llvmorg-github-actions[bot] wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Alexsander Borges Damaceno (AlexsanderDamaceno) <details> <summary>Changes</summary> For [[maybe_unused]] written before the 'using' keyword of an alias-declaration: `[[maybe_unused]] using T = int;` Clang currently reports only: `error: an attribute list cannot appear here ` with no indication of where the attribute should actually go `Parser::DiagnoseProhibitedAttributes` already provides exactly this behavior, emitting a more helpful fix-it that suggests moving the attribute to the correct location. ParseUsingDeclaration already uses it without pass the FixItLoc location this way the fix-it sugestion is not show for using decl. This patch passes the right location when the attribute is `[[maybe_unused]]`, making the fix-it appear for the user. Improvement suggestion link: https://github.com/llvm/llvm-project/issues/155787 --- Full diff: https://github.com/llvm/llvm-project/pull/223910.diff 2 Files Affected: - (modified) clang/lib/Parse/ParseDeclCXX.cpp (+4-1) - (modified) clang/test/Parser/cxx0x-attributes.cpp (+4) ``````````diff diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp index 893989bd2398f..c9d133f5e341c 100644 --- a/clang/lib/Parse/ParseDeclCXX.cpp +++ b/clang/lib/Parse/ParseDeclCXX.cpp @@ -749,7 +749,10 @@ Parser::DeclGroupPtrTy Parser::ParseUsingDeclaration( return nullptr; } - ProhibitAttributes(PrefixAttrs); + SourceLocation MisplacedAttrFixItLoc; + if (PrefixAttrs.hasAttribute(ParsedAttr::AT_Unused)) + MisplacedAttrFixItLoc = Tok.getLocation(); + ProhibitAttributes(PrefixAttrs, MisplacedAttrFixItLoc); Decl *DeclFromDeclSpec = nullptr; Scope *CurScope = getCurScope(); diff --git a/clang/test/Parser/cxx0x-attributes.cpp b/clang/test/Parser/cxx0x-attributes.cpp index 220fddb98127a..2f3329d558dca 100644 --- a/clang/test/Parser/cxx0x-attributes.cpp +++ b/clang/test/Parser/cxx0x-attributes.cpp @@ -200,6 +200,10 @@ using T [[noreturn]] = int; // expected-error {{'noreturn' attribute only applie using V = int; // expected-note {{previous}} using V [[gnu::vector_size(16)]] = int; // expected-error {{redefinition with different types}} +void using_alias_in_block() { + [[maybe_unused]] using BlockAlias = int; // expected-error {{misplaced attributes; expected attributes here}} +} + auto trailing() -> [[]] const int; // expected-error {{an attribute list cannot appear here}} auto trailing() -> const [[]] int; // expected-error {{an attribute list cannot appear here}} auto trailing() -> const int [[]]; `````````` </details> https://github.com/llvm/llvm-project/pull/223910 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
