https://github.com/to268 updated https://github.com/llvm/llvm-project/pull/189722
>From 121baa9a5477c079f55d8f5cea373991c979159d Mon Sep 17 00:00:00 2001 From: Tony Guillot <[email protected]> Date: Tue, 31 Mar 2026 19:30:33 +0200 Subject: [PATCH 1/3] Fixed C23 auto when an array type was specified for a `char *` --- clang/docs/ReleaseNotes.rst | 13 +++++++------ clang/lib/Sema/SemaTemplateDeduction.cpp | 10 ---------- clang/test/C/C23/n3007.c | 2 -- clang/test/CodeGen/auto.c | 1 - clang/test/Sema/c2x-auto.c | 17 ++++++++++++----- 5 files changed, 19 insertions(+), 24 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index bbbd3a34e01d6..10588c4c8df08 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -113,7 +113,7 @@ Clang Python Bindings Potentially Breaking Changes ``locations`` argument are passed. Previousy, ``locations`` took precedence. - ``_CXUnsavedFile`` will be renamed to ``UnsavedFile`` for consistency. ``UnsavedFile`` is already available to use and existing uses should - be adapted to refer to it instead. ``_CXUnsavedFile`` will be removed in a + be adapted to refer to it instead. ``_CXUnsavedFile`` will be removed in a future release. What's New in Clang |release|? @@ -324,7 +324,7 @@ Improvements to Clang's diagnostics when accessing a member function on a past-the-end array element. (#GH179128) -- Added a missing space to the FixIt for the ``implicit-int`` group of diagnostics and +- Added a missing space to the FixIt for the ``implicit-int`` group of diagnostics and made sure that only one such diagnostic and FixIt is emitted per declaration group. (#GH179354) - Fixed the Fix-It insertion point for ``expected ';' after alias declaration`` @@ -337,7 +337,7 @@ Improvements to Clang's diagnostics - The ``-Wloop-analysis`` warning has been extended to catch more cases of variable modification inside lambda expressions (#GH132038). -- Clang now emits ``-Wsizeof-pointer-memaccess`` when snprintf/vsnprintf use the sizeof +- Clang now emits ``-Wsizeof-pointer-memaccess`` when snprintf/vsnprintf use the sizeof the destination buffer(dynamically allocated) in the len parameter(#GH162366) - Added ``-Wmodule-map-path-outside-directory`` (off by default) to warn on @@ -384,6 +384,7 @@ Bug Fixes in This Version - Correctly diagnosing and no longer crashing when ``export module foo`` (without a semicolon) are the final tokens in a module file. (#GH187771) - Fixed a crash in duplicate attribute checking caused by comparing constant arguments with different integer signedness. (#GH188259) +- Fixed the behavior in C23 of ``auto``, by emitting an error when an array type is specified for a ``char *``. (#GH162694) Bug Fixes to Compiler Builtins ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -406,7 +407,7 @@ Bug Fixes to C++ Support - Fixed a crash when diagnosing an invalid static member function with an explicit object parameter (#GH177741) - Fixed a crash when instantiating an invalid out-of-line static data member definition in a local class. (#GH176152) - Fixed a crash when pack expansions are used as arguments for non-pack parameters of built-in templates. (#GH180307) -- Fixed a bug where captured variables in non-mutable lambdas were incorrectly treated as mutable +- Fixed a bug where captured variables in non-mutable lambdas were incorrectly treated as mutable when used inside decltype in the return type. (#GH180460) - Fixed a crash when evaluating uninitialized GCC vector/ext_vector_type vectors in ``constexpr``. (#GH180044) - Fixed a crash when `explicit(bool)` is used with an incomplete enumeration. (#GH183887) @@ -414,8 +415,8 @@ Bug Fixes to C++ Support - Fixed a crash when an immediate-invoked ``consteval`` lambda is used as an invalid initializer. (#GH185270) - Fixed an assertion failure when using a global destructor with a target with a non-default program address space. (#GH186484) -- Inherited constructors in ``dllexport`` classes are now exported for ABI-compatible cases, matching - MSVC behavior. Constructors with variadic arguments or callee-cleanup parameters are not yet supported +- Inherited constructors in ``dllexport`` classes are now exported for ABI-compatible cases, matching + MSVC behavior. Constructors with variadic arguments or