C++: base class and default argument for template class

Fix code completion in case:
struct Foo
{
  int bar;
};

template <typename T1 = Foo>
struct Derived : T1 { };

int main()
{
  Derived<> foo;
  foo. // members from Foo are not proposed
  return 0;
}

Task-number: QTCREATORBUG-12605
Change-Id: Ibe35c7b9a161e789057a4518c72390ac52489a3e
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/libs/cplusplus/LookupContext.cpp b/src/libs/cplusplus/LookupContext.cpp
index f8cdf106a0..aae1b25ff1 100644
--- a/src/libs/cplusplus/LookupContext.cpp
+++ b/src/libs/cplusplus/LookupContext.cpp
@@ -1082,9 +1082,9 @@ ClassOrNamespace *ClassOrNamespace::nestedType(const Name *name, ClassOrNamespac
             const unsigned argumentCountOfSpecialization
                     = templateSpecialization->templateParameterCount();
 
+            Subst subst(_control.data());
             if (_factory->expandTemplates()) {
                 Clone cloner(_control.data());
-                Subst subst(_control.data());
                 for (unsigned i = 0; i < argumentCountOfSpecialization; ++i) {
                     const TypenameArgument *tParam
                             = templateSpecialization->templateParameterAt(i)->asTypenameArgument();
@@ -1149,6 +1149,13 @@ ClassOrNamespace *ClassOrNamespace::nestedType(const Name *name, ClassOrNamespac
                             }
                         }
                     }
+                    if (!baseBinding && subst.contains(baseName)) {
+                        const FullySpecifiedType &fullType = subst[baseName];
+                        if (fullType.isValid()) {
+                            if (NamedType *namedType = fullType.type()->asNamedType())
+                                baseBinding = lookupType(namedType->name());
+                        }
+                    }
                 } else {
                     SubstitutionMap map;
                     for (unsigned i = 0;