[clang-tools-extra] [clang-tidy] support `return c ? a : b;` in bugprone-return-const-ref-from-parameter (PR #107657)

[Congcong Cai via cfe-commits]

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@@ -15,20 +16,24 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::bugprone {
 
 void ReturnConstRefFromParameterCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(
-      returnStmt(
-          hasReturnValue(declRefExpr(
-              to(parmVarDecl(hasType(hasCanonicalType(
-                                 qualType(lValueReferenceType(pointee(
-                                              qualType(isConstQualified()))))
-                                     .bind("type"))))
-                     .bind("param")))),
-          hasAncestor(
-              functionDecl(hasReturnTypeLoc(loc(qualType(
-                               hasCanonicalType(equalsBoundNode("type"))))))
-                  .bind("func")))
-          .bind("ret"),
-      this);
+  const auto DRef =
+      declRefExpr(
+          to(parmVarDecl(hasType(hasCanonicalType(
+                             qualType(lValueReferenceType(pointee(
+                                          qualType(isConstQualified()))))
+                                 .bind("type"))))
+                 .bind("param")))
+          .bind("dref");
+  const auto Func =
+      functionDecl(hasReturnTypeLoc(loc(
+                       qualType(hasCanonicalType(equalsBoundNode("type"))))))
+          .bind("func");
+
+  Finder->addMatcher(returnStmt(hasReturnValue(DRef), hasAncestor(Func)), this);
+  Finder->addMatcher(conditionalOperator(eachOf(hasTrueExpression(DRef),
----------------
HerrCai0907 wrote:

return should also in this pattern. we should not warn for the condition expression, instead, we should warn for return c?a:b


https://github.com/llvm/llvm-project/pull/107657