Add AccessSemantics.INVALID for invalid expressions.

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

Index: pkg/compiler/lib/src/resolution/access_semantics.dart
diff --git a/pkg/compiler/lib/src/resolution/access_semantics.dart b/pkg/compiler/lib/src/resolution/access_semantics.dart
index 2c741b3454b68287af8f4cc527e0370e25051980..830d40175e87d23eefffc60dc7c34353f1331c96 100644
--- a/pkg/compiler/lib/src/resolution/access_semantics.dart
+++ b/pkg/compiler/lib/src/resolution/access_semantics.dart
@@ -143,6 +143,10 @@ enum AccessKind {
 
   /// The destination of the access is unresolved super access.
   UNRESOLVED_SUPER,
+
+  /// The destination is invalid as an access. For instance a prefix used
+  /// as an expression.
+  INVALID,
 }
 
 enum CompoundAccessKind {
@@ -357,6 +361,9 @@ class StaticAccess extends AccessSemantics {
 
   StaticAccess.unresolvedSuper(this.element)
       : super._(AccessKind.UNRESOLVED_SUPER);
+
+  StaticAccess.invalid(this.element)
+      : super._(AccessKind.INVALID);
 }
 
 class CompoundAccessSemantics extends AccessSemantics {