[clang][ASTMatcher] Fix execution order of hasOperands submatchers (#104148)

`hasOperands` does not always execute matchers in the order they are
written. This can cause issue in code using bindings when one operand
matcher is relying on a binding set by the other. With this change, the
first matcher present in the code is always executed first and any
binding it sets are available to the second matcher.

Simple example with current version (1 match) and new version (2
matches):
```bash
> cat tmp.cpp
int a = 13;
int b = ((int) a) - a;
int c = a - ((int) a);

> clang-query tmp.cpp
clang-query> set traversal IgnoreUnlessSpelledInSource
clang-query> m binaryOperator(hasOperands(cStyleCastExpr(has(declRefExpr(hasDeclaration(valueDecl().bind("d"))))), declRefExpr(hasDeclaration(valueDecl(equalsBoundNode("d"))))))

Match #1:

tmp.cpp:1:1: note: "d" binds here
int a = 13;
^~~~~~~~~~
tmp.cpp:2:9: note: "root" binds here
int b = ((int)a) - a;
        ^~~~~~~~~~~~
1 match.

> ./build/bin/clang-query tmp.cpp
clang-query> set traversal IgnoreUnlessSpelledInSource
clang-query> m binaryOperator(hasOperands(cStyleCastExpr(has(declRefExpr(hasDeclaration(valueDecl().bind("d"))))), declRefExpr(hasDeclaration(valueDecl(equalsBoundNode("d"))))))

Match #1:

tmp.cpp:1:1: note: "d" binds here
    1 | int a = 13;
      | ^~~~~~~~~~
tmp.cpp:2:9: note: "root" binds here
    2 | int b = ((int)a) - a;
      |         ^~~~~~~~~~~~

Match #2:

tmp.cpp:1:1: note: "d" binds here
    1 | int a = 13;
      | ^~~~~~~~~~
tmp.cpp:3:9: note: "root" binds here
    3 | int c = a - ((int)a);
      |         ^~~~~~~~~~~~
2 matches.
```

If this should be documented or regression tested anywhere please let me
know where.

Author: nicovank

clang/docs/ReleaseNotes.rst

@@ -388,6 +388,9 @@ AST Matchers
 - Fixed an issue with the `hasName` and `hasAnyName` matcher when matching
   inline namespaces with an enclosing namespace of the same name.
 
+- Fixed an ordering issue with the `hasOperands` matcher occuring when setting a
+  binding in the first matcher and using it in the second matcher.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -6027,7 +6027,7 @@ AST_POLYMORPHIC_MATCHER_P2(
     internal::Matcher<Expr>, Matcher1, internal::Matcher<Expr>, Matcher2) {
   return internal::VariadicDynCastAllOfMatcher<Stmt, NodeType>()(
              anyOf(allOf(hasLHS(Matcher1), hasRHS(Matcher2)),
-                   allOf(hasLHS(Matcher2), hasRHS(Matcher1))))
+                   allOf(hasRHS(Matcher1), hasLHS(Matcher2))))
       .matches(Node, Finder, Builder);
 }
 

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

@@ -1745,6 +1745,18 @@ TEST(MatchBinaryOperator, HasOperands) {
   EXPECT_TRUE(notMatches("void x() { 0 + 1; }", HasOperands));
 }
 
+TEST(MatchBinaryOperator, HasOperandsEnsureOrdering) {
+  StatementMatcher HasOperandsWithBindings = binaryOperator(hasOperands(
+      cStyleCastExpr(has(declRefExpr(hasDeclaration(valueDecl().bind("d"))))),
+      declRefExpr(hasDeclaration(valueDecl(equalsBoundNode("d"))))));
+  EXPECT_TRUE(matches(
+      "int a; int b = ((int) a) + a;",
+      traverse(TK_IgnoreUnlessSpelledInSource, HasOperandsWithBindings)));
+  EXPECT_TRUE(matches(
+      "int a; int b = a + ((int) a);",
+      traverse(TK_IgnoreUnlessSpelledInSource, HasOperandsWithBindings)));
+}
+
 TEST(Matcher, BinaryOperatorTypes) {
   // Integration test that verifies the AST provides all binary operators in
   // a way we expect.