From 13709b518aa9769ef427e48ce5c9583fbe098777 Mon Sep 17 00:00:00 2001 From: David Malcolm Date: Fri, 23 Jun 2023 17:56:14 -0400 Subject: [PATCH] c++: provide #include hint for missing includes [PR110164] MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit PR c++/110164 notes that in cases where we have a forward decl of a std library type such as: std::array x; we emit this diagnostic: error: aggregate ‘std::array x’ has incomplete type and cannot be defined This patch adds this hint to the diagnostic: note: ‘std::array’ is defined in header ‘’; this is probably fixable by adding ‘#include ’ gcc/cp/ChangeLog: PR c++/110164 * cp-name-hint.h (maybe_suggest_missing_header): New decl. * decl.cc: Define INCLUDE_MEMORY. Add include of "cp/cp-name-hint.h". (start_decl_1): Call maybe_suggest_missing_header. * name-lookup.cc (maybe_suggest_missing_header): Remove "static". gcc/testsuite/ChangeLog: PR c++/110164 * g++.dg/diagnostic/missing-header-pr110164.C: New test. Signed-off-by: David Malcolm --- gcc/cp/cp-name-hint.h | 1 + gcc/cp/decl.cc | 10 ++++++++++ gcc/cp/name-lookup.cc | 2 +- .../g++.dg/diagnostic/missing-header-pr110164.C | 10 ++++++++++ 4 files changed, 22 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/diagnostic/missing-header-pr110164.C diff --git a/gcc/cp/cp-name-hint.h b/gcc/cp/cp-name-hint.h index bfa7c53c8f6..7693980138a 100644 --- a/gcc/cp/cp-name-hint.h +++ b/gcc/cp/cp-name-hint.h @@ -32,6 +32,7 @@ along with GCC; see the file COPYING3. If not see extern name_hint suggest_alternatives_for (location_t, tree, bool); extern name_hint suggest_alternatives_in_other_namespaces (location_t, tree); +extern name_hint maybe_suggest_missing_header (location_t, tree, tree); extern name_hint suggest_alternative_in_explicit_scope (location_t, tree, tree); extern name_hint suggest_alternative_in_scoped_enum (tree, tree); diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index c07a4a8d58d..60f107d50c4 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -27,6 +27,7 @@ along with GCC; see the file COPYING3. If not see line numbers. For example, the CONST_DECLs for enum values. */ #include "config.h" +#define INCLUDE_MEMORY #include "system.h" #include "coretypes.h" #include "target.h" @@ -46,6 +47,7 @@ along with GCC; see the file COPYING3. If not see #include "c-family/c-objc.h" #include "c-family/c-pragma.h" #include "c-family/c-ubsan.h" +#include "cp/cp-name-hint.h" #include "debug.h" #include "plugin.h" #include "builtins.h" @@ -5995,7 +5997,11 @@ start_decl_1 (tree decl, bool initialized) ; /* An auto type is ok. */ else if (TREE_CODE (type) != ARRAY_TYPE) { + auto_diagnostic_group d; error ("variable %q#D has initializer but incomplete type", decl); + maybe_suggest_missing_header (input_location, + TYPE_IDENTIFIER (type), + CP_TYPE_CONTEXT (type)); type = TREE_TYPE (decl) = error_mark_node; } else if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (type)))) @@ -6011,8 +6017,12 @@ start_decl_1 (tree decl, bool initialized) gcc_assert (CLASS_PLACEHOLDER_TEMPLATE (type)); else { + auto_diagnostic_group d; error ("aggregate %q#D has incomplete type and cannot be defined", decl); + maybe_suggest_missing_header (input_location, + TYPE_IDENTIFIER (type), + CP_TYPE_CONTEXT (type)); /* Change the type so that assemble_variable will give DECL an rtl we can live with: (mem (const_int 0)). */ type = TREE_TYPE (decl) = error_mark_node; diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc index 53b6870f067..74565184403 100644 --- a/gcc/cp/name-lookup.cc +++ b/gcc/cp/name-lookup.cc @@ -6796,7 +6796,7 @@ maybe_suggest_missing_std_header (location_t location, tree name) for NAME within SCOPE at LOCATION, or an empty name_hint if this isn't applicable. */ -static name_hint +name_hint maybe_suggest_missing_header (location_t location, tree name, tree scope) { if (scope == NULL_TREE) diff --git a/gcc/testsuite/g++.dg/diagnostic/missing-header-pr110164.C b/gcc/testsuite/g++.dg/diagnostic/missing-header-pr110164.C new file mode 100644 index 00000000000..15980071c38 --- /dev/null +++ b/gcc/testsuite/g++.dg/diagnostic/missing-header-pr110164.C @@ -0,0 +1,10 @@ +// { dg-require-effective-target c++11 } + +#include + +std::array a1; /* { dg-error "incomplete type" } */ +/* { dg-message "'std::array' is defined in header ''; this is probably fixable by adding '#include '" "hint" { target *-*-* } .-1 } */ + +std::array a2 {5}; /* { dg-error "incomplete type" } */ +/* { dg-message "'std::array' is defined in header ''; this is probably fixable by adding '#include '" "hint" { target *-*-* } .-1 } */ +