[PATCH] c++: Appertain standard attributes after array closing square bracket to array type rather than declarator [PR110345]

[Jakub Jelinek]

Hi!

For C++ 26 P2552R3 I went through all the spots (except modules) where
attribute-specifier-seq appears in the grammar and tried to construct
a testcase in all those spots, for now for [[deprecated]] attribute.

This is the second issue I found.  The comment already correctly says that
attributes after closing ] appertain to the array type, but we were
appending them to returned_attrs, so effectively applying them to the
declarator (as if they appeared right after declarator-id).

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2024-08-15  Jakub Jelinek  <ja...@redhat.com>

        PR c++/110345
        * decl.cc (grokdeclarator): Apply declarator->std_attributes
        for cdk_array to type, rather than chaining it to returned_attrs.

        * g++.dg/cpp0x/gen-attrs-82.C: New test.
        * g++.dg/gomp/attrs-3.C (foo): Expect different diagnostics for
        omp::directive attribute after closing square bracket of an automatic
        declaration and add a test with the attribute after array's
        declarator-id.

--- gcc/cp/decl.cc.jj   2024-08-14 18:19:28.000000000 +0200
+++ gcc/cp/decl.cc      2024-08-15 17:06:22.936426690 +0200
@@ -13317,9 +13317,8 @@ grokdeclarator (const cp_declarator *dec
            /* [dcl.array]/1:
 
               The optional attribute-specifier-seq appertains to the
-              array.  */
-           returned_attrs = attr_chainon (returned_attrs,
-                                          declarator->std_attributes);
+              array type.  */
+           decl_attributes (&type, declarator->std_attributes, 0);
          break;
 
        case cdk_function:
--- gcc/testsuite/g++.dg/cpp0x/gen-attrs-82.C.jj        2024-08-15 
17:15:47.982435384 +0200
+++ gcc/testsuite/g++.dg/cpp0x/gen-attrs-82.C   2024-08-15 17:16:17.112074964 
+0200
@@ -0,0 +1,4 @@
+// { dg-do compile { target c++11 } }
+
+int a [[gnu::common]] [2];
+int b[2] [[gnu::common]];      // { dg-warning "'common' attribute does not 
apply to types" }
--- gcc/testsuite/g++.dg/gomp/attrs-3.C.jj      2023-09-18 10:37:49.710048827 
+0200
+++ gcc/testsuite/g++.dg/gomp/attrs-3.C 2024-08-15 22:33:44.570617103 +0200
@@ -35,6 +35,7 @@ foo ()
   int *[[omp::directive (threadprivate (t3))]] c;              // { dg-warning 
"'omp::directive' scoped attribute directive ignored" }
   int &[[omp::directive (threadprivate (t4))]] d = b;          // { dg-warning 
"'omp::directive' scoped attribute directive ignored" }
   typedef int T [[omp::directive (threadprivate (t5))]];       // { dg-error 
"'omp::directive' not allowed to be specified in this context" }
-  int e[10] [[omp::directive (threadprivate (t6))]];           // { dg-error 
"'omp::directive' not allowed to be specified in this context" }
+  int e [[omp::directive (threadprivate (t6))]] [10];          // { dg-error 
"'omp::directive' not allowed to be specified in this context" }
+  int f[10] [[omp::directive (threadprivate (t6))]];           // { dg-warning 
"'omp::directive' scoped attribute directive ignored" }
   struct [[omp::directive (threadprivate (t7))]] S {};         // { dg-error 
"'omp::directive' not allowed to be specified in this context" }
 }


        Jakub