Fix type checking of void type.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
===================================================================
--- runtime/vm/flow_graph_compiler_x64.cc	(revision 9680)
+++ runtime/vm/flow_graph_compiler_x64.cc	(working copy)
@@ -421,6 +421,11 @@
     const AbstractType& type,
     Label* is_instance_lbl,
     Label* is_not_instance_lbl) {
+  if (type.IsVoidType()) {
+    // A non-null value is returned from a void function, which will result in a
+    // type error. A null value is handled prior to executing this inline code.
+    return SubtypeTestCache::null();
+  }
   if (type.IsInstantiated()) {
     const Class& type_class = Class::ZoneHandle(type.type_class());
     // A Smi object cannot be the instance of a parameterized class.
@@ -433,26 +438,23 @@
                                                        is_instance_lbl,
                                                        is_not_instance_lbl);
       // Fall through to runtime call.
-    } else {
-      GenerateInstantiatedTypeNoArgumentsTest(cid,
-                                              token_pos,
-                                              type,
-                                              is_instance_lbl,
-                                              is_not_instance_lbl);
-      // If test non-conclusive so far, try the inlined type-test cache.
-      // 'type' is known at compile time.
-      return GenerateSubtype1TestCacheLookup(
-          cid, token_pos, type_class,
-          is_instance_lbl, is_not_instance_lbl);
     }
-  } else {
-    return GenerateUninstantiatedTypeTest(cid,
-                                          token_pos,
-                                          type,
-                                          is_instance_lbl,
-                                          is_not_instance_lbl);
+    GenerateInstantiatedTypeNoArgumentsTest(cid,
+                                            token_pos,
+                                            type,
+                                            is_instance_lbl,
+                                            is_not_instance_lbl);
+    // If test non-conclusive so far, try the inlined type-test cache.
+    // 'type' is known at compile time.
+    return GenerateSubtype1TestCacheLookup(
+        cid, token_pos, type_class,
+        is_instance_lbl, is_not_instance_lbl);
   }
-  return SubtypeTestCache::null();
+  return GenerateUninstantiatedTypeTest(cid,
+                                        token_pos,
+                                        type,
+                                        is_instance_lbl,
+                                        is_not_instance_lbl);
 }
 
 
@@ -561,7 +563,6 @@
   // Assignable check is skipped in FlowGraphBuilder, not here.
   ASSERT(dst_type.IsMalformed() ||
          (!dst_type.IsDynamicType() && !dst_type.IsObjectType()));
-  ASSERT(!dst_type.IsVoidType());
   __ pushq(RCX);  // Store instantiator.
   __ pushq(RDX);  // Store instantiator type arguments.
   // A null object is always assignable and is returned as result.