Validate local resolution scope, and compute initial name scope.

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

Review URL: https://codereview.chromium.org/2439583003 .

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

@@ -9395,6 +9395,10 @@ enum TypeResolverMode {
 
   /**
    * Resolve only type names that would be skipped during [api].
+   *
+   * Resolution must start from a unit member or a class member. For example
+   * it is not allowed to resolve types in a separate statement, or a function
+   * body.
    */
   local
 }
@@ -9438,7 +9442,16 @@ class TypeResolverVisitor extends ScopedVisitor {
 
   final TypeResolverMode mode;
 
-  bool _visitAllInLocalMode = false;
+  /**
+   * Is `true` when we are visiting all nodes in [TypeResolverMode.local] mode.
+   */
+  bool _localModeVisitAll = false;
+
+  /**
+   * Is `true` if we are in [TypeResolverMode.local] mode, and the initial
+   * [nameScope] was computed.
+   */
+  bool _localModeScopeReady = false;
 
   /**
    * Initialize a newly created visitor to resolve the nodes in an AST node.
@@ -9794,21 +9807,47 @@ class TypeResolverVisitor extends ScopedVisitor {
     // resolve only type names that are local.
     if (mode == TypeResolverMode.local) {
       // We are in the state of visiting all nodes.
-      if (_visitAllInLocalMode) {
+      if (_localModeVisitAll) {
         return super.visitNode(node);
       }
 
+      // Ensure that the name scope is ready.
+      if (!_localModeScopeReady) {
+        void fillNameScope(AstNode node) {
+          if (node is FunctionBody ||
+              node is FormalParameterList ||
+              node is VariableDeclaration) {
+            throw new StateError(
+                'Local type resolution must start from a class or unit member.');
+          }
+          // Create enclosing name scopes.
+          AstNode parent = node.parent;
+          if (parent != null) {
+            fillNameScope(parent);
+          }
+          // Create the name scope for the node.
+          if (node is ClassDeclaration) {
+            ClassElement classElement = node.element;
+            nameScope = new TypeParameterScope(nameScope, classElement);
+            nameScope = new ClassScope(nameScope, classElement);
+          }
+        }
+
+        fillNameScope(node);
+        _localModeScopeReady = true;
+      }
+
       /**
        * Visit the given [node] and all its children.
        */
       void visitAllNodes(AstNode node) {
         if (node != null) {
-          bool wasVisitAllInLocalMode = _visitAllInLocalMode;
+          bool wasVisitAllInLocalMode = _localModeVisitAll;
           try {
-            _visitAllInLocalMode = true;
+            _localModeVisitAll = true;
             node.accept(this);
           } finally {
-            _visitAllInLocalMode = wasVisitAllInLocalMode;
+            _localModeVisitAll = wasVisitAllInLocalMode;
           }
         }
       }

pkg/analyzer/test/generated/parser_test.dart

@@ -8,10 +8,12 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/error/error.dart';
+import 'package:analyzer/error/listener.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/generated/parser.dart';
+import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/testing/ast_factory.dart';
 import 'package:analyzer/src/generated/testing/token_factory.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
@@ -2986,6 +2988,21 @@ class ParserTestCase extends EngineTestCase {
     return unit;
   }
 
+  /**
+   * Parse the given [code] as a compilation unit.
+   */
+  static CompilationUnit parseCompilationUnit2(String code,
+      {AnalysisErrorListener listener, bool parseGenericMethods: false}) {
+    listener ??= AnalysisErrorListener.NULL_LISTENER;
+    Scanner scanner = new Scanner(null, new CharSequenceReader(code), listener);
+    Token token = scanner.tokenize();
+    Parser parser = new Parser(null, listener);
+    parser.parseGenericMethods = parseGenericMethods;
+    CompilationUnit unit = parser.parseCompilationUnit(token);
+    unit.lineInfo = new LineInfo(scanner.lineStarts);
+    return unit;
+  }
+
   /**
    * Parse the given [source] as a statement. The [errorCodes] are the error
    * codes of the errors that are expected to be found. If

