Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -112,6 +112,7 @@
   DeclContext *LookupCtx = nullptr;
   bool isDependent = false;
   bool LookInScope = false;
+  LookupNameKind LookupKind = LookupOrdinaryName;
 
   if (SS.isInvalid())
     return nullptr;
@@ -144,7 +145,9 @@
       LookupCtx = DC;
       isDependent = false;
     } else if (DC && isa<CXXRecordDecl>(DC)) {
-      LookAtPrefix = false;
+      // Penultimate name is a class-name, we will LookAtPrefix. However, look
+      // up class-name's in the same scope as the first.
+      LookupKind = LookupNestedNameSpecifierName;
       LookInScope = true;
     }
 
@@ -184,7 +187,7 @@
   }
 
   TypeDecl *NonMatchingTypeDecl = nullptr;
-  LookupResult Found(*this, &II, NameLoc, LookupOrdinaryName);
+  LookupResult Found(*this, &II, NameLoc, LookupKind);
   for (unsigned Step = 0; Step != 2; ++Step) {
     // Look for the name first in the computed lookup context (if we
     // have one) and, if that fails to find a match, in the scope (if
Index: test/CXX/drs/dr2xx.cpp
===================================================================
--- test/CXX/drs/dr2xx.cpp
+++ test/CXX/drs/dr2xx.cpp
@@ -502,7 +502,7 @@
     f.N::F::~E();
     // This is valid; we look up the second F in the same scope in which we
     // found the first one, that is, 'N::'.
-    f.N::F::~F(); // FIXME: expected-error {{expected the class name after '~' to name a destructor}}
+    f.N::F::~F();
     // This is technically ill-formed; G is looked up in 'N::' and is not found;
     // as above, this is probably a bug in the standard.
     f.N::F::~G();
Index: test/SemaCXX/destructor.cpp
===================================================================
--- test/SemaCXX/destructor.cpp
+++ test/SemaCXX/destructor.cpp
@@ -493,4 +493,23 @@
   x.foo1();
 }
 }
+
+namespace PR12350 {
+  class basic_string {
+  public:
+    ~basic_string();
+    char *something;
+  };
+
+  namespace notstd {
+    typedef basic_string string;
+  }
+
+  void
+  foo(notstd::string *bar)
+  {
+    bar->notstd::string::~string(); // OK
+  }
+}
+
 #endif // BE_THE_HEADER