[ASTMatchers] Introduce Objective-C matchers `isClassMessage`, `isClassMethod`, and `isInstanceMethod`

[mwyman]

Summary

isClassMessage is an equivalent to isInstanceMessage for ObjCMessageExpr, but matches message expressions to classes.

isClassMethod and isInstanceMethod check whether a method declaration (or definition) is for a class method or instance method (respectively).

[benhamilton]

LGTM!

[mwyman]

Thanks. I don't believe I have commit access, so I'll need someone to commit this to trunk.

docs/LibASTMatchersReference.html

 
  matcher = objCMessageExpr(matchesSelector(hasUnarySelector());
  matches self.bodyView in the code below, but NOT the outer message
  invocation of "loadHTMLString:baseURL:".
     [self.bodyView loadHTMLString:html baseURL:NULL];
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('isClassMessage0')"><a name="isClassMessage0Anchor">isClassMessage</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isClassMessage0"><pre>Returns true when the Objective-C message is sent to a class.
+
+Example
+matcher = objcMessageExpr(isClassMessage())
+matches
+  [NSString stringWithFormat:@"format"];
+but not
+  NSString *x = @"hello";
+  [x containsString:@"h"];
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('isInstanceMessage0')"><a name="isInstanceMessage0Anchor">isInstanceMessage</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isInstanceMessage0"><pre>Returns true when the Objective-C message is sent to an instance.
 
 Example
-matcher = objcMessagaeExpr(isInstanceMessage())
+matcher = objcMessageExpr(isInstanceMessage())
 matches
   NSString *x = @"hello";
   [x containsString:@"h"];
 but not
   [NSString stringWithFormat:@"format"];
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMethodDecl.html">ObjCMethodDecl</a>&gt;</td><td class="name" onclick="toggle('isClassMethod0')"><a name="isClassMethod0Anchor">isClassMethod</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isClassMethod0"><pre>Returns true when the Objective-C method declaration is a class method.
+
+Example
+matcher = objcMethodDecl(isClassMethod())
+matches
+  @interface I + (void)foo; @end
+but not
+  @interface I - (void)bar; @end
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMethodDecl.html">ObjCMethodDecl</a>&gt;</td><td class="name" onclick="toggle('isInstanceMessage0')"><a name="isInstanceMessage0Anchor">isInstanceMethod</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isInstanceMethod0"><pre>Returns true when the Objective-C method declaration is an instance method.
+
+Example
+matcher = objcMethodDecl(isInstanceMethod())
+matches
+  @interface I - (void)bar; @end
+but not
+  @interface I + (void)foo; @end
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('matchesSelector0')"><a name="matchesSelector0Anchor">matchesSelector</a></td><td>std::string RegExp</td></tr>
 <tr><td colspan="4" class="doc" id="matchesSelector0"><pre>Matches ObjC selectors whose name contains
 a substring matched by the given RegExp.
  matcher = objCMessageExpr(matchesSelector("loadHTMLStringmatches the outer message expr in the code below, but NOT the message
  invocation for self.bodyView.
     [self.bodyView loadHTMLString:html baseURL:NULL];
 </pre></td></tr>
 

include/clang/ASTMatchers/ASTMatchers.h

 ///   [webView stringByEvaluatingJavaScriptFromString:webViewJavascript];
 /// \endcode
 AST_MATCHER_P(ObjCMessageExpr, hasReceiverType, internal::Matcher<QualType>,
               InnerMatcher) {
   const QualType TypeDecl = Node.getReceiverType();
   return InnerMatcher.matches(TypeDecl, Finder, Builder);
 }
 
+/// Returns true when the Objective-C method declaration is a class method.
+///
+/// Example
+/// matcher = objcMethodDecl(isClassMethod())
+/// matches
+/// \code
+/// @interface I + (void)foo; @end
+/// \endcode
+/// but not
+/// \code
+/// @interface I - (void)bar; @end
+/// \endcode
+AST_MATCHER(ObjCMethodDecl, isClassMethod) {
+  return Node.isClassMethod();
+}
+
+/// Returns true when the Objective-C method declaration is an instance method.
+///
+/// Example
+/// matcher = objcMethodDecl(isInstanceMethod())
+/// matches
+/// \code
+/// @interface I - (void)bar; @end
+/// \endcode
+/// but not
+/// \code
+/// @interface I + (void)foo; @end
+/// \endcode
+AST_MATCHER(ObjCMethodDecl, isInstanceMethod) {
+  return Node.isInstanceMethod();
+}
+
+/// Returns true when the Objective-C message is sent to a class.
+///
+/// Example
+/// matcher = objcMessageExpr(isClassMessage())
+/// matches
+/// \code
+///   [NSString stringWithFormat:@"format"];
+/// \endcode
+/// but not
+/// \code
+///   NSString *x = @"hello";
+///   [x containsString:@"h"];
+/// \endcode
+AST_MATCHER(ObjCMessageExpr, isClassMessage) {
+  return Node.isClassMessage();
+}
+
 /// Returns true when the Objective-C message is sent to an instance.
 ///
 /// Example
-/// matcher = objcMessagaeExpr(isInstanceMessage())
+/// matcher = objcMessageExpr(isInstanceMessage())
 /// matches
 /// \code
 ///   NSString *x = @"hello";
 ///   [x containsString:@"h"];
 /// \endcode
 /// but not
 /// \code
 ///   [NSString stringWithFormat:@"format"];

