c++: Try to complete decomp types [PR95328]

Message ID 20200527085006.GZ8462@tucnak
State New
Headers show
Series
  • c++: Try to complete decomp types [PR95328]
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Commit Message

Kees Cook via Gcc-patches May 27, 2020, 8:50 a.m.
Hi!

Two years ago Paolo has added the
  else if (processing_template_decl && !COMPLETE_TYPE_P (type))
    pedwarn (...);
lines into cp_finish_decomp.  For type dependent decl we punt much earlier,
but even for types which aren't type dependent COMPLETE_TYPE_P might be
false as this testcase shows, so this patch tries to complete_type first
(the reason for writing it that way is that it is then followed by another
else if and if complete_type returns error_mark_node, we shouldn't report
anything, as a bug should have been reported already.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2020-05-27  Jakub Jelinek  <jakub@redhat.com>

	PR c++/95328
	* decl.c (cp_finish_decomp): Call complete_type before checking
	COMPLETE_TYPE_P.

	* g++.dg/cpp1z/decomp53.C: New test.


	Jakub

Comments

Kees Cook via Gcc-patches May 28, 2020, 8:59 p.m. | #1
On 5/27/20 4:50 AM, Jakub Jelinek wrote:
> Hi!

> 

> Two years ago Paolo has added the

>    else if (processing_template_decl && !COMPLETE_TYPE_P (type))

>      pedwarn (...);

> lines into cp_finish_decomp.  For type dependent decl we punt much earlier,

> but even for types which aren't type dependent COMPLETE_TYPE_P might be

> false as this testcase shows, so this patch tries to complete_type first

> (the reason for writing it that way is that it is then followed by another

> else if and if complete_type returns error_mark_node, we shouldn't report

> anything, as a bug should have been reported already.

> 

> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?


OK.

> 2020-05-27  Jakub Jelinek  <jakub@redhat.com>

> 

> 	PR c++/95328

> 	* decl.c (cp_finish_decomp): Call complete_type before checking

> 	COMPLETE_TYPE_P.

> 

> 	* g++.dg/cpp1z/decomp53.C: New test.

> 

> --- gcc/cp/decl.c.jj	2020-05-22 11:07:21.884215758 +0200

> +++ gcc/cp/decl.c	2020-05-26 15:21:25.039880747 +0200

> @@ -8392,6 +8392,8 @@ cp_finish_decomp (tree decl, tree first,

>         error_at (loc, "cannot decompose lambda closure type %qT", type);

>         goto error_out;

>       }

> +  else if (processing_template_decl && complete_type (type) == error_mark_node)

> +    goto error_out;

>     else if (processing_template_decl && !COMPLETE_TYPE_P (type))

>       pedwarn (loc, 0, "structured binding refers to incomplete class type %qT",

>   	     type);

> --- gcc/testsuite/g++.dg/cpp1z/decomp53.C.jj	2020-05-26 15:25:01.397644953 +0200

> +++ gcc/testsuite/g++.dg/cpp1z/decomp53.C	2020-05-26 15:24:37.764998398 +0200

> @@ -0,0 +1,22 @@

> +// PR c++/95328

> +// { dg-do compile { target c++11 } }

> +// { dg-options "" }

> +

> +template <typename T>

> +struct S

> +{

> +  int a, b;

> +};

> +

> +template <typename T>

> +void

> +foo ()

> +{

> +  auto [a, b] = S<int>();	// { dg-warning "structured bindings only available with" "" { target c++14_down } }

> +}

> +

> +int

> +main ()

> +{

> +  foo<int> ();

> +}

> 

> 	Jakub

>

Patch

--- gcc/cp/decl.c.jj	2020-05-22 11:07:21.884215758 +0200
+++ gcc/cp/decl.c	2020-05-26 15:21:25.039880747 +0200
@@ -8392,6 +8392,8 @@  cp_finish_decomp (tree decl, tree first,
       error_at (loc, "cannot decompose lambda closure type %qT", type);
       goto error_out;
     }
+  else if (processing_template_decl && complete_type (type) == error_mark_node)
+    goto error_out;
   else if (processing_template_decl && !COMPLETE_TYPE_P (type))
     pedwarn (loc, 0, "structured binding refers to incomplete class type %qT",
 	     type);
--- gcc/testsuite/g++.dg/cpp1z/decomp53.C.jj	2020-05-26 15:25:01.397644953 +0200
+++ gcc/testsuite/g++.dg/cpp1z/decomp53.C	2020-05-26 15:24:37.764998398 +0200
@@ -0,0 +1,22 @@ 
+// PR c++/95328
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+template <typename T>
+struct S
+{
+  int a, b;
+};
+
+template <typename T>
+void
+foo ()
+{
+  auto [a, b] = S<int>();	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+}
+
+int
+main ()
+{
+  foo<int> ();
+}