Add support for parsing annotations with Fasta.

[email protected], [email protected]
BUG=

Review-Url: https://codereview.chromium.org/2748763003 .

Author: scheglov

pkg/analyzer/test/generated/parser_test.dart

@@ -13315,6 +13315,56 @@ abstract class TopLevelParserTestMixin implements AbstractParserTestCase {
     expect(declaration.typeParameters, isNull);
   }
 
+  void test_parseClassDeclaration_metadata() {
+    createParser('@A @B(2) @C.foo(3) @d.E.bar(4, 5) class X {}');
+    var declaration = parseFullCompilationUnitMember() as ClassDeclaration;
+    expect(declaration.metadata, hasLength(4));
+
+    {
+      var annotation = declaration.metadata[0];
+      expect(annotation.atSign, isNotNull);
+      expect(annotation.name, new isInstanceOf<SimpleIdentifier>());
+      expect(annotation.name.name, 'A');
+      expect(annotation.period, isNull);
+      expect(annotation.constructorName, isNull);
+      expect(annotation.arguments, isNull);
+    }
+
+    {
+      var annotation = declaration.metadata[1];
+      expect(annotation.atSign, isNotNull);
+      expect(annotation.name, new isInstanceOf<SimpleIdentifier>());
+      expect(annotation.name.name, 'B');
+      expect(annotation.period, isNull);
+      expect(annotation.constructorName, isNull);
+      expect(annotation.arguments, isNotNull);
+      expect(annotation.arguments.arguments, hasLength(1));
+    }
+
+    {
+      var annotation = declaration.metadata[2];
+      expect(annotation.atSign, isNotNull);
+      expect(annotation.name, new isInstanceOf<PrefixedIdentifier>());
+      expect(annotation.name.name, 'C.foo');
+      expect(annotation.period, isNull);
+      expect(annotation.constructorName, isNull);
+      expect(annotation.arguments, isNotNull);
+      expect(annotation.arguments.arguments, hasLength(1));
+    }
+
+    {
+      var annotation = declaration.metadata[3];
+      expect(annotation.atSign, isNotNull);
+      expect(annotation.name, new isInstanceOf<PrefixedIdentifier>());
+      expect(annotation.name.name, 'd.E');
+      expect(annotation.period, isNotNull);
+      expect(annotation.constructorName, isNotNull);
+      expect(annotation.constructorName.name, 'bar');
+      expect(annotation.arguments, isNotNull);
+      expect(annotation.arguments.arguments, hasLength(2));
+    }
+  }
+
   void test_parseClassDeclaration_native() {
     createParser('class A native "nativeValue" {}');
     CompilationUnitMember member = parseFullCompilationUnitMember();

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

@@ -1470,6 +1470,21 @@ class AstBuilder extends ScopeListener {
     }
   }
 
+  @override
+  void endMetadata(Token beginToken, Token periodBeforeName, Token endToken) {
+    debugEvent("Metadata");
+    MethodInvocation invocation = pop();
+    SimpleIdentifier constructorName = periodBeforeName != null ? pop() : null;
+    pop(); // Type arguments, not allowed.
+    Identifier name = pop();
+    push(ast.annotation(
+        toAnalyzerToken(beginToken),
+        name,
+        toAnalyzerToken(periodBeforeName),
+        constructorName,
+        invocation?.argumentList));
+  }
+
   ParameterKind _toAnalyzerParameterKind(FormalParameterType type) {
     if (type == FormalParameterType.POSITIONAL) {
       return ParameterKind.POSITIONAL;