Improve diagnostics if friend function redefines file-level function.
Clang makes check for function redefinition after it merged the new
declaration with the existing one. As a result, it produces poor
diagnostics in the case of a friend function defined inline, as in
the code:
```
void func() {}
class C { friend void func() {} };
```
Error message in this case states that `inline declaration of 'func'
follows non-inline definition`, which is misleading, as `func` does
not have explicit `inline` specifier.
With this changes compiler reports function redefinition if the new
function is a friend defined inline and it does not have explicit
`inline` specifier.
Differential Revision: https://reviews.llvm.org/D26065
llvm-svn: 304964
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 3e23063..313552e 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -638,7 +638,12 @@
Diag(Old->getLocation(), diag::note_previous_declaration);
Invalid = true;
} else if (!Old->getMostRecentDecl()->isInlined() && New->isInlined() &&
- Old->isDefined(Def)) {
+ Old->isDefined(Def) &&
+ // If a friend function is inlined but does not have 'inline'
+ // specifier, it is a definition. Do not report attribute conflict
+ // in this case, redefinition will be diagnosed later.
+ (New->isInlineSpecified() ||
+ New->getFriendObjectKind() == Decl::FOK_None)) {
// C++11 [dcl.fcn.spec]p4:
// If the definition of a function appears in a translation unit before its
// first declaration as inline, the program is ill-formed.