[kernel] set dartAsyncMarker to Sync for continuations

pkg/kernel/lib/transformations/continuation.dart

Index: pkg/kernel/lib/transformations/continuation.dart
diff --git a/pkg/kernel/lib/transformations/continuation.dart b/pkg/kernel/lib/transformations/continuation.dart
index a8b28205e7d446a47eaba6eb9ee6be33d804d52d..e849a4d19f355f18d2ae738967f2fd61f2b5da88 100644
--- a/pkg/kernel/lib/transformations/continuation.dart
+++ b/pkg/kernel/lib/transformations/continuation.dart
@@ -128,7 +128,8 @@ class SyncStarFunctionRewriter extends ContinuationRewriterBase {
     final function = new FunctionNode(buildClosureBody(),
         positionalParameters: [iteratorVariable],
         requiredParameterCount: 1,
-        asyncMarker: AsyncMarker.SyncYielding)
+        asyncMarker: AsyncMarker.SyncYielding,
+        dartAsyncMarker: AsyncMarker.Sync)

[Kevin Millikin (Google), 2017/03/13 11:20:35]

This is a fresh function that doesn't correspond directly to any Dart function,
so thinking about its async marker is weird.

We need a comment here explaining why we chose sync and what the consequences
are.  You could say: "SyncYielding functions have no Dart equivalent.  Since
they are synchronous, we use Sync.  (The Dart VM backend uses the Dart async
marker to decide if functions are debuggable.)

Really, this suggests to me that we should consider bringing back is_debuggable
as a separate bit on functions, if we want to hide some but not all of them from
the debugger.

       ..fileOffset = enclosingFunction.fileOffset
       ..fileEndOffset = enclosingFunction.fileEndOffset
       ..returnType = helper.coreTypes.boolClass.rawType;
@@ -226,7 +227,8 @@ abstract class AsyncRewriterBase extends ContinuationRewriterBase {
     final function = new FunctionNode(buildWrappedBody(),
         positionalParameters: parameters,
         requiredParameterCount: 0,
-        asyncMarker: AsyncMarker.SyncYielding)
+        asyncMarker: AsyncMarker.SyncYielding,
+        dartAsyncMarker: AsyncMarker.Sync)
       ..fileOffset = enclosingFunction.fileOffset
       ..fileEndOffset = enclosingFunction.fileEndOffset;