[c++]: Improve module-decl diagnostics [PR 98327]

The diagnostic for a misplaced module decl was essentially 'computer
says no', which isn't the most helpful.  This adjusts it to indicate
what would be acceptable.

	gcc/cp/
	* parser.c (cp_parser_module_declaration): Alter diagnostic
	text to say where is permissable.
	gcc/testsuite/
	* g++.dg/modules/mod-decl-1.C: Adjust.
	* g++.dg/modules/p0713-2.C: Adjust.
	* g++.dg/modules/p0713-3.C: Adjust.

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index d855e034458fb5bff4f1f3cbe9c10323adf8db4e..c713852fe93fb63b65c02d03c5d696ecc9f756be 100644 (file)
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -13726,19 +13726,22 @@ cp_parser_module_declaration (cp_parser *parser, module_parse mp_state,
       cp_lexer_consume_token (parser->lexer);
       cp_parser_require_pragma_eol (parser, token);
 
-      if ((mp_state != MP_PURVIEW && mp_state != MP_PURVIEW_IMPORTS)
+      if (!(mp_state == MP_PURVIEW || mp_state == MP_PURVIEW_IMPORTS)
          || !module_interface_p () || module_partition_p ())
        error_at (token->location,
-                 "private module fragment not permitted here");
+                 "private module fragment only permitted in purview"
+                 " of module interface or partition");
       else
        {
          mp_state = MP_PRIVATE_IMPORTS;
          sorry_at (token->location, "private module fragment");
        }
     }
-  else if (mp_state != MP_FIRST && mp_state != MP_GLOBAL)
+  else if (!(mp_state == MP_FIRST || mp_state == MP_GLOBAL))
     {
-      error_at (token->location, "module-declaration not permitted here");
+      /* Neither the first declaration, nor in a GMF.  */
+      error_at (token->location, "module-declaration only permitted as first"
+               " declaration, or ending a global module fragment");
     skip_eol:
       cp_parser_skip_to_pragma_eol (parser, token);
     }

diff --git a/gcc/testsuite/g++.dg/modules/mod-decl-1.C b/gcc/testsuite/g++.dg/modules/mod-decl-1.C
index b2665bec7437a551495a0857091b538feec7a3ec..23d34483dd7c883119274503bd77496b66e48fdf 100644 (file)
--- a/gcc/testsuite/g++.dg/modules/mod-decl-1.C
+++ b/gcc/testsuite/g++.dg/modules/mod-decl-1.C
@@ -6,11 +6,11 @@ export module frist;
 
 import frist; // { dg-error {cannot import module.* in its own purview} }
 
-module foo.second; // { dg-error "not permitted here" }
+module foo.second; // { dg-error "only permitted as" }
 
 namespace Foo 
 {
-module third;  // { dg-error "not permitted here" }
+module third;  // { dg-error "only permitted as" }
 }
 
 struct Baz
@@ -23,7 +23,7 @@ void Bink ()
   module fifth; // { dg-error "expected" }
 }
 
-module a.; // { dg-error "not permitted" }
+module a.; // { dg-error "only permitted as" }
 
 // { dg-prune-output "not writing module" }
 

diff --git a/gcc/testsuite/g++.dg/modules/p0713-2.C b/gcc/testsuite/g++.dg/modules/p0713-2.C
index c7846e450a90229e3b2d23371082facef8ac40f7..cb4ccb6c5f669adce8dce6108bf35f86613d2851 100644 (file)
--- a/gcc/testsuite/g++.dg/modules/p0713-2.C
+++ b/gcc/testsuite/g++.dg/modules/p0713-2.C
@@ -1,3 +1,3 @@
 // { dg-additional-options "-fmodules-ts" }
 int j;
-module; // { dg-error "not permitted" }
+module; // { dg-error "only permitted as" }

diff --git a/gcc/testsuite/g++.dg/modules/p0713-3.C b/gcc/testsuite/g++.dg/modules/p0713-3.C
index 3c539ebab3ea7a92e7753e4049f3c018f81a1d85..09d89b73b3fb8ca529ce9edd9090242ee856b802 100644 (file)
--- a/gcc/testsuite/g++.dg/modules/p0713-3.C
+++ b/gcc/testsuite/g++.dg/modules/p0713-3.C
@@ -1,6 +1,6 @@
 // { dg-additional-options "-fmodules-ts" }
 int k;
-module frob; // { dg-error "not permitted" }
+module frob; // { dg-error "only permitted as" }
 // { dg-prune-output "failed to read" }
 // { dg-prune-output "fatal error:" }
 // { dg-prune-output "compilation terminated" }