Merge pull request #450 from EliaCereda/sr-197

[SR-197] Skip generic specialization when generic is <<error type>>

Author: lattner

lib/Sema/TypeCheckType.cpp

@@ -367,8 +367,10 @@ Type TypeChecker::applyGenericArguments(Type type,
   if (!unbound) {
     // FIXME: Highlight generic arguments and introduce a Fix-It to remove
     // them.
-    diagnose(loc, diag::not_a_generic_type, type);
-
+    if (!type->is<ErrorType>()) {
+      diagnose(loc, diag::not_a_generic_type, type);
+    }
+    
     // Just return the type; this provides better recovery anyway.
     return type;
   }

test/IDE/print_ast_tc_decls_errors.swift

@@ -168,6 +168,9 @@ typealias Typealias1 = FooNonExistentProtocol // expected-error {{use of undecla
 // NO-TYREPR: {{^}}typealias Typealias1 = <<error type>>{{$}}
 // TYREPR: {{^}}typealias Typealias1 = FooNonExistentProtocol{{$}}
 
+// sr-197
+func foo(bar: Typealias1<Int>) {} // Should not generate error "cannot specialize non-generic type '<<error type>>'"
+
 // Associated types.
 
 protocol AssociatedType1 {