Merging r314733:
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r314733 | rsmith | 2017-10-02 15:43:36 -0700 (Mon, 02 Oct 2017) | 5 lines
PR33839: Fix -Wunused handling for structured binding declarations.
We warn about a structured binding declaration being unused only if none of its
bindings are used.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_50@319847
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