cps-ir: Support foreign code.

pkg/compiler/lib/src/cps_ir/type_propagation.dart

Index: pkg/compiler/lib/src/cps_ir/type_propagation.dart
diff --git a/pkg/compiler/lib/src/cps_ir/type_propagation.dart b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
index 027a3d67a972c19c2f67004f01160ababc442565..eacc21a82ec523dc77d4a5c6742307eca5a643cf 100644
--- a/pkg/compiler/lib/src/cps_ir/type_propagation.dart
+++ b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
@@ -1055,7 +1055,7 @@ class TypePropagationVisitor implements Visitor {
   }
 
   void visitCreateInstance(CreateInstance node) {
-    setValue(node, nonConstant(typeSystem.exact(node.classElement)));
+    setValue(node, nonConstant(typeSystem.exact(node.classElement.declaration)));
   }
 
   void visitReifyRuntimeType(ReifyRuntimeType node) {
@@ -1079,6 +1079,17 @@ class TypePropagationVisitor implements Visitor {
     // TODO(asgerf): Expose [Invocation] type.
     setValue(node, nonConstant(typeSystem.nonNullType));
   }
+
+  @override
+  visitForeignCode(ForeignCode node) {
+    Continuation continuation = node.continuation.definition;
+    setReachable(continuation);
+
+    assert(continuation.parameters.length == 1);
+    Parameter returnValue = continuation.parameters.first;
+
+    setValue(returnValue, nonConstant(node.type));
+  }
 }
 
 /// Represents the abstract value of a primitive value at some point in the