[kernel] offsets on direct property get/set

pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart

Index: pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart b/pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart
index 4a93680141f02d7e50d4242801668cc6d365f7f8..71f99b8e7045b57c2e0d201938c2f135fab32831 100644
--- a/pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart
@@ -225,23 +225,25 @@ class NullAwarePropertyAccessor extends Accessor {
 class SuperPropertyAccessor extends Accessor {
   Name name;
   Member getter, setter;
+  final int charOffset;
 
-  SuperPropertyAccessor(this.name, this.getter, this.setter);
+  SuperPropertyAccessor(this.name, this.getter, this.setter, this.charOffset);
 
   _makeRead() {
     if (getter == null) return makeInvalidRead();
     // TODO(ahe): Use [DirectPropertyGet] when possible.
-    Expression result = new DirectPropertyGet(new ThisExpression(), getter);
-    result = new SuperPropertyGet(name, getter);
+    Expression result = new DirectPropertyGet(new ThisExpression(), getter)
+      ..fileOffset = charOffset;
+    result = new SuperPropertyGet(name, getter)..fileOffset = charOffset;
     return result;
   }
 
   _makeWrite(Expression value, bool voidContext) {
     if (setter == null) return makeInvalidWrite(value);
     // TODO(ahe): Use [DirectPropertySet] when possible.
-    Expression result =
-        new DirectPropertySet(new ThisExpression(), setter, value);
-    result = new SuperPropertySet(name, value, setter);
+    Expression result = new DirectPropertySet(
+        new ThisExpression(), setter, value)..fileOffset = charOffset;
+    result = new SuperPropertySet(name, value, setter)..fileOffset = charOffset;
     return result;
   }
 }