[PATCH] Refactor Matcher<T> and DynTypedMatcher to reduce overhead of casts.

[Manuel Klimek]

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Comment at: include/clang/ASTMatchers/ASTMatchersInternal.h:290-292
@@ +289,5 @@
+  ///
+  /// Different matchers might have the same \c Implementation pointer with a
+  /// different \c RestrictKind, so we need to include both in the ID.
+  /// \c MatcherIDType supports operator< and provides strict weak ordering.
+  typedef std::pair<ast_type_traits::ASTNodeKind, uint64_t> MatcherIDType;
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Can you give an example in the comment? I find it not trivial to reason about the actual cases this affects.

http://reviews.llvm.org/D5485