Sema: Remove an unnecessary call to isInvalid()

This forces the interface type, which we don't want to do here.

Author: slavapestov

lib/Sema/TypeCheckType.cpp

@@ -1406,18 +1406,13 @@ static Type resolveNestedIdentTypeComponent(
 
     // Diagnose a bad conformance reference if we need to.
     if (!options.contains(TypeResolutionFlags::SilenceErrors) &&
-        inferredAssocType && memberType && memberType->hasError()) {
+        inferredAssocType && memberType->hasError()) {
       maybeDiagnoseBadConformanceRef(DC, parentTy, comp->getLoc(),
                                      inferredAssocType);
     }
 
-    // If we found a reference to an associated type or other member type that
-    // was marked invalid, just return ErrorType to silence downstream errors.
-    if (member->isInvalid())
-      return ErrorType::get(ctx);
-
     // At this point, we need to have resolved the type of the member.
-    if (!memberType || memberType->hasError())
+    if (memberType->hasError())
       return memberType;
 
     // If there are generic arguments, apply them now.

test/decl/nested/protocol.swift

@@ -106,8 +106,7 @@ func testLookup(_ x: OuterForUFI.Inner) {
   x.extMethod()
 }
 
-// N.B. Lookup fails here because OuterForUFI.Inner is marked invalid.
 func testLookup<T: OuterForUFI.Inner>(_ x: T) {
-  x.req() // expected-error {{value of type 'T' has no member 'req'}}
-  x.extMethod() // expected-error {{value of type 'T' has no member 'extMethod'}}
+  x.req()
+  x.extMethod()
 }