Fix for Bug 28423 - error: too many arguments to function call, expected single argument '__pq', have 2 arguments void swap(priority_queue __pq)

[CrisCristescu]

Summary

This patch is a fix for the Bug 28423.

The problem was that the context std context to which compared against was not the primary context.

[rsmith]

lib/Sema/SemaExceptionSpec.cpp

47

Just change this to

`!RD || !getStdNamespace() || !RD->getEnclosingNamespaceContext().Equals(getStdNamespace())`

[CrisCristescu]

Updated the fix as suggested.

[rsmith]

Code change looks OK, but can you reduce the testcase some more? Something like

namespace std {
  template<typename T> void swap(T, T);
  template<typename T> struct array {
    T t;
    void swap(array) noexcept(noexcept(swap(t, t)));
  };
}

... as a header and ...

void f(std::array<int> ai) { ai.swap(ai); }

... as a test seems like they should be enough, once you create the situation that Sema's StdNamespace is not the primary context for the std namespace.

[v.g.vassilev]

Landed in r279371.

lib/Sema/SemaExceptionSpec.cpp

 /// swap function then tries to call std::swap unqualified from the exception
 /// specification of that function. This function detects whether we're in
 /// such a case and turns off delay-parsing of exception specifications.
 bool Sema::isLibstdcxxEagerExceptionSpecHack(const Declarator &D) {
   auto *RD = dyn_cast<CXXRecordDecl>(CurContext);
 
   // All the problem cases are member functions named "swap" within class
   // templates declared directly within namespace std.
-  if (!RD || RD->getEnclosingNamespaceContext() != getStdNamespace() ||
+  if (!RD || !getStdNamespace() ||
+      !RD->getEnclosingNamespaceContext()->Equals(getStdNamespace()) ||
       !RD->getIdentifier() || !RD->getDescribedClassTemplate() ||
       !D.getIdentifier() || !D.getIdentifier()->isStr("swap"))
     return false;
 
   // Only apply this hack within a system header.
   if (!Context.getSourceManager().isInSystemHeader(D.getLocStart()))
     return false;
 

test/Modules/Inputs/PR28423/Allocator.h

+
+#include "SmallVector.h"
+#include "Memory.h"

test/Modules/Inputs/PR28423/Memory.h

+#include <string>

test/Modules/Inputs/PR28423/SmallVector.h

+
+#include "iterator_range.h"
+#include <string>
+namespace std {
+template <typename _Tp, typename = allocator<_Tp>> class vector;
+}
+

test/Modules/Inputs/PR28423/StringMap.h

+#include "StringRef.h"
+#include "Allocator.h"
+#include "iterator_range.h"
+namespace std {}

test/Modules/Inputs/PR28423/StringRef.h

+namespace llvm{}

test/Modules/Inputs/PR28423/iterator_range.h

+namespace llvm {}

test/Modules/Inputs/PR28423/module.modulemap

+module "StringRef.h" {header "StringRef.h" export *}
+module "iterator_range.h" {header "iterator_range.h" export *}
+module "SmallVector.h" {header "SmallVector.h" export *}
+module "StringMap.h" {header "StringMap.h" export *}
+module "Memory.h" {header "Memory.h" export *}
+module "Allocator.h" {header "Allocator.h" export *}

test/Modules/Inputs/PR28423/queue

+#pragma GCC system_header
+namespace std {
+template <typename, typename _Sequence,
+          typename _Compare = less<typename _Sequence::value_type>>
+class priority_queue {
+  _Compare comp;
+
+public:
+  void swap(priority_queue __pq) noexcept(noexcept(swap(comp, comp)));
+};
+}

test/Modules/Inputs/PR28423/string

+#ifndef _GLIBCXX_STRING
+#define _GLIBCXX_STRING
+namespace std {
+template <typename _Tp> void swap(_Tp, _Tp);
+template <typename> class allocator;
+template <typename> struct greater {};
+template <typename> struct less;
+}
+#endif

test/Modules/pr28423.cpp

+// RUN: rm -rf %t
+// RUN: %clang_cc1 -std=c++11 -I%S/Inputs/PR28423 -verify %s
+// RUN: %clang_cc1 -std=c++11 -fmodules -fmodule-map-file=%S/Inputs/PR28423/module.modulemap -fmodules-cache-path=%t -I%S/Inputs/PR28423/ -verify %s
+
+#include "StringMap.h"
+#include <queue>
+
+std::priority_queue<unsigned, std::vector<unsigned>, std::greater<unsigned>> a,b;
+void fn1() { a.swap(b); }
+
+// expected-no-diagnostics
 No newline at end of file