Test ResolutionImpact equivalence.

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, 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 dart2js.compiler_base;
 
 import 'dart:async' show
     EventSink,
     Future;
 
@@ skipping 1942 matching lines @@
     }
   }
 }
 
 // TODO(johnniwinther): Move [ResolverTask] here.
 class _CompilerResolution implements Resolution {
   final Compiler compiler;
   final Map<Element, ResolutionImpact> _resolutionImpactCache =
       <Element, ResolutionImpact>{};
   final Map<Element, WorldImpact> _worldImpactCache = <Element, WorldImpact>{};
+  bool retainCaches = false;
 
   _CompilerResolution(this.compiler);
 
   @override
   DiagnosticReporter get reporter => compiler.reporter;
 
   @override
   Parsing get parsing => compiler.parsing;
 
   @override
@@ skipping 23 matching lines @@
   FunctionSignature resolveSignature(FunctionElement function) {
     return compiler.resolver.resolveSignature(function);
   }
 
   @override
   DartType resolveTypeAnnotation(Element element, TypeAnnotation node) {
     return compiler.resolver.resolveTypeAnnotation(element, node);
   }
 
   @override
+  bool hasResolutionImpact(Element element) {
+    return _resolutionImpactCache.containsKey(element);
+  }
+
+  @override
   ResolutionImpact getResolutionImpact(Element element) {
     ResolutionImpact resolutionImpact = _resolutionImpactCache[element];
     assert(invariant(element, resolutionImpact != null,
         message: "ResolutionImpact not available for $element."));
     return resolutionImpact;
   }
 
   @override
   WorldImpact getWorldImpact(Element element) {
     WorldImpact worldImpact = _worldImpactCache[element];
     assert(invariant(element, worldImpact != null,
         message: "WorldImpact not computed for $element."));
     return worldImpact;
   }
 
   @override
   WorldImpact computeWorldImpact(Element element) {
     return _worldImpactCache.putIfAbsent(element, () {
       assert(compiler.parser != null);
       Node tree = compiler.parser.parse(element);
       assert(invariant(element, !element.isSynthesized || tree == null));
       ResolutionImpact resolutionImpact =
           compiler.resolver.resolve(element);
-      if (compiler.serialization.supportSerialization) {
+      if (compiler.serialization.supportSerialization || retainCaches) {
         // [ResolutionImpact] is currently only used by serialization. The
         // enqueuer uses the [WorldImpact] which is always cached.
         // TODO(johnniwinther): Align these use cases better; maybe only
         // cache [ResolutionImpact] and let the enqueuer transform it into
         // a [WorldImpact].
         _resolutionImpactCache[element] = resolutionImpact;
       }
       if (tree != null && !compiler.options.analyzeSignaturesOnly) {
         // TODO(het): don't do this if suppressWarnings is on, currently we have
         // to do it because the typechecker also sets types
         // Only analyze nodes with a corresponding [TreeElements].
         compiler.checker.check(element);
       }
       WorldImpact worldImpact =
           compiler.backend.impactTransformer.transformResolutionImpact(
               resolutionImpact);
       return worldImpact;
     });
   }
 
   @override
   void uncacheWorldImpact(Element element) {
+    if (retainCaches) return;
     if (compiler.serialization.isDeserialized(element)) return;
     assert(invariant(element, _worldImpactCache[element] != null,
         message: "WorldImpact not computed for $element."));
     _worldImpactCache[element] = const WorldImpact();
     _resolutionImpactCache.remove(element);
   }
 
   @override
   void emptyCache() {
+    if (retainCaches) return;
     for (Element element in _worldImpactCache.keys) {
       _worldImpactCache[element] = const WorldImpact();
     }
     _resolutionImpactCache.clear();
   }
 
   @override
   bool hasBeenResolved(Element element) {
     return _worldImpactCache.containsKey(element);
   }
@@ skipping 86 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }