Add cxxStdInitializerListExpr AST matcher

Summary:
This adds a new ASTMatcher for CXXStdInitializerListExprs that matches C++ initializer list expressions.

The primary motivation is to use it to fix [[ https://bugs.llvm.org/show_bug.cgi?id=32896 | PR32896 ]] (review here [[ https://reviews.llvm.org/D32767 | D32767 ]]).

Reviewers: alexfh, Prazek, aaron.ballman

Reviewed By: alexfh, aaron.ballman

Subscribers: malcolm.parsons, cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D32810

llvm-svn: 302287

clang/docs/LibASTMatchersReference.html

@@ -924,6 +924,19 @@ in
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('cxxStdInitializerListExpr0')"><a name="cxxStdInitializerListExpr0Anchor">cxxStdInitializerListExpr</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXStdInitializerListExpr.html">CXXStdInitializerListExpr</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="cxxStdInitializerListExpr0"><pre>Matches C++ initializer list expressions.
+
+Given
+  std::vector&lt;int&gt; a({ 1, 2, 3 });
+  std::vector&lt;int&gt; b = { 4, 5 };
+  int c[] = { 6, 7 };
+  std::pair&lt;int, int&gt; d = { 8, 9 };
+cxxStdInitializerListExpr()
+  matches "{ 1, 2, 3 }" and "{ 4, 5 }"
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('cxxTemporaryObjectExpr0')"><a name="cxxTemporaryObjectExpr0Anchor">cxxTemporaryObjectExpr</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXTemporaryObjectExpr.html">CXXTemporaryObjectExpr</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="cxxTemporaryObjectExpr0"><pre>Matches functional cast expressions having N != 1 arguments
 
@@ -1160,7 +1173,7 @@ Example matches [&amp;](){return 5;}
 <tr><td colspan="4" class="doc" id="materializeTemporaryExpr0"><pre>Matches nodes where temporaries are materialized.
 
 Example: Given
-  struct T {void func()};
+  struct T {void func();};
   T f();
   void g(T);
 materializeTemporaryExpr() matches 'f()' in these statements
@@ -5233,7 +5246,7 @@ Example matches y in x(y)
 <tr><td colspan="4" class="doc" id="hasReceiverType0"><pre>Matches on the receiver of an ObjectiveC Message expression.
 
 Example
-matcher = objCMessageExpr(hasRecieverType(asString("UIWebView *")));
+matcher = objCMessageExpr(hasReceiverType(asString("UIWebView *")));
 matches the [webView ...] message invocation.
   NSString *webViewJavaScript = ...
   UIWebView *webView = ...

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -1223,6 +1223,20 @@ AST_MATCHER_P(InitListExpr, hasSyntacticForm,
           InnerMatcher.matches(*SyntForm, Finder, Builder));
 }
 
+/// \brief Matches C++ initializer list expressions.
+///
+/// Given
+/// \code
+///   std::vector<int> a({ 1, 2, 3 });
+///   std::vector<int> b = { 4, 5 };
+///   int c[] = { 6, 7 };
+///   std::pair<int, int> d = { 8, 9 };
+/// \endcode
+/// cxxStdInitializerListExpr()
+///   matches "{ 1, 2, 3 }" and "{ 4, 5 }"
+const internal::VariadicDynCastAllOfMatcher<Stmt,
+  CXXStdInitializerListExpr> cxxStdInitializerListExpr;
+
 /// \brief Matches implicit initializers of init list expressions.
 ///
 /// Given

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -153,6 +153,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(cxxRecordDecl);
   REGISTER_MATCHER(cxxReinterpretCastExpr);
   REGISTER_MATCHER(cxxStaticCastExpr);
+  REGISTER_MATCHER(cxxStdInitializerListExpr);
   REGISTER_MATCHER(cxxTemporaryObjectExpr);
   REGISTER_MATCHER(cxxThisExpr);
   REGISTER_MATCHER(cxxThrowExpr);

clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp

@@ -1020,6 +1020,29 @@ TEST(InitListExpression, MatchesInitListExpression) {
     matches("int i[1] = {42, [0] = 43};", integerLiteral(equals(42))));
 }
 
+TEST(CXXStdInitializerListExpression, MatchesCXXStdInitializerListExpression) {
+  const std::string code = "namespace std {"
+                           "template <typename> class initializer_list {"
+                           "  public: initializer_list() noexcept {}"
+                           "};"
+                           "}"
+                           "struct A {"
+                           "  A(std::initializer_list<int>) {}"
+                           "};";
+  EXPECT_TRUE(matches(code + "A a{0};",
+                      cxxConstructExpr(has(cxxStdInitializerListExpr()),
+                                       hasDeclaration(cxxConstructorDecl(
+                                           ofClass(hasName("A")))))));
+  EXPECT_TRUE(matches(code + "A a = {0};",
+                      cxxConstructExpr(has(cxxStdInitializerListExpr()),
+                                       hasDeclaration(cxxConstructorDecl(
+                                           ofClass(hasName("A")))))));
+
+  EXPECT_TRUE(notMatches("int a[] = { 1, 2 };", cxxStdInitializerListExpr()));
+  EXPECT_TRUE(notMatches("struct B { int x, y; }; B b = { 5, 6 };",
+                         cxxStdInitializerListExpr()));
+}
+
 TEST(UsingDeclaration, MatchesUsingDeclarations) {
   EXPECT_TRUE(matches("namespace X { int x; } using X::x;",
                       usingDecl()));