From 8f491b9cec281d76f02f8f992d8ad19d6d24146d Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron@aaronballman.com>
Date: Tue, 21 Nov 2017 19:22:34 +0000
Subject: [PATCH] Add an AST matcher for hasDefaultArgument() to match on
 parameter declarations that have a default value.

Patch by Julie Hockett.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@318794 91177308-0d34-0410-b5e6-96231b3b80d8
---
 docs/LibASTMatchersReference.html                  |  9 +++++++++
 include/clang/ASTMatchers/ASTMatchers.h            | 11 +++++++++++
 lib/ASTMatchers/Dynamic/Registry.cpp               |  1 +
 unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp |  7 +++++++
 4 files changed, 28 insertions(+)

diff --git a/docs/LibASTMatchersReference.html b/docs/LibASTMatchersReference.html
index 295b0b1e43..e82bc3e5dc 100644
--- a/docs/LibASTMatchersReference.html
+++ b/docs/LibASTMatchersReference.html
@@ -3183,6 +3183,15 @@ Usable as: Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1TagDe
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ParmVarDecl.html">ParmVarDecl</a>&gt;</td><td class="name" onclick="toggle('hasDefaultArgument0')"><a name="hasDefaultArgument0Anchor">hasDefaultArgument</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="hasDefaultArgument0"><pre>Matches a declaration that has default arguments.
+
+Example matches y (matcher = parmVarDecl(hasDefaultArgument()))
+void x(int val) {}
+void y(int val = 0) {}
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1QualType.html">QualType</a>&gt;</td><td class="name" onclick="toggle('asString0')"><a name="asString0Anchor">asString</a></td><td>std::string Name</td></tr>
 <tr><td colspan="4" class="doc" id="asString0"><pre>Matches if the matched type is represented by the given string.
 
diff --git a/include/clang/ASTMatchers/ASTMatchers.h b/include/clang/ASTMatchers/ASTMatchers.h
index 5f5d350ced..1906a57014 100644
--- a/include/clang/ASTMatchers/ASTMatchers.h
+++ b/include/clang/ASTMatchers/ASTMatchers.h
@@ -5817,6 +5817,17 @@ AST_MATCHER(NamedDecl, hasExternalFormalLinkage) {
   return Node.hasExternalFormalLinkage();
 }
 
+/// \brief Matches a declaration that has default arguments.
+///
+/// Example matches y (matcher = parmVarDecl(hasDefaultArgument()))
+/// \code
+/// void x(int val) {}
+/// void y(int val = 0) {}
+/// \endcode
+AST_MATCHER(ParmVarDecl, hasDefaultArgument) { 
+  return Node.hasDefaultArg(); 
+}
+
 } // namespace ast_matchers
 } // namespace clang
 
diff --git a/lib/ASTMatchers/Dynamic/Registry.cpp b/lib/ASTMatchers/Dynamic/Registry.cpp
index be2e1b77ee..27891b8e6a 100644
--- a/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -248,6 +248,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(hasDeclaration);
   REGISTER_MATCHER(hasDeclContext);
   REGISTER_MATCHER(hasDeducedType);
+  REGISTER_MATCHER(hasDefaultArgument);
   REGISTER_MATCHER(hasDescendant);
   REGISTER_MATCHER(hasDestinationType);
   REGISTER_MATCHER(hasDynamicExceptionSpec);
diff --git a/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
index 3858384e55..9c9304a6f8 100644
--- a/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ b/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -1991,5 +1991,12 @@ TEST(HasExternalFormalLinkage, Basic) {
                       namedDecl(hasExternalFormalLinkage())));
 }
 
+TEST(HasDefaultArgument, Basic) {
+  EXPECT_TRUE(matches("void x(int val = 0) {}", 
+                      parmVarDecl(hasDefaultArgument())));
+  EXPECT_TRUE(notMatches("void x(int val) {}",
+                      parmVarDecl(hasDefaultArgument())));
+}
+
 } // namespace ast_matchers
 } // namespace clang
-- 
2.50.1