[clang-doc] Fix unused variable

Differential Revision: https://reviews.llvm.org/D50709

llvm-svn: 339685
diff --git a/clang-tools-extra/clang-doc/Mapper.cpp b/clang-tools-extra/clang-doc/Mapper.cpp
index 6131a35..0b00bd1 100644
--- a/clang-tools-extra/clang-doc/Mapper.cpp
+++ b/clang-tools-extra/clang-doc/Mapper.cpp
@@ -30,7 +30,7 @@
     return true;
 
   // Skip function-internal decls.
-  if (const DeclContext *F = D->getParentFunctionOrMethod())
+  if (D->getParentFunctionOrMethod())
     return true;
 
   llvm::SmallString<128> USR;