Fix for issue 27199

pkg/compiler/lib/src/ssa/builder.dart

Index: pkg/compiler/lib/src/ssa/builder.dart
diff --git a/pkg/compiler/lib/src/ssa/builder.dart b/pkg/compiler/lib/src/ssa/builder.dart
index 2dc48955cddbb2f54726f3cec0840c53e869747f..9e6773b4b2dc7662a413a411e9382c72f1b2314c 100644
--- a/pkg/compiler/lib/src/ssa/builder.dart
+++ b/pkg/compiler/lib/src/ssa/builder.dart
@@ -3970,6 +3970,7 @@ class SsaBuilder extends ast.Visitor
   HInstruction analyzeTypeArgument(DartType argument,
       {SourceInformation sourceInformation}) {
     assert(assertTypeInContext(argument));
+    argument = argument.unaliased;
     if (argument.treatAsDynamic) {
       // Represent [dynamic] as [null].
       return graph.addConstantNull(compiler);