Add token invariant to DiagnosticReporter

Closes #3675

[email protected]

Review URL: https://codereview.chromium.org/1520293002.

Author: johnniwinther

pkg/compiler/lib/src/compiler.dart

@@ -1792,6 +1792,67 @@ class _CompilerDiagnosticReporter extends DiagnosticReporter {
     }
     if (uri == null && currentElement != null) {
       uri = currentElement.compilationUnit.script.resourceUri;
+      assert(invariant(currentElement, () {
+
+        /// Check that [begin] and [end] can be found between [from] and [to].
+        validateToken(Token from, Token to) {
+          if (from == null || to == null) return true;
+          bool foundBegin = false;
+          bool foundEnd = false;
+          Token token = from;
+          while (true) {
+            if (token == begin) {
+              foundBegin = true;
+            }
+            if (token == end) {
+              foundEnd = true;
+            }
+            if (foundBegin && foundEnd) {
+              return true;
+            }
+            if (token == to || token == token.next || token.next == null) {
+              break;
+            }
+            token = token.next;
+          }
+
+          // Create a good message for when the tokens were not found.
+          StringBuffer sb = new StringBuffer();
+          sb.write('Invalid current element: $currentElement. ');
+          sb.write('Looking for ');
+          sb.write('[${begin} (${begin.hashCode}),');
+          sb.write('${end} (${end.hashCode})] in');
+
+          token = from;
+          while (true) {
+            sb.write('\n ${token} (${token.hashCode})');
+            if (token == to || token == token.next || token.next == null) {
+              break;
+            }
+            token = token.next;
+          }
+          return sb.toString();
+        }
+
+        if (currentElement.enclosingClass != null &&
+            currentElement.enclosingClass.isEnumClass) {
+          // Enums ASTs are synthesized (and give messed up messages).
+          return true;
+        }
+
+        if (currentElement is AstElement) {
+          AstElement astElement = currentElement;
+          if (astElement.hasNode) {
+            Token from = astElement.node.getBeginToken();
+            Token to = astElement.node.getEndToken();
+            if (astElement.metadata.isNotEmpty) {
+              from = astElement.metadata.first.beginToken;
+            }
+            return validateToken(from, to);
+          }
+        }
+        return true;
+      }, message: "Invalid current element: $currentElement [$begin,$end]."));
     }
     return new SourceSpan.fromTokens(uri, begin, end);
   }

pkg/compiler/lib/src/diagnostics/diagnostic_listener.dart

@@ -69,6 +69,11 @@ abstract class DiagnosticReporter {
 
   internalError(Spannable spannable, message);
 
+  /// Creates a [SourceSpan] for [node] in scope of the current element.
+  ///
+  /// If [node] is a [Node] or [Token] we assert in checked mode that the
+  /// corresponding tokens can be found within the tokens of the current
+  /// element.
   SourceSpan spanFromSpannable(Spannable node);
 
   void reportErrorMessage(
@@ -109,10 +114,8 @@ abstract class DiagnosticReporter {
   void reportInfo(Spannable node, MessageKind errorCode,
                   [Map arguments = const {}]);
 
-  // TODO(ahe): We should not expose this here.  Perhaps a
-  // [SourceSpan] should implement [Spannable], and we should have a
-  // way to construct a [SourceSpan] from a [Spannable] and an
-  // [Element].
+  /// Set current element of this reporter to [element]. This is used for
+  /// creating [SourceSpan] in [spanFromSpannable].
   withCurrentElement(Element element, f());
 
   DiagnosticMessage createMessage(

pkg/compiler/lib/src/diagnostics/invariant.dart

@@ -48,6 +48,10 @@ bool invariant(Spannable spannable, var condition, {var message: null}) {
   }
   if (condition is Function){
     condition = condition();
+    if (condition is String) {
+      message = condition;
+      condition = false;
+    }
   }
   if (!condition) {
     if (message is Function) {

pkg/compiler/lib/src/resolution/constructors.dart

@@ -66,7 +66,9 @@ class InitializerResolver {
     return node.receiver.asIdentifier().isThis();
   }
 
-  reportDuplicateInitializerError(Element field, Node init, Node existing) {
+  reportDuplicateInitializerError(Element field,
+                                  Node init,
+                                  Spannable existing) {
     reporter.reportError(
         reporter.createMessage(
             init,
@@ -90,7 +92,9 @@ class InitializerResolver {
       field.parseNode(visitor.resolution.parsing);
       Expression initializer = field.initializer;
       if (initializer != null) {
-        reportDuplicateInitializerError(field, init, initializer);
+        reportDuplicateInitializerError(field, init,
+            reporter.withCurrentElement(field,
+                () => reporter.spanFromSpannable(initializer)));
       }
     }
     initialized[field] = init;

pkg/compiler/lib/src/resolution/enum_creator.dart

@@ -180,6 +180,8 @@ class AstBuilder {
   }
 }
 
+// TODO(johnniwinther): Avoid creating synthesized ASTs for enums when SSA is
+// removed.
 class EnumCreator {
   final DiagnosticReporter reporter;
   final CoreTypes coreTypes;

pkg/compiler/lib/src/resolution/members.dart

@@ -802,7 +802,7 @@ class ResolverVisitor extends MappingVisitor<ResolutionResult> {
       registry.registerFeature(Feature.COMPILE_TIME_ERROR);
       return new StaticAccess.invalid(error);
     }
-    registry.registerSuperUse(node);
+    registry.registerSuperUse(reporter.spanFromSpannable(node));
     return null;
   }
 

pkg/compiler/lib/src/resolution/registry.dart

@@ -19,6 +19,7 @@ import '../compiler.dart' show
     Compiler;
 import '../constants/expressions.dart';
 import '../dart_types.dart';
+import '../diagnostics/source_span.dart';
 import '../enqueue.dart' show
     ResolutionEnqueuer;
 import '../elements/elements.dart';
@@ -314,8 +315,8 @@ class ResolutionRegistry extends Registry {
     worldImpact.registerTypeUse(typeUse);
   }
 
