[PATCH] D20519: [clang-tidy] Ignore ADL-style using decls in unused-using-decls check.

[Alexander Kornienko via cfe-commits]

alexfh requested changes to this revision.
This revision now requires changes to proceed.

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Comment at: clang-tidy/misc/UnusedUsingDeclsCheck.cpp:47
@@ +46,3 @@
+      return;
+    // Ignores using-declarations defined in function definitions to avoid
+    // arguement-dependent lookup.
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hokein wrote:
> alexfh wrote:
> > I don't think using declarations in functions are inherently related to ADL. This check doesn't seem like a useful heuristic.
> Yeah, the current work around is only to ignore all using-decls in function context which is not perfect. I didn't find out a better way.
If we're talking about this pattern:

  using std::swap;
  ...
  ::ns::T x, y;
  swap(x, y); // ::ns::swap() is used

then for each function name resolved using ADL, we can find all using declarations for the same name in different namespaces and mark them used. WDYT?


http://reviews.llvm.org/D20519