Use READY_RESOLVED_UNIT flag for ordering tasks.

pkg/analyzer/lib/src/task/dart.dart

Index: pkg/analyzer/lib/src/task/dart.dart
diff --git a/pkg/analyzer/lib/src/task/dart.dart b/pkg/analyzer/lib/src/task/dart.dart
index 5a64d4c347eaa7189beff0b93d64ffc5e05fa219..e8c86d35d24dc85be931f182b6f643538d2f5a91 100644
--- a/pkg/analyzer/lib/src/task/dart.dart
+++ b/pkg/analyzer/lib/src/task/dart.dart
@@ -2946,8 +2946,8 @@ class InferInstanceMembersInUnitTask extends SourceBasedAnalysisTask {
       // Require that full inference be complete for all dependencies of the
       // current library cycle.
       'orderLibraryCycles': LIBRARY_CYCLE_DEPENDENCIES.of(unit).toList(
-          (CompilationUnitElementImpl unit) => RESOLVED_UNIT9
-              .of(new LibrarySpecificUnit(unit.librarySource, unit.source)))
+          (CompilationUnitElementImpl unit) =>
+              READY_RESOLVED_UNIT.of(unit.librarySource))

[Brian Wilkerson, 2015/12/18 18:52:19]

I'm a little concerned by the specifics of this change. I like the general idea
a lot, but I'm concerned because READY_RESOLVED_UNIT implies a lot more analysis
(such as constant evaluation) than RESOLVED_UNIT9 did. Even assuming that we can
safely perform that extra analysis at this point without creating a cycle in the
dependency graph (which I haven't convinced myself of), I'd like to (a) do less
work rather than more and (b) remember the real dependencies so that it's clear
in the future what can and cannot change in terms of the task structure.

Perhaps we could define a result (named something like CREATED_RESOLVED_UNIT9)
that gets created by the same task that creates RESOLVED_UNIT9, and then we
could depend on that flag here. The flag would have the semantics that we know
that the work of creating a RESOLVED_UNIT9 had been done, whether the result was
still in the cache or not.

     };
   }
 
@@ -3186,8 +3186,8 @@ class InferStaticVariableTypeTask extends InferStaticVariableTask {
       // Require that full inference be complete for all dependencies of the
       // current library cycle.
       'orderLibraryCycles': LIBRARY_CYCLE_DEPENDENCIES.of(unit).toList(
-          (CompilationUnitElementImpl unit) => RESOLVED_UNIT9
-              .of(new LibrarySpecificUnit(unit.librarySource, unit.source)))
+          (CompilationUnitElementImpl unit) =>
+              READY_RESOLVED_UNIT.of(unit.librarySource))
     };
   }
 
@@ -3654,8 +3654,8 @@ class PartiallyResolveUnitReferencesTask extends SourceBasedAnalysisTask {
       // Require that full inference be complete for all dependencies of the
       // current library cycle.
       'orderLibraryCycles': LIBRARY_CYCLE_DEPENDENCIES.of(unit).toList(
-          (CompilationUnitElementImpl unit) => RESOLVED_UNIT9
-              .of(new LibrarySpecificUnit(unit.librarySource, unit.source)))
+          (CompilationUnitElementImpl unit) =>
+              READY_RESOLVED_UNIT.of(unit.librarySource))
     };
   }
 
@@ -4439,8 +4439,8 @@ class ResolveInstanceFieldsInUnitTask extends SourceBasedAnalysisTask {
       // Require that full inference be complete for all dependencies of the
       // current library cycle.
       'orderLibraryCycles': LIBRARY_CYCLE_DEPENDENCIES.of(unit).toList(
-          (CompilationUnitElementImpl unit) => RESOLVED_UNIT9
-              .of(new LibrarySpecificUnit(unit.librarySource, unit.source)))
+          (CompilationUnitElementImpl unit) =>
+              READY_RESOLVED_UNIT.of(unit.librarySource))
     };
   }
 
@@ -5101,7 +5101,6 @@ class StrongModeVerifyUnitTask extends SourceBasedAnalysisTask {
       unit.accept(new CodeChecker(
           typeProvider, new StrongTypeSystemImpl(), errorListener));
     }
-
     //
     // Record outputs.
     //