On 6/24/20 7:27 PM, Marek Polacek wrote:
This is an ICE-on-invalid but I've been seeing it when reducing various testcases, so it's more important for me than usually.splice_late_return_type now checks that if we've seen a late return type, the function return type was auto. That's a fair assumption but grokdeclarator/cdk_function wasn't giving errors for function pointers and similar. So we want to perform various checks not only when funcdecl_p || inner_declarator == NULL. But only give the !late_return_type errors when funcdecl_p, to accept e.g. auto (*fp)() = f; in C++11. Here's a diff -w to ease the review: --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -12102,14 +12102,9 @@ grokdeclarator (const cp_declarator *declarator, /* Handle a late-specified return type. */ tree late_return_type = declarator->u.function.late_return_type; - if (funcdecl_p - /* This is the case e.g. for - using T = auto () -> int. */ - || inner_declarator == NULL) - { if (tree auto_node = type_uses_auto (type)) { - if (!late_return_type) + if (!late_return_type && funcdecl_p) { if (current_class_type && LAMBDA_TYPE_P (current_class_type)) @@ -12201,7 +12196,6 @@ grokdeclarator (const cp_declarator *declarator, "type specifier", name); return error_mark_node; } - } type = splice_late_return_type (type, late_return_type); if (type == error_mark_node) return error_mark_node; Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
gcc/cp/ChangeLog: PR c++/95820 * decl.c (grokdeclarator) <case cdk_function>: Check also pointers/references/... to functions. gcc/testsuite/ChangeLog: PR c++/95820 * g++.dg/cpp1y/auto-fn58.C: New test. --- gcc/cp/decl.c | 166 ++++++++++++------------- gcc/testsuite/g++.dg/cpp1y/auto-fn58.C | 13 ++ 2 files changed, 93 insertions(+), 86 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1y/auto-fn58.C diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 3afad5ca805..a9ec328c498 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -12102,106 +12102,100 @@ grokdeclarator (const cp_declarator *declarator,/* Handle a late-specified return type. */tree late_return_type = declarator->u.function.late_return_type; - if (funcdecl_p - /* This is the case e.g. for - using T = auto () -> int. */ - || inner_declarator == NULL) + if (tree auto_node = type_uses_auto (type)) { - if (tree auto_node = type_uses_auto (type)) + if (!late_return_type && funcdecl_p) { - if (!late_return_type) + if (current_class_type + && LAMBDA_TYPE_P (current_class_type)) + /* OK for C++11 lambdas. */; + else if (cxx_dialect < cxx14) { - if (current_class_type - && LAMBDA_TYPE_P (current_class_type)) - /* OK for C++11 lambdas. */; - else if (cxx_dialect < cxx14) - { - error_at (typespec_loc, "%qs function uses " - "%<auto%> type specifier without " - "trailing return type", name); - inform (typespec_loc, - "deduced return type only available " - "with %<-std=c++14%> or %<-std=gnu++14%>"); - } - else if (virtualp) - { - error_at (typespec_loc, "virtual function " - "cannot have deduced return type"); - virtualp = false; - } + error_at (typespec_loc, "%qs function uses " + "%<auto%> type specifier without " + "trailing return type", name); + inform (typespec_loc, + "deduced return type only available " + "with %<-std=c++14%> or %<-std=gnu++14%>"); } - else if (!is_auto (type) && sfk != sfk_conversion) + else if (virtualp) { - error_at (typespec_loc, "%qs function with trailing " - "return type has %qT as its type rather " - "than plain %<auto%>", name, type); - return error_mark_node; + error_at (typespec_loc, "virtual function " + "cannot have deduced return type"); + virtualp = false; } - else if (is_auto (type) && AUTO_IS_DECLTYPE (type)) + } + else if (!is_auto (type) && sfk != sfk_conversion) + { + error_at (typespec_loc, "%qs function with trailing " + "return type has %qT as its type rather " + "than plain %<auto%>", name, type); + return error_mark_node; + } + else if (is_auto (type) && AUTO_IS_DECLTYPE (type)) + { + if (funcdecl_p) + error_at (typespec_loc, + "%qs function with trailing return type " + "has %<decltype(auto)%> as its type " + "rather than plain %<auto%>", name); + else + error_at (typespec_loc, + "invalid use of %<decltype(auto)%>"); + return error_mark_node; + } + tree tmpl = CLASS_PLACEHOLDER_TEMPLATE (auto_node); + if (!tmpl) + if (tree late_auto = type_uses_auto (late_return_type)) + tmpl = CLASS_PLACEHOLDER_TEMPLATE (late_auto); + if (tmpl && funcdecl_p) + { + if (!dguide_name_p (unqualified_id)) { - if (funcdecl_p) - error_at (typespec_loc, - "%qs function with trailing return type " - "has %<decltype(auto)%> as its type " - "rather than plain %<auto%>", name); - else - error_at (typespec_loc, - "invalid use of %<decltype(auto)%>"); + error_at (declarator->id_loc, "deduced class " + "type %qD in function return type", + DECL_NAME (tmpl)); + inform (DECL_SOURCE_LOCATION (tmpl), + "%qD declared here", tmpl); return error_mark_node; } - tree tmpl = CLASS_PLACEHOLDER_TEMPLATE (auto_node); - if (!tmpl) - if (tree late_auto = type_uses_auto (late_return_type)) - tmpl = CLASS_PLACEHOLDER_TEMPLATE (late_auto); - if (tmpl && funcdecl_p) + else if (!late_return_type) { - if (!dguide_name_p (unqualified_id)) - { - error_at (declarator->id_loc, "deduced class " - "type %qD in function return type", - DECL_NAME (tmpl)); - inform (DECL_SOURCE_LOCATION (tmpl), - "%qD declared here", tmpl); - return error_mark_node; - } - else if (!late_return_type) - { - error_at (declarator->id_loc, "deduction guide " - "for %qT must have trailing return " - "type", TREE_TYPE (tmpl)); - inform (DECL_SOURCE_LOCATION (tmpl), - "%qD declared here", tmpl); - return error_mark_node; - } - else if (CLASS_TYPE_P (late_return_type) - && CLASSTYPE_TEMPLATE_INFO (late_return_type) - && (CLASSTYPE_TI_TEMPLATE (late_return_type) - == tmpl)) - /* OK */; - else - error ("trailing return type %qT of deduction guide " - "is not a specialization of %qT", - late_return_type, TREE_TYPE (tmpl)); + error_at (declarator->id_loc, "deduction guide " + "for %qT must have trailing return " + "type", TREE_TYPE (tmpl)); + inform (DECL_SOURCE_LOCATION (tmpl), + "%qD declared here", tmpl); + return error_mark_node; } - } - else if (late_return_type - && sfk != sfk_conversion) - { - if (late_return_type == error_mark_node) - return error_mark_node; - if (cxx_dialect < cxx11) - /* Not using maybe_warn_cpp0x because this should - always be an error. */ - error_at (typespec_loc, - "trailing return type only available " - "with %<-std=c++11%> or %<-std=gnu++11%>"); + else if (CLASS_TYPE_P (late_return_type) + && CLASSTYPE_TEMPLATE_INFO (late_return_type) + && (CLASSTYPE_TI_TEMPLATE (late_return_type) + == tmpl)) + /* OK */; else - error_at (typespec_loc, "%qs function with trailing " - "return type not declared with %<auto%> " - "type specifier", name); - return error_mark_node; + error ("trailing return type %qT of deduction guide " + "is not a specialization of %qT", + late_return_type, TREE_TYPE (tmpl)); } } + else if (late_return_type + && sfk != sfk_conversion) + { + if (late_return_type == error_mark_node) + return error_mark_node; + if (cxx_dialect < cxx11) + /* Not using maybe_warn_cpp0x because this should + always be an error. */ + error_at (typespec_loc, + "trailing return type only available " + "with %<-std=c++11%> or %<-std=gnu++11%>"); + else + error_at (typespec_loc, "%qs function with trailing " + "return type not declared with %<auto%> " + "type specifier", name); + return error_mark_node; + } type = splice_late_return_type (type, late_return_type); if (type == error_mark_node) return error_mark_node; diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn58.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn58.C new file mode 100644 index 00000000000..8c4f24ccc74 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn58.C @@ -0,0 +1,13 @@ +// PR c++/95820 +// { dg-do compile { target c++14 } } + +auto (*a)() -> bool = nullptr; +int (*b)() -> bool = nullptr; // { dg-error "function with trailing return type" } +int (**c)() -> bool = nullptr; // { dg-error "function with trailing return type" } +int (&d)() -> bool = nullptr; // { dg-error "function with trailing return type" } +int (*&e)() -> bool = nullptr; // { dg-error "function with trailing return type" } +int (f[])() -> bool = nullptr; // { dg-error "function with trailing return type" } +auto* (*g)() -> bool = nullptr; // { dg-error "function with trailing return type" } +decltype(auto) (*h)() -> bool = nullptr; // { dg-error "invalid use" } +decltype(auto)* (*i)() -> bool = nullptr; // { dg-error "function with trailing return type" } +decltype(auto)& (*j)() -> bool = nullptr; // { dg-error "function with trailing return type" } base-commit: ef6506e23691a72e1e724977e8ee8b9f3db74015
