Author: halbi2 Date: 2025-08-18T06:49:04-07:00 New Revision: 2a02147ff563cbfc70911b2518cfb8a256131b5b
URL: https://github.com/llvm/llvm-project/commit/2a02147ff563cbfc70911b2518cfb8a256131b5b DIFF: https://github.com/llvm/llvm-project/commit/2a02147ff563cbfc70911b2518cfb8a256131b5b.diff LOG: [clang] [Sema] Simplify Expr::isUnusedResultAWarning for CXXConstructExpr (#153116) …Expr Two tests have new warnings because `warn_unused_result` is now respected for constructor temporaries. These tests were newly added in #112521 last year. This is good because the new behavior is better than the old. @Sirraide and @Mick235711 what do you think about it? Added: Modified: clang/lib/AST/Expr.cpp clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp clang/test/SemaCXX/warn-unused-result.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp index 7cac655ef151c..e14cff552c922 100644 --- a/clang/lib/AST/Expr.cpp +++ b/clang/lib/AST/Expr.cpp @@ -2805,32 +2805,20 @@ bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc, case CXXTemporaryObjectExprClass: case CXXConstructExprClass: { - if (const CXXRecordDecl *Type = getType()->getAsCXXRecordDecl()) { - const auto *WarnURAttr = Type->getAttr<WarnUnusedResultAttr>(); - if (Type->hasAttr<WarnUnusedAttr>() || - (WarnURAttr && WarnURAttr->IsCXX11NoDiscard())) { - WarnE = this; - Loc = getBeginLoc(); - R1 = getSourceRange(); - return true; - } - } - const auto *CE = cast<CXXConstructExpr>(this); - if (const CXXConstructorDecl *Ctor = CE->getConstructor()) { - const auto *WarnURAttr = Ctor->getAttr<WarnUnusedResultAttr>(); - if (WarnURAttr && WarnURAttr->IsCXX11NoDiscard()) { - WarnE = this; - Loc = getBeginLoc(); - R1 = getSourceRange(); + const CXXRecordDecl *Type = getType()->getAsCXXRecordDecl(); - if (unsigned NumArgs = CE->getNumArgs()) - R2 = SourceRange(CE->getArg(0)->getBeginLoc(), - CE->getArg(NumArgs - 1)->getEndLoc()); - return true; - } - } + if ((Type && Type->hasAttr<WarnUnusedAttr>()) || + CE->hasUnusedResultAttr(Ctx)) { + WarnE = this; + Loc = getBeginLoc(); + R1 = getSourceRange(); + if (unsigned NumArgs = CE->getNumArgs()) + R2 = SourceRange(CE->getArg(0)->getBeginLoc(), + CE->getArg(NumArgs - 1)->getEndLoc()); + return true; + } return false; } diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp index 0012ab976baa5..7f933a4dcc6b2 100644 --- a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp +++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.nodiscard/p2.cpp @@ -115,7 +115,7 @@ void usage() { S(); // expected-warning {{ignoring temporary created by a constructor declared with 'nodiscard' attribute}} S('A'); // expected-warning {{ignoring temporary created by a constructor declared with 'nodiscard' attribute: Don't let that S-Char go!}} S(1); - S(2.2); + S(2.2); // expected-warning {{ignoring temporary created by a constructor declared with 'gnu::warn_unused_result' attribute}} Y(); // expected-warning {{ignoring temporary of type 'Y' declared with 'nodiscard' attribute: Don't throw me away either!}} S s; ConvertTo{}; // expected-warning {{ignoring return value of type 'ConvertTo' declared with 'nodiscard' attribute: Don't throw me away!}} diff --git a/clang/test/SemaCXX/warn-unused-result.cpp b/clang/test/SemaCXX/warn-unused-result.cpp index 447654eccd563..1f7913f1aa994 100644 --- a/clang/test/SemaCXX/warn-unused-result.cpp +++ b/clang/test/SemaCXX/warn-unused-result.cpp @@ -309,7 +309,7 @@ void use() { S<double>(2); // no warning S<int>(2); // expected-warning {{ignoring temporary of type 'S<int>' declared with 'nodiscard'}} - S<const char>(2); // no warning (warn_unused_result does not diagnose constructor temporaries) + S<const char>(2); // expected-warning {{ignoring temporary of type 'S<const char>' declared with 'clang::warn_unused_result' attribute}} // function should take precedence over type obtain2(1.0); // expected-warning {{ignoring return value of function declared with 'nodiscard'}} @@ -336,7 +336,7 @@ struct [[nodiscard]] G { void use2() { H{2}; // no warning H(2.0); // expected-warning {{ignoring temporary created by a constructor declared with 'nodiscard'}} - H("Hello"); // no warning (warn_unused_result does not diagnose constructor temporaries) + H("Hello"); // expected-warning {{ignoring temporary created by a constructor declared with 'warn_unused_result' attribute}} // no warning for explicit cast to void (void)H(2); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