pkg/analyzer/test/generated/resolver_test.dart

@@ -2695,7 +2695,9 @@ A V = new A();
   }
 
   void test_modeLocal_noContext() {
-    CompilationUnit unit = ParserTestCase.parseCompilationUnit(r'''
+    CompilationUnit unit;
+    _resolveTypeModeLocal(
+        r'''
 class C {
   A f = new A();
   A m([A p = const A()]) {
@@ -2710,31 +2712,10 @@ A f([A p = const A()]) {
 }
 A V = new A();
 A get G => new A();
-''');
-    var unitElement = new CompilationUnitElementImpl('/test.dart');
-    ClassElementImpl A = ElementFactory.classElement2('A');
-
-    // Build API elements.
-    {
-      var holder = new ElementHolder();
-      unit.accept(new ElementBuilder(holder, unitElement));
-    }
-
-    // Resolve API types.
-    {
-      MemoryResourceProvider resourceProvider = new MemoryResourceProvider();
-      InternalAnalysisContext context = AnalysisContextFactory.contextWithCore(
-          resourceProvider: resourceProvider);
-      var source = resourceProvider.getFile('/test.dart').createSource();
-      var libraryElement = new LibraryElementImpl.forNode(context, null)
-        ..definingCompilationUnit = unitElement;
-      var libraryScope = new LibraryScope(libraryElement);
-      var visitor = new TypeResolverVisitor(
-          libraryElement, source, _typeProvider, _listener,
-          nameScope: libraryScope, mode: TypeResolverMode.local);
-      libraryScope.define(A);
-      unit.accept(visitor);
-    }
+''', (CompilationUnit u) {
+      unit = u;
+      return u;
+    });
 
