[NFC] Fixup TypeChecker::getArraySliceType To Not Return Type()

Author: CodaFi

lib/Sema/CSGen.cpp

@@ -2938,7 +2938,7 @@ namespace {
       // Try to build the appropriate type for a variadic argument list of
       // the fresh element type.  If that failed, just bail out.
       auto array = TypeChecker::getArraySliceType(expr->getLoc(), element);
-      if (!array) return element;
+      if (array->hasError()) return element;
 
       // Require the operand to be convertible to the array type.
       CS.addConstraint(ConstraintKind::Conversion,

lib/Sema/TypeCheckDecl.cpp

@@ -2101,7 +2101,7 @@ static Type validateParameterType(ParamDecl *decl) {
 
   if (decl->isVariadic()) {
     Ty = TypeChecker::getArraySliceType(decl->getStartLoc(), Ty);
-    if (Ty.isNull()) {
+    if (Ty->hasError()) {
       decl->setInvalid();
       return ErrorType::get(ctx);
     }

lib/Sema/TypeCheckType.cpp

@@ -364,7 +364,7 @@ Type TypeChecker::getArraySliceType(SourceLoc loc, Type elementType) {
   ASTContext &ctx = elementType->getASTContext();
   if (!ctx.getArrayDecl()) {
     ctx.Diags.diagnose(loc, diag::sugar_type_not_found, 0);
-    return Type();
+    return ErrorType::get(ctx);
   }
 
   return ArraySliceType::get(elementType);