-  void registerSuperUse(Node node) {
-    mapping.addSuperUse(node);
+  void registerSuperUse(SourceSpan span) {
+    mapping.addSuperUse(span);
   }
 
   void registerTypeLiteral(Send node, DartType type) {

pkg/compiler/lib/src/resolution/resolution.dart

@@ -513,7 +513,7 @@ class ResolverTask extends CompilerTask {
    * called by [resolveClass] and [ClassSupertypeResolver].
    */
   void loadSupertypes(BaseClassElementX cls, Spannable from) {
-    reporter.withCurrentElement(cls, () => measure(() {
+    measure(() {
       if (cls.supertypeLoadState == STATE_DONE) return;
       if (cls.supertypeLoadState == STATE_STARTED) {
         reporter.reportErrorMessage(
@@ -540,7 +540,7 @@ class ResolverTask extends CompilerTask {
           cls.supertypeLoadState = STATE_DONE;
         }
       });
-    }));
+    });
   }
 
   // TODO(johnniwinther): Remove this queue when resolution has been split into
@@ -763,15 +763,15 @@ class ResolverTask extends CompilerTask {
                            ClassElement mixin) {
     // TODO(johnniwinther): Avoid the use of [TreeElements] here.
     if (resolutionTree == null) return;
-    Iterable<Node> superUses = resolutionTree.superUses;
+    Iterable<SourceSpan> superUses = resolutionTree.superUses;
     if (superUses.isEmpty) return;
     DiagnosticMessage error = reporter.createMessage(
         mixinApplication,
         MessageKind.ILLEGAL_MIXIN_WITH_SUPER,
         {'className': mixin.name});
     // Show the user the problematic uses of 'super' in the mixin.
     List<DiagnosticMessage> infos = <DiagnosticMessage>[];
-    for (Node use in superUses) {
+    for (SourceSpan use in superUses) {
       infos.add(reporter.createMessage(
           use,
           MessageKind.ILLEGAL_MIXIN_SUPER_USE));

pkg/compiler/lib/src/resolution/tree_elements.dart

@@ -7,6 +7,7 @@ library dart2js.resolution.tree_elements;
 import '../common.dart';
 import '../constants/expressions.dart';
 import '../dart_types.dart';
+import '../diagnostics/source_span.dart';
 import '../elements/elements.dart';
 import '../types/types.dart' show
     TypeMask;
@@ -22,7 +23,7 @@ import 'send_structure.dart';
 
 abstract class TreeElements {
   AnalyzableElement get analyzedElement;
-  Iterable<Node> get superUses;
+  Iterable<SourceSpan> get superUses;
 
   void forEachConstantNode(f(Node n, ConstantExpression c));
 
@@ -111,7 +112,7 @@ class TreeElementMapping extends TreeElements {
   Map<Spannable, TypeMask> _typeMasks;
   Map<Node, DartType> _types;
   Map<Node, DartType> typesCache = <Node, DartType>{};
-  Setlet<Node> _superUses;
+  Setlet<SourceSpan> _superUses;
   Map<Node, ConstantExpression> _constants;
   Map<VariableElement, List<Node>> _potentiallyMutated;
   Map<Node, Map<VariableElement, List<Node>>> _potentiallyMutatedIn;
@@ -191,15 +192,15 @@ class TreeElementMapping extends TreeElements {
 
   DartType getType(Node node) => _types != null ? _types[node] : null;
 
-  Iterable<Node> get superUses {
-    return _superUses != null ? _superUses : const <Node>[];
+  Iterable<SourceSpan> get superUses {
+    return _superUses != null ? _superUses : const <SourceSpan>[];
   }
 
-  void addSuperUse(Node node) {
+  void addSuperUse(SourceSpan span) {
     if (_superUses == null) {
-      _superUses = new Setlet<Node>();
+      _superUses = new Setlet<SourceSpan>();
     }
-    _superUses.add(node);
+    _superUses.add(span);
   }
 
   Selector _getSelector(Spannable node) {

tests/co19/co19-dart2js.status

@@ -134,7 +134,6 @@ Language/Reference/Lexical_Rules/whitespace_t06: MissingCompileTimeError # Check
 Language/Statements/Local_Function_Declaration/reference_before_declaration_t01: MissingCompileTimeError # Issue 21050
 Language/Statements/Local_Function_Declaration/reference_before_declaration_t03: MissingCompileTimeError # Issue 21050
 Language/Types/Interface_Types/subtype_t27: Skip # Times out or crashes. Issue 21174
-Language/Types/Interface_Types/subtype_t28: crash # Issue 21174
 Language/Types/Interface_Types/subtype_t30: fail # Issue 14654
 Language/Variables/final_t01: fail # Issue 21093
 Language/Variables/final_t02: fail # Issue 21093