     // Top-level: C
     {
@@ -2827,6 +2808,185 @@ A get G => new A();
     }
   }
 
+  void test_modeLocal_withContext_bad_methodBody() {
+    expect(() {
+      _resolveTypeModeLocal(
+          r'''
+class C<T1> {
+  A m<T2>() {
+    T1 v1;
+    T2 v2;
+  }
+}
+''', (CompilationUnit u) {
+        var c = u.declarations[0] as ClassDeclaration;
+        var m = c.members[0] as MethodDeclaration;
+        var mb = m.body as BlockFunctionBody;
+        return mb;
+      });
+    }, throwsStateError);
+  }
+
+  void test_modeLocal_withContext_bad_topLevelVariable_declaration() {
+    expect(() {
+      _resolveTypeModeLocal(
+          r'''
+var v = new A();
+''', (CompilationUnit u) {
+        var tlv = u.declarations[0] as TopLevelVariableDeclaration;
+        return tlv.variables.variables[0];
+      });
+    }, throwsStateError);
+  }
+
+  void test_modeLocal_withContext_bad_topLevelVariable_initializer() {
+    expect(() {
+      _resolveTypeModeLocal(
+          r'''
+var v = new A();
+''', (CompilationUnit u) {
+        var tlv = u.declarations[0] as TopLevelVariableDeclaration;
+        return tlv.variables.variables[0].initializer;
+      });
+    }, throwsStateError);
+  }
+
+  void test_modeLocal_withContext_class() {
+    ClassDeclaration c;
+    _resolveTypeModeLocal(
+        r'''
+class C<T1> {
+  A m<T2>() {
+    T1 v1;
+    T2 v2;
+  }
+}
+''', (CompilationUnit u) {
+      c = u.declarations[0] as ClassDeclaration;
+      return c;
+    });
+    var m = c.members[0] as MethodDeclaration;
+
+    // The return type of "m" is not resolved.
+    expect(m.returnType.type, isNull);
+
+    var mb = m.body as BlockFunctionBody;
+    var ms = mb.block.statements;
+
+    // The type of "v1" is resolved.
+    {
+      var vd = ms[0] as VariableDeclarationStatement;
+      expect(vd.variables.type.type.toString(), 'T1');
+    }
+
+    // The type of "v2" is resolved.
+    {
+      var vd = ms[1] as VariableDeclarationStatement;
+      expect(vd.variables.type.type.toString(), 'T2');
+    }
+  }
+
+  void test_modeLocal_withContext_inClass_constructor() {
+    ConstructorDeclaration cc;
+    _resolveTypeModeLocal(
+        r'''
+class C<T> {
+  C() {
+    T v1;
+  }
+}
+''', (CompilationUnit u) {
+      var c = u.declarations[0] as ClassDeclaration;
+      cc = c.members[0] as ConstructorDeclaration;
+      return cc;
+    });
+
+    var ccb = cc.body as BlockFunctionBody;
+    var ccs = ccb.block.statements;
+
+    // The type of "v" is resolved.
+    {
+      var vd = ccs[0] as VariableDeclarationStatement;
+      expect(vd.variables.type.type.toString(), 'T');
+    }
+  }
+
+  void test_modeLocal_withContext_inClass_method() {
+    MethodDeclaration m;
+    _resolveTypeModeLocal(
+        r'''
+class C<T1> {
+  A m<T2>() {
+    T1 v1;
+    T2 v2;
+  }
+}
+''', (CompilationUnit u) {
+      var c = u.declarations[0] as ClassDeclaration;
+      m = c.members[0] as MethodDeclaration;
+      return m;
+    });
+
+    // The return type of "m" is not resolved.
+    expect(m.returnType.type, isNull);
+
+    var mb = m.body as BlockFunctionBody;
+    var ms = mb.block.statements;
+
+    // The type of "v1" is resolved.
+    {
+      var vd = ms[0] as VariableDeclarationStatement;
+      expect(vd.variables.type.type.toString(), 'T1');
+    }
+
+    // The type of "v2" is resolved.
+    {
+      var vd = ms[1] as VariableDeclarationStatement;
+      expect(vd.variables.type.type.toString(), 'T2');
+    }
+  }
+
+  void test_modeLocal_withContext_topLevelFunction() {
+    FunctionDeclaration f;
+    _resolveTypeModeLocal(
+        r'''
+A m<T>() {
+  T v;
+}
+''', (CompilationUnit u) {
+      f = u.declarations[0] as FunctionDeclaration;
+      return f;
+    });
+
+    // The return type of "f" is not resolved.
+    expect(f.returnType.type, isNull);
+
+    var fb = f.functionExpression.body as BlockFunctionBody;
+    var fs = fb.block.statements;
+
+    // The type of "v" is resolved.
+    var vd = fs[0] as VariableDeclarationStatement;
+    expect(vd.variables.type.type.toString(), 'T');
+  }
+
+  void test_modeLocal_withContext_topLevelVariable() {
+    TopLevelVariableDeclaration v;
+    _resolveTypeModeLocal(
+        r'''
+A v = new A();
+''', (CompilationUnit u) {
+      v = u.declarations[0] as TopLevelVariableDeclaration;
+      return v;
+    });
+
+    // The type of "v" is not resolved.
+    expect(v.variables.type.type, isNull);
+
+    // The type of "v" initializer is resolved.
+    var vi = v.variables.variables[0].initializer as InstanceCreationExpression;
+    expect(vi.constructorName.type.type.toString(), 'A');
+  }
+
   void test_visitCatchClause_exception() {
     // catch (e)
     CatchClause clause = AstFactory.catchClause("e");
@@ -3413,6 +3573,48 @@ A get G => new A();
     }
     node.accept(_visitor);
   }
+
+  /**
+   * Parse the given [code], build elements and resolve in the
+   * [TypeResolverMode.local] mode. The [code] is allowed to use only the type
+   * named `A`.
+   */
+  void _resolveTypeModeLocal(
+      String code, AstNode getNodeToResolve(CompilationUnit unit)) {
+    CompilationUnit unit =
+        ParserTestCase.parseCompilationUnit2(code, parseGenericMethods: true);
+    var unitElement = new CompilationUnitElementImpl('/test.dart');
+
+    // Build API elements.
+    {
+      var holder = new ElementHolder();
+      unit.accept(new ElementBuilder(holder, unitElement));
+    }
+
+    // Prepare for resolution.
+    LibraryScope libraryScope;
+    TypeResolverVisitor visitor;
+    {
+      MemoryResourceProvider resourceProvider = new MemoryResourceProvider();
+      InternalAnalysisContext context = AnalysisContextFactory.contextWithCore(
+          resourceProvider: resourceProvider);
+      var source = resourceProvider.getFile('/test.dart').createSource();
+      var libraryElement = new LibraryElementImpl.forNode(context, null)
+        ..definingCompilationUnit = unitElement;
+      libraryScope = new LibraryScope(libraryElement);
+      visitor = new TypeResolverVisitor(
+          libraryElement, source, _typeProvider, _listener,
+          nameScope: libraryScope, mode: TypeResolverMode.local);
+    }
+
+    // Define top-level types.
+    ClassElementImpl A = ElementFactory.classElement2('A');
+    libraryScope.define(A);
+
+    // Perform resolution.
+    AstNode nodeToResolve = getNodeToResolve(unit);
+    nodeToResolve.accept(visitor);
+  }
 }
 
 class _RootScope extends Scope {