[clang][ASTMatchers] Add arrayTypeLoc ast matcher for ArrayTypeLoc (llvm#168990)

There's `arrayType` matcher for matching `ArrayType`, but no matcher for
`ArrayTypeLoc`. This change complements it.

Note that there's already `hasElementTypeLoc` matcher, which was
declared together with the `hasElementType` matcher.

Author: yuhaouy

clang/docs/LibASTMatchersReference.html

@@ -2449,6 +2449,18 @@ <h2 id="decl-matchers">Node Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TypeLoc.html">TypeLoc</a>&gt;</td><td class="name" onclick="toggle('arrayTypeLoc0')"><a name="arrayTypeLoc0Anchor">arrayTypeLoc</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ArrayTypeLoc.html">ArrayTypeLoc</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="arrayTypeLoc0"><pre>Matches `ArrayTypeLoc`s.
+
+Given
+  int a[] = {1, 2};
+  int b[3];
+  void f() { int c[a[0]]; }
+arrayTypeLoc()
+  matches "int a[]", "int b[3]" and "int c[a[0]]".
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TypeLoc.html">TypeLoc</a>&gt;</td><td class="name" onclick="toggle('pointerTypeLoc0')"><a name="pointerTypeLoc0Anchor">pointerTypeLoc</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1PointerTypeLoc.html">PointerTypeLoc</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="pointerTypeLoc0"><pre>Matches pointer `TypeLoc`s.
 

clang/docs/ReleaseNotes.rst

@@ -689,6 +689,7 @@ AST Matchers
 - Fixed detection of explicit parameter lists in ``LambdaExpr``. (#GH168452)
 - Added ``hasExplicitParameters`` for ``LambdaExpr`` as an output attribute to
   AST JSON dumps.
+- Add ``arrayTypeLoc`` matcher for matching ``ArrayTypeLoc``.
 
 clang-format
 ------------

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -7003,6 +7003,19 @@ AST_MATCHER_P(ReferenceTypeLoc, hasReferentLoc, internal::Matcher<TypeLoc>,
   return ReferentMatcher.matches(Node.getPointeeLoc(), Finder, Builder);
 }
 
+/// Matches `ArrayTypeLoc`s.
+///
+/// Given
+/// \code
+///   int a[] = {1, 2};
+///   int b[3];
+///   void f() { int c[a[0]]; }
+/// \endcode
+/// arrayTypeLoc()
+///   matches "int a[]", "int b[3]" and "int c[a[0]]".
+extern const internal::VariadicDynCastAllOfMatcher<TypeLoc, ArrayTypeLoc>
+    arrayTypeLoc;
+
 /// Matches template specialization `TypeLoc`s.
 ///
 /// Given

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -807,6 +807,7 @@ const internal::VariadicDynCastAllOfMatcher<TypeLoc, PointerTypeLoc>
     pointerTypeLoc;
 const internal::VariadicDynCastAllOfMatcher<TypeLoc, ReferenceTypeLoc>
     referenceTypeLoc;
+const internal::VariadicDynCastAllOfMatcher<TypeLoc, ArrayTypeLoc> arrayTypeLoc;
 const internal::VariadicDynCastAllOfMatcher<TypeLoc,
                                             TemplateSpecializationTypeLoc>
     templateSpecializationTypeLoc;

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -138,6 +138,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(argumentCountAtLeast);
   REGISTER_MATCHER(arraySubscriptExpr);
   REGISTER_MATCHER(arrayType);
+  REGISTER_MATCHER(arrayTypeLoc);
   REGISTER_MATCHER(asString);
   REGISTER_MATCHER(asmStmt);
   REGISTER_MATCHER(atomicExpr);

clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp

@@ -2353,6 +2353,26 @@ TEST_P(ASTMatchersTest, ReferenceTypeLocTest_BindsToAnyRvalueReferenceTypeLoc) {
   EXPECT_TRUE(matches("float&& r = 3.0;", matcher));
 }
 
+TEST_P(ASTMatchersTest, ArrayTypeLocTest_BindsToAnyArrayTypeLoc) {
+  auto matcher = varDecl(hasName("x"), hasTypeLoc(arrayTypeLoc()));
+  EXPECT_TRUE(matches("int x[3];", matcher));
+  EXPECT_TRUE(matches("float x[3];", matcher));
+  EXPECT_TRUE(matches("char x[3];", matcher));
+  EXPECT_TRUE(matches("void* x[3];", matcher));
+  EXPECT_TRUE(matches("const int x[3] = {1, 2, 3};", matcher));
+  EXPECT_TRUE(matches("int x[3][4];", matcher));
+  EXPECT_TRUE(matches("void foo(int x[]);", matcher));
+  EXPECT_TRUE(matches("int a[] = {1, 2}; void foo() {int x[a[0]];}", matcher));
+}
+
+TEST_P(ASTMatchersTest, ArrayTypeLocTest_DoesNotBindToNonArrayTypeLoc) {
+  auto matcher = varDecl(hasName("x"), hasTypeLoc(arrayTypeLoc()));
+  EXPECT_TRUE(notMatches("int x;", matcher));
+  EXPECT_TRUE(notMatches("float x;", matcher));
+  EXPECT_TRUE(notMatches("char x;", matcher));
+  EXPECT_TRUE(notMatches("void* x;", matcher));
+}
+
 TEST_P(ASTMatchersTest,
        TemplateSpecializationTypeLocTest_BindsToVarDeclTemplateSpecialization) {
   if (!GetParam().isCXX()) {