeElementImpl? get augmentedIfReally {
+    if (augmentationTarget != null) {
+      if (augmented case AugmentedExtensionTypeElementImpl augmented) {
+        return augmented;
+      }
+    }
+    return null;
+  }
+
   @override
   ElementKind get kind {
     return ElementKind.EXTENSION_TYPE;
@@ -5358,6 +5394,15 @@ class MixinElementImpl extends ClassOrMixinElementImpl
     return augmentedInternal;
   }
 
+  AugmentedMixinElementImpl? get augmentedIfReally {
+    if (augmentationTarget != null) {
+      if (augmented case AugmentedMixinElementImpl augmented) {
+        return augmented;
+      }
+    }
+    return null;
+  }
+
   @override
   bool get isBase {
     return hasModifier(Modifier.BASE);

pkg/analyzer/lib/src/error/codes.g.dart

@@ -257,6 +257,16 @@ class CompileTimeErrorCode extends AnalyzerErrorCode {
         "Try changing the augmentation to match the declaration kind.",
   );
 
+  static const CompileTimeErrorCode AUGMENTATION_TYPE_PARAMETER_COUNT =
+      CompileTimeErrorCode(
+    'AUGMENTATION_TYPE_PARAMETER_COUNT',
+    "The augmentation must have the same number of type parameters as the "
+        "declaration.",
+    correctionMessage:
+        "Try changing the augmentation to match the declaration type "
+        "parameters.",
+  );
+
   static const CompileTimeErrorCode AUGMENTATION_WITHOUT_DECLARATION =
       CompileTimeErrorCode(
     'AUGMENTATION_WITHOUT_DECLARATION',

pkg/analyzer/lib/src/error/error_code_values.g.dart

@@ -67,6 +67,7 @@ const List<ErrorCode> errorCodeValues = [
   CompileTimeErrorCode.AUGMENTATION_MODIFIER_EXTRA,
   CompileTimeErrorCode.AUGMENTATION_MODIFIER_MISSING,
   CompileTimeErrorCode.AUGMENTATION_OF_DIFFERENT_DECLARATION_KIND,
+  CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT,
   CompileTimeErrorCode.AUGMENTATION_WITHOUT_DECLARATION,
   CompileTimeErrorCode.AUGMENTATION_WITHOUT_IMPORT,
   CompileTimeErrorCode.AUGMENTATION_WITHOUT_LIBRARY,

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

@@ -459,6 +459,14 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         augmentationElement: element,
       );
 
+      if (element.augmentedIfReally case var augmented?) {
+        _checkAugmentationTypeParameters(
+          nameToken: node.name,
+          typeParameterList: node.typeParameters,
+          declarationTypeParameters: augmented.declaration.typeParameters,
+        );
+      }
+
       _checkClassAugmentationTargetAlreadyHasExtendsClause(
         node: node,
         augmentationTarget: element.augmentationTarget,
@@ -662,6 +670,14 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         element: element,
       );
 
+      if (element.augmentedIfReally case var augmented?) {
+        _checkAugmentationTypeParameters(
+          nameToken: node.name,
+          typeParameterList: node.typeParameters,
+          declarationTypeParameters: augmented.declaration.typeParameters,
+        );
+      }
+
       var augmented = element.augmented;
       var declarationElement = augmented.declaration;
       _enclosingClass = declarationElement;
@@ -738,6 +754,16 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
       element: element,
     );
 
+    if (element.augmentedIfReally case var augmented?) {
+      if (node.name case var nameToken?) {
+        _checkAugmentationTypeParameters(
+          nameToken: nameToken,
+          typeParameterList: node.typeParameters,
+          declarationTypeParameters: augmented.declaration.typeParameters,
+        );
+      }
+    }
+
     _enclosingExtension = element;
     _duplicateDefinitionVerifier.checkExtension(node);
     _checkForConflictingExtensionTypeVariableErrorCodes();
@@ -771,6 +797,14 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         element: element,
       );
 
+      if (element.augmentedIfReally case var augmented?) {
+        _checkAugmentationTypeParameters(
+          nameToken: node.name,
+          typeParameterList: node.typeParameters,
+          declarationTypeParameters: augmented.declaration.typeParameters,
+        );
+      }
+
       _enclosingClass = declarationElement;
 
       _checkForBuiltInIdentifierAsName(node.name,
@@ -1185,6 +1219,14 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
         augmentationElement: element,
       );
 
+      if (element.augmentedIfReally case var augmented?) {
+        _checkAugmentationTypeParameters(
+          nameToken: node.name,
+          typeParameterList: node.typeParameters,
+          declarationTypeParameters: augmented.declaration.typeParameters,
+        );
+      }
+
       var augmented = element.augmented;
       var declarationElement = augmented.declaration;
       _enclosingClass = declarationElement;
@@ -1629,6 +1671,45 @@ class ErrorVerifier extends RecursiveAstVisitor<void>
     );
   }
 
+  void _checkAugmentationTypeParameters({
+    required Token nameToken,
+    required TypeParameterList? typeParameterList,
+    required List<TypeParameterElement> declarationTypeParameters,
+  }) {
+    if (declarationTypeParameters.isEmpty) {
+      if (typeParameterList != null) {
+        errorReporter.atToken(
+          typeParameterList.leftBracket,
+          CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT,
+        );
+      }
+    } else {
+      if (typeParameterList == null) {
+        errorReporter.atToken(
+          nameToken,
+          CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT,
+        );
+      } else {
+        var declarationCount = declarationTypeParameters.length;
+        var typeParameters = typeParameterList.typeParameters;
+        switch (typeParameters.length.compareTo(declarationCount)) {
+          case < 0:
+            errorReporter.atToken(
+              typeParameterList.rightBracket,
+              CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT,
+            );
+          case > 0:
+            errorReporter.atToken(
+              typeParameters[declarationCount].name,
+              CompileTimeErrorCode.AUGMENTATION_TYPE_PARAMETER_COUNT,
+            );
+          default:
+          // TODO(scheglov): check names and bounds
+        }
+      }
+    }
+  }
+
   void _checkClassAugmentationModifiers({
     required Token? augmentKeyword,
     required ClassDeclarationImpl augmentationNode,

pkg/analyzer/messages.yaml

@@ -1154,6 +1154,10 @@ CompileTimeErrorCode:
       Parameters:
       0: the name of the declaration kind.
       1: the name of the augmentation kind.
+  AUGMENTATION_TYPE_PARAMETER_COUNT:
+    problemMessage: The augmentation must have the same number of type parameters as the declaration.
+    correctionMessage: Try changing the augmentation to match the declaration type parameters.
+    hasPublishedDocs: false
   AUGMENTATION_WITHOUT_DECLARATION:
     problemMessage: The declaration being augmented doesn't exist.
     correctionMessage: Try changing the augmentation to match an existing declaration.