[clang-tools-extra] [WIP][clang-tidy] Ignore `if consteval` in else-after-return (PR #91588)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-tools-extra

@llvm/pr-subscribers-clang-tidy

Author: Jover (JoverZhang)

<details>
<summary>Changes</summary>

Fixes #<!-- -->91561.

---
Full diff: https://github.com/llvm/llvm-project/pull/91588.diff


2 Files Affected:

- (modified) clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp (+2-2) 
- (added) clang-tools-extra/test/clang-tidy/checkers/readability/else-after-return-if-consteval.cpp (+17) 


``````````diff
diff --git a/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp b/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
index 1e85caf688355..2b185e7594add 100644
--- a/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/ElseAfterReturnCheck.cpp
@@ -113,7 +113,7 @@ static bool containsDeclInScope(const Stmt *Node) {
 }
 
 static void removeElseAndBrackets(DiagnosticBuilder &Diag, ASTContext &Context,
-                           const Stmt *Else, SourceLocation ElseLoc) {
+                                  const Stmt *Else, SourceLocation ElseLoc) {
   auto Remap = [&](SourceLocation Loc) {
     return Context.getSourceManager().getExpansionLoc(Loc);
   };
@@ -172,7 +172,7 @@ void ElseAfterReturnCheck::registerMatchers(MatchFinder *Finder) {
       breakStmt().bind(InterruptingStr), cxxThrowExpr().bind(InterruptingStr)));
   Finder->addMatcher(
       compoundStmt(
-          forEach(ifStmt(unless(isConstexpr()),
+          forEach(ifStmt(unless(isConstexpr()), unless(isConsteval()),
                          hasThen(stmt(
                              anyOf(InterruptsControlFlow,
                                    compoundStmt(has(InterruptsControlFlow))))),
diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/else-after-return-if-consteval.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/else-after-return-if-consteval.cpp
new file mode 100644
index 0000000000000..6235d8623ca7b
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/else-after-return-if-consteval.cpp
@@ -0,0 +1,17 @@
+// RUN: %check_clang_tidy -std=c++20 %s readability-else-after-return %t 
+
+// Consteval if is an exception to the rule, we cannot remove the else.
+void f() {
+  if (sizeof(int) > 4) {
+    return;
+  } else {
+    return;
+  }
+  // CHECK-MESSAGES: [[@LINE-3]]:5: warning: do not use 'else' after 'return'
+
+  if consteval {
+    return;
+  } else {
+    return;
+  }
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/91588