callee-cleanup parameters are not yet supported and produce a warning. (#GH162640) - Fix initialization of GRO when GRO-return type mismatches, as part of CWG2563. (#GH98744) diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp index f18a34415ba43..696609d937850 100644 --- a/clang/lib/Sema/SemaTemplateDeduction.cpp +++ b/clang/lib/Sema/SemaTemplateDeduction.cpp @@ -5224,16 +5224,6 @@ Sema::DeduceAutoType(TypeLoc Type, Expr *Init, QualType &Result, return TemplateDeductionResult::Success; } - // Make sure that we treat 'char[]' equaly as 'char*' in C23 mode. - auto *String = dyn_cast<StringLiteral>(Init); - if (getLangOpts().C23 && String && Type.getType()->isArrayType()) { - Diag(Type.getBeginLoc(), diag::ext_c23_auto_non_plain_identifier); - TypeLoc TL = TypeLoc(Init->getType(), Type.getOpaqueData()); - Result = SubstituteDeducedTypeTransform(*this, DependentResult).Apply(TL); - assert(!Result.isNull() && "substituting DependentTy can't fail"); - return TemplateDeductionResult::Success; - } - // Emit a warning if 'auto*' is used in pedantic and in C23 mode. if (getLangOpts().C23 && Type.getType()->isPointerType()) { Diag(Type.getBeginLoc(), diag::ext_c23_auto_non_plain_identifier); diff --git a/clang/test/C/C23/n3007.c b/clang/test/C/C23/n3007.c index b8b84519fc19d..46bbfa48dda50 100644 --- a/clang/test/C/C23/n3007.c +++ b/clang/test/C/C23/n3007.c @@ -107,12 +107,10 @@ void test_misc(void) { auto something; // expected-error {{declaration of variable 'something' with deduced type 'auto' requires an initializer}} auto test_char = 'A'; auto test_char_ptr = "test"; - auto test_char_ptr2[] = "another test"; // expected-warning {{type inference of a declaration other than a plain identifier with optional trailing attributes is a Clang extension}} auto auto_size = sizeof(auto); // expected-error {{expected expression}} _Static_assert(_Generic(test_char, int : 1)); _Static_assert(_Generic(test_char_ptr, char * : 1)); - _Static_assert(_Generic(test_char_ptr2, char * : 1)); } void test_no_integer_promotions(void) { diff --git a/clang/test/CodeGen/auto.c b/clang/test/CodeGen/auto.c index e5bc1bf66138f..844fd37b309b9 100644 --- a/clang/test/CodeGen/auto.c +++ b/clang/test/CodeGen/auto.c @@ -7,7 +7,6 @@ void basic_types(void) { auto bl = true; // CHECK: alloca i8 auto chr = 'A'; // CHECK: alloca i{{8|32}} auto str = "Test"; // CHECK: alloca ptr - auto str2[] = "Test"; // CHECK: alloca [5 x i8] auto nptr = nullptr; // CHECK: alloca ptr } diff --git a/clang/test/Sema/c2x-auto.c b/clang/test/Sema/c2x-auto.c index 7d62db9ea6c28..6b92690003645 100644 --- a/clang/test/Sema/c2x-auto.c +++ b/clang/test/Sema/c2x-auto.c @@ -84,16 +84,16 @@ void test_qualifiers(const int y) { _Static_assert(_Generic(pc, int * : 1)); } -void test_strings(void) { +void test_parens(void) { auto str = "this is a string"; - auto str2[] = "this is a string"; // expected-warning {{type inference of a declaration other than a plain identifier with optional trailing attributes is a Clang extension}} - auto (str3) = "this is a string"; - auto (((str4))) = "this is a string"; + auto (str2) = "this is a string"; + auto (((str3))) = "this is a string"; + auto ((((x)))) = 12; _Static_assert(_Generic(str, char * : 1)); _Static_assert(_Generic(str2, char * : 1)); _Static_assert(_Generic(str3, char * : 1)); - _Static_assert(_Generic(str4, char * : 1)); + _Static_assert(_Generic(x, int : 1)); } void test_pointers(void) { @@ -137,3 +137,10 @@ void test_scopes(void) { expected-error {{'auto' not allowed in function return type}} return x; } + + +void test_incompatible_initializer(void) { + auto s1[] = "test"; // expected-error {{variable 's1' with type 'auto[]' has incompatible initializer of type 'char[5]'}} + auto s2[4] = "test"; // expected-error {{variable 's2' with type 'auto[4]' has incompatible initializer of type 'char[5]'}} + auto s3[5] = "test"; // expected-error {{variable 's3' with type 'auto[5]' has incompatible initializer of type 'char[5]'}} +} >From f89db10f42b0c4dcd6c4403a362625f3d4e8f35c Mon Sep 17 00:00:00 2001 From: Tony Guillot <[email protected]> Date: Tue, 31 Mar 2026 19:39:49 +0200 Subject: [PATCH 2/3] Formatted ReleaseNotes --- clang/docs/ReleaseNotes.rst | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 