lib/ASTMatchers/Dynamic/Registry.cpp

RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(isAnyPointer);
   REGISTER_MATCHER(isArray);
   REGISTER_MATCHER(isArrow);
   REGISTER_MATCHER(isAssignmentOperator);
   REGISTER_MATCHER(isBaseInitializer);
   REGISTER_MATCHER(isBitField);
   REGISTER_MATCHER(isCatchAll);
   REGISTER_MATCHER(isClass);
+  REGISTER_MATCHER(isClassMessage);
+  REGISTER_MATCHER(isClassMethod);
   REGISTER_MATCHER(isConst);
   REGISTER_MATCHER(isConstQualified);
   REGISTER_MATCHER(isConstexpr);
   REGISTER_MATCHER(isCopyAssignmentOperator);
   REGISTER_MATCHER(isCopyConstructor);
   REGISTER_MATCHER(isDefaultConstructor);
   REGISTER_MATCHER(isDefaulted);
   REGISTER_MATCHER(isDefinition);
   REGISTER_MATCHER(isDelegatingConstructor);
   REGISTER_MATCHER(isDeleted);
   REGISTER_MATCHER(isExceptionVariable);
   REGISTER_MATCHER(isExpansionInFileMatching);
   REGISTER_MATCHER(isExpansionInMainFile);
   REGISTER_MATCHER(isExpansionInSystemHeader);
   REGISTER_MATCHER(isExplicit);
   REGISTER_MATCHER(isExplicitTemplateSpecialization);
   REGISTER_MATCHER(isExpr);
   REGISTER_MATCHER(isExternC);
   REGISTER_MATCHER(isFinal);
   REGISTER_MATCHER(isImplicit);
   REGISTER_MATCHER(isInTemplateInstantiation);
   REGISTER_MATCHER(isInline);
   REGISTER_MATCHER(isInstanceMessage);
+  REGISTER_MATCHER(isInstanceMethod);
   REGISTER_MATCHER(isInstantiated);
   REGISTER_MATCHER(isInstantiationDependent);
   REGISTER_MATCHER(isInteger);
   REGISTER_MATCHER(isIntegral);
   REGISTER_MATCHER(isLambda);
   REGISTER_MATCHER(isListInitialization);
   REGISTER_MATCHER(isMain);
   REGISTER_MATCHER(isMemberInitializer);

unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

EXPECT_TRUE(matchesObjC(
       objcMessageExpr(hasReceiver(declRefExpr(to(varDecl(hasName("x"))))))));
 
   EXPECT_FALSE(matchesObjC(
       "@interface NSString +(NSString *) stringWithFormat; @end "
       "void f() { [NSString stringWithFormat]; }",
       objcMessageExpr(hasReceiver(declRefExpr(to(varDecl(hasName("x"))))))));
 }
 
+TEST(Matcher, isClassMessage) {
+  EXPECT_TRUE(matchesObjC(
+      "@interface NSString +(NSString *) stringWithFormat; @end "
+      "void f() { [NSString stringWithFormat]; }",
+      objcMessageExpr(isClassMessage())));
+
+  EXPECT_FALSE(matchesObjC(
+      "@interface NSString @end "
+      "void f(NSString *x) {"
+      "[x containsString];"
+      "}",
+      objcMessageExpr(isClassMessage())));
+}
+
 TEST(Matcher, isInstanceMessage) {
   EXPECT_TRUE(matchesObjC(
       "@interface NSString @end "
       "void f(NSString *x) {"
       "[x containsString];"
       "}",
       objcMessageExpr(isInstanceMessage())));
 
   EXPECT_FALSE(matchesObjC(
       "@interface NSString +(NSString *) stringWithFormat; @end "
       "void f() { [NSString stringWithFormat]; }",
       objcMessageExpr(isInstanceMessage())));
 
 }
 
+TEST(Matcher, isClassMethod) {
+  EXPECT_TRUE(matchesObjC(
+    "@interface Bar + (void)bar; @end",
+    objcMethodDecl(isClassMethod())));
+
+  EXPECT_TRUE(matchesObjC(
+    "@interface Bar @end"
+    "@implementation Bar + (void)bar {} @end",
+    objcMethodDecl(isClassMethod())));
+
+  EXPECT_FALSE(matchesObjC(
+    "@interface Foo - (void)foo; @end",
+    objcMethodDecl(isClassMethod())));
+
+  EXPECT_FALSE(matchesObjC(
+    "@interface Foo @end "
+    "@implementation Foo - (void)foo {} @end",
+    objcMethodDecl(isClassMethod())));
+}
+
+TEST(Matcher, isInstanceMethod) {
+  EXPECT_TRUE(matchesObjC(
+    "@interface Foo - (void)foo; @end",
+    objcMethodDecl(isInstanceMethod())));
+
+  EXPECT_TRUE(matchesObjC(
+    "@interface Foo @end "
+    "@implementation Foo - (void)foo {} @end",
+    objcMethodDecl(isInstanceMethod())));
+
+  EXPECT_FALSE(matchesObjC(
+    "@interface Bar + (void)bar; @end",
+    objcMethodDecl(isInstanceMethod())));
+
+  EXPECT_FALSE(matchesObjC(
+    "@interface Bar @end"
+    "@implementation Bar + (void)bar {} @end",
+    objcMethodDecl(isInstanceMethod())));
+}
+
 TEST(MatcherCXXMemberCallExpr, On) {
   auto Snippet1 = R"cc(
         struct Y {
           void m();
         };
         void z(Y y) { y.m(); }
       )cc";
   auto Snippet2 = R"cc(