Implement generalized function types.

pkg/analyzer/lib/src/fasta/ast_builder.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library fasta.analyzer.ast_builder;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/ast/ast_factory.dart' show AstFactory;
 import 'package:analyzer/dart/ast/standard_ast_factory.dart' as standard;
 import 'package:analyzer/dart/ast/token.dart' as analyzer show Token;
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
 import 'package:analyzer/dart/element/element.dart' show Element;
 import 'package:front_end/src/fasta/parser/parser.dart'
-    show FormalParameterType, Parser;
+    show FormalParameterType, MemberKind, Parser;
 import 'package:front_end/src/fasta/scanner/string_scanner.dart';
 import 'package:front_end/src/fasta/scanner/token.dart'
     show BeginGroupToken, CommentToken;
 import 'package:front_end/src/scanner/token.dart' as analyzer;
 
 import 'package:front_end/src/fasta/errors.dart' show internalError;
 import 'package:front_end/src/fasta/fasta_codes.dart'
     show FastaMessage, codeExpectedExpression, codeExpectedFunctionBody;
 import 'package:front_end/src/fasta/kernel/kernel_builder.dart'
     show Builder, KernelLibraryBuilder, ProcedureBuilder, Scope;
@@ skipping 819 matching lines @@
               variableList.keyword,
               variableList.type,
               variableList.variables.single.name),
           toAnalyzerToken(inKeyword),
           iterator,
           toAnalyzerToken(rightParenthesis),
           body));
     }
   }
 
-  void endFormalParameter(Token covariantKeyword, Token thisKeyword,
-      Token nameToken, FormalParameterType kind) {
+  void endFormalParameter(Token thisKeyword, Token nameToken,
+      FormalParameterType kind, MemberKind memberKind) {
     debugEvent("FormalParameter");
     _ParameterDefaultValue defaultValue = pop();
 
     AstNode nameOrFunctionTypedParameter = pop();
 
     FormalParameter node;
     SimpleIdentifier name;
     if (nameOrFunctionTypedParameter is FormalParameter) {
       node = nameOrFunctionTypedParameter;
       name = nameOrFunctionTypedParameter.identifier;
     } else {
       name = nameOrFunctionTypedParameter;
       TypeAnnotation type = pop();
       _Modifiers modifiers = pop();
       Token keyword = modifiers?.finalConstOrVarKeyword;
+      Token covariantKeyword = modifiers?.covariantKeyword;
       pop(); // TODO(paulberry): Metadata.
       Comment comment = pop();
       if (thisKeyword == null) {
         node = ast.simpleFormalParameter2(
             comment: comment,
             covariantKeyword: toAnalyzerToken(covariantKeyword),
             keyword: toAnalyzerToken(keyword),
             type: type,
             identifier: name);
       } else {
@@ skipping 20 matching lines @@
 
     if (name != null) {
       scope[name.name] =
           name.staticElement = new AnalyzerParameterElement(node);
     }
     push(node);
   }
 
   @override
   void endFunctionTypedFormalParameter(
-      Token covariantKeyword, Token thisKeyword, FormalParameterType kind) {
+      Token thisKeyword, FormalParameterType kind) {
     debugEvent("FunctionTypedFormalParameter");
 
     FormalParameterList formalParameters = pop();
     TypeParameterList typeParameters = pop();
     SimpleIdentifier name = pop();
     TypeAnnotation returnType = pop();
 
-    {
-      _Modifiers modifiers = pop();
-      if (modifiers != null) {
-        // TODO(scheglov): Report error.
-        internalError('Unexpected modifier. Report an error.');
-      }
-    }
+    _Modifiers modifiers = pop();
+    Token covariantKeyword = modifiers?.covariantKeyword;
 
     pop(); // TODO(paulberry): Metadata.
     Comment comment = pop();
 
     FormalParameter node;
     if (thisKeyword == null) {
       node = ast.functionTypedFormalParameter2(
           comment: comment,
           covariantKeyword: toAnalyzerToken(covariantKeyword),
           returnType: returnType,
@@ skipping 13 matching lines @@
           period: toAnalyzerToken(period),
           identifier: name,
           typeParameters: typeParameters,
           parameters: formalParameters);
     }
 
     scope[name.name] = name.staticElement = new AnalyzerParameterElement(node);
     push(node);
   }
 
-  void endFormalParameters(int count, Token beginToken, Token endToken) {
+  void endFormalParameters(
+      int count, Token beginToken, Token endToken, MemberKind kind) {
     debugEvent("FormalParameters");
     List rawParameters = popList(count) ?? const <Object>[];
     List<FormalParameter> parameters = <FormalParameter>[];
     Token leftDelimiter;
     Token rightDelimiter;
     for (Object raw in rawParameters) {
       if (raw is _OptionalFormalParameters) {
         parameters.addAll(raw.parameters);
         leftDelimiter = raw.leftDelimiter;
         rightDelimiter = raw.rightDelimiter;
@@ skipping 857 matching lines @@
 
   @override
   void endTypeArguments(int count, Token beginToken, Token endToken) {
     debugEvent("TypeArguments");
     List<TypeAnnotation> arguments = popList(count);
     push(ast.typeArgumentList(
         toAnalyzerToken(beginToken), arguments, toAnalyzerToken(endToken)));
   }
 
   @override
-  void endFields(
-      int count, Token covariantKeyword, Token beginToken, Token endToken) {
+  void endFields(int count, Token beginToken, Token endToken) {
     debugEvent("Fields");
     List<VariableDeclaration> variables = popList(count);
     TypeAnnotation type = pop();
     _Modifiers modifiers = pop();
     var variableList = ast.variableDeclarationList(null, null,
         toAnalyzerToken(modifiers?.finalConstOrVarKeyword), type, variables);
+    Token covariantKeyword = modifiers?.covariantKeyword;
     List<Annotation> metadata = pop();
     Comment comment = pop();
     push(ast.fieldDeclaration2(
         comment: comment,
         metadata: metadata,
         covariantKeyword: toAnalyzerToken(covariantKeyword),
         staticKeyword: toAnalyzerToken(modifiers?.staticKeyword),
         fieldList: variableList,
         semicolon: toAnalyzerToken(endToken)));
   }
@@ skipping 207 matching lines @@
   _OperatorName(this.operatorKeyword, this.name);
 }
 
 /// Data structure placed on the stack to represent a non-empty sequence
 /// of modifiers.
 class _Modifiers {
   Token abstractKeyword;
   Token externalKeyword;
   Token finalConstOrVarKeyword;
   Token staticKeyword;
+  Token covariantKeyword;
 
   _Modifiers(List<Token> modifierTokens) {
     // No need to check the order and uniqueness of the modifiers, or that
     // disallowed modifiers are not used; the parser should do that.
     // TODO(paulberry,ahe): implement the necessary logic in the parser.
     for (var token in modifierTokens) {
       var s = token.lexeme;
       if (identical('abstract', s)) {
         abstractKeyword = token;
       } else if (identical('const', s)) {
         finalConstOrVarKeyword = token;
       } else if (identical('external', s)) {
         externalKeyword = token;
       } else if (identical('final', s)) {
         finalConstOrVarKeyword = token;
       } else if (identical('static', s)) {
         staticKeyword = token;
       } else if (identical('var', s)) {
         finalConstOrVarKeyword = token;
+      } else if (identical('covariant', s)) {
+        covariantKeyword = token;
       } else {
         internalError('Unhandled modifier: $s');
       }
     }
   }
 }