diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp index 8d9250217a7799..a96e1c1e657237 100644 --- a/clang/lib/Sema/SemaType.cpp +++ b/clang/lib/Sema/SemaType.cpp @@ -8120,10 +8120,12 @@ bool Sema::hasVisibleDefinition(NamedDecl *D, NamedDecl **Suggested, } else if (auto *ED = dyn_cast(D)) { if (auto *Pattern = ED->getTemplateInstantiationPattern()) ED = Pattern; - if (OnlyNeedComplete && ED->isFixed()) { - // If the enum has a fixed underlying type, and we're only looking for a - // complete type (not a definition), any visible declaration of it will - // do. + if (OnlyNeedComplete && (ED->isFixed() || getLangOpts().MSVCCompat)) { + // If the enum has a fixed underlying type, it may have been forward + // declared. In -fms-compatibility, `enum Foo;` will also forward declare + // the enum and assign it the underlying type of `int`. Since we're only + // looking for a complete type (not a definition), any visible declaration + // of it will do. *Suggested = nullptr; for (auto *Redecl : ED->redecls()) { if (isVisible(Redecl)) diff --git a/clang/test/Modules/Inputs/ms-enums/A.h b/clang/test/Modules/Inputs/ms-enums/A.h new file mode 100644 index 00000000000000..168445221c0357 --- /dev/null +++ b/clang/test/Modules/Inputs/ms-enums/A.h @@ -0,0 +1 @@ +enum fwd_enum; diff --git a/clang/test/Modules/Inputs/ms-enums/B.h b/clang/test/Modules/Inputs/ms-enums/B.h new file mode 100644 index 00000000000000..7a13ba4d72d41f --- /dev/null +++ b/clang/test/Modules/Inputs/ms-enums/B.h @@ -0,0 +1 @@ +#include "A.h" diff --git a/clang/test/Modules/Inputs/ms-enums/module.map b/clang/test/Modules/Inputs/ms-enums/module.map new file mode 100644 index 00000000000000..d9aed01430c41f --- /dev/null +++ b/clang/test/Modules/Inputs/ms-enums/module.map @@ -0,0 +1,2 @@ +module A { header "A.h" } +module B { header "B.h" } diff --git a/clang/test/Modules/ms-enums.cpp b/clang/test/Modules/ms-enums.cpp new file mode 100644 index 00000000000000..b3a377c6fa634b --- /dev/null +++ b/clang/test/Modules/ms-enums.cpp @@ -0,0 +1,12 @@ +// RUN: rm -rf %t +// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -fms-compatibility -x c++ -std=c++20 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/ms-enums %s -verify -fno-modules-error-recovery + +#include "B.h" +// expected-note@A.h:1 {{previous declaration is here}} +// expected-note@A.h:1 2 {{previous definition is here}} + +fwd_enum gv_enum; // expected-error {{must be imported}} + +struct Foo { + enum fwd_enum enum_field; // expected-error 2 {{must be imported}} +};