10588c4c8df08..cb69dbef3d2e5 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -113,7 +113,7 @@ Clang Python Bindings Potentially Breaking Changes ``locations`` argument are passed. Previousy, ``locations`` took precedence. - ``_CXUnsavedFile`` will be renamed to ``UnsavedFile`` for consistency. ``UnsavedFile`` is already available to use and existing uses should - be adapted to refer to it instead. ``_CXUnsavedFile`` will be removed in a + be adapted to refer to it instead. ``_CXUnsavedFile`` will be removed in a future release. What's New in Clang |release|? @@ -324,7 +324,7 @@ Improvements to Clang's diagnostics when accessing a member function on a past-the-end array element. (#GH179128) -- Added a missing space to the FixIt for the ``implicit-int`` group of diagnostics and +- Added a missing space to the FixIt for the ``implicit-int`` group of diagnostics and made sure that only one such diagnostic and FixIt is emitted per declaration group. (#GH179354) - Fixed the Fix-It insertion point for ``expected ';' after alias declaration`` @@ -337,7 +337,7 @@ Improvements to Clang's diagnostics - The ``-Wloop-analysis`` warning has been extended to catch more cases of variable modification inside lambda expressions (#GH132038). -- Clang now emits ``-Wsizeof-pointer-memaccess`` when snprintf/vsnprintf use the sizeof +- Clang now emits ``-Wsizeof-pointer-memaccess`` when snprintf/vsnprintf use the sizeof the destination buffer(dynamically allocated) in the len parameter(#GH162366) - Added ``-Wmodule-map-path-outside-directory`` (off by default) to warn on @@ -407,7 +407,7 @@ Bug Fixes to C++ Support - Fixed a crash when diagnosing an invalid static member function with an explicit object parameter (#GH177741) - Fixed a crash when instantiating an invalid out-of-line static data member definition in a local class. (#GH176152) - Fixed a crash when pack expansions are used as arguments for non-pack parameters of built-in templates. (#GH180307) -- Fixed a bug where captured variables in non-mutable lambdas were incorrectly treated as mutable +- Fixed a bug where captured variables in non-mutable lambdas were incorrectly treated as mutable when used inside decltype in the return type. (#GH180460) - Fixed a crash when evaluating uninitialized GCC vector/ext_vector_type vectors in ``constexpr``. (#GH180044) - Fixed a crash when `explicit(bool)` is used with an incomplete enumeration. (#GH183887) @@ -415,8 +415,8 @@ Bug Fixes to C++ Support - Fixed a crash when an immediate-invoked ``consteval`` lambda is used as an invalid initializer. (#GH185270) - Fixed an assertion failure when using a global destructor with a target with a non-default program address space. (#GH186484) -- Inherited constructors in ``dllexport`` classes are now exported for ABI-compatible cases, matching - MSVC behavior. Constructors with variadic arguments or callee-cleanup parameters are not yet supported +- Inherited constructors in ``dllexport`` classes are now exported for ABI-compatible cases, matching + MSVC behavior. Constructors with variadic arguments or callee-cleanup parameters are not yet supported and produce a warning. (#GH162640) - Fix initialization of GRO when GRO-return type mismatches, as part of CWG2563. (#GH98744) >From a5aa9b3dd65c4df098cc78628390fcec00b0540c Mon Sep 17 00:00:00 2001 From: Tony Guillot <[email protected]> Date: Wed, 1 Apr 2026 14:39:57 +0200 Subject: [PATCH 3/3] Improved N3007 test case --- clang/test/C/C23/n3007.c | 1 + 1 file changed, 1 insertion(+) diff --git a/clang/test/C/C23/n3007.c b/clang/test/C/C23/n3007.c index 46bbfa48dda50..881a7755f3467 100644 --- a/clang/test/C/C23/n3007.c +++ b/clang/test/C/C23/n3007.c @@ -107,6 +107,7 @@ void test_misc(void) { auto something; // expected-error {{declaration of variable 'something' with deduced type 'auto' requires an initializer}} auto test_char = 'A'; auto test_char_ptr = "test"; + auto test_char_ptr2[] = "another test"; // expected-error {{variable 'test_char_ptr2' with type 'auto[]' has incompatible initializer of type 'char[13]'}} auto auto_size = sizeof(auto); // expected-error {{expected expression}} _Static_assert(_Generic(test_char, int : 1)); _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
