[PATCH] c++: ICE with throw inside concept [PR112437]

[PATCH] c++: ICE with throw inside concept [PR112437]

[Marek Polacek]

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/13/12?

-- >8 --
We crash in the loop at the end of treat_lvalue_as_rvalue_p for code
like

  template <class T>
  concept Throwable = requires(T x) { throw x; };

because the code assumes that we eventually reach sk_function_parms or
sk_try and bail, but in a concept we're in a sk_namespace.

We're already checking sk_try so we don't crash in a function-try-block,
but I've added a test anyway.

	PR c++/112437

gcc/cp/ChangeLog:

	* typeck.cc (treat_lvalue_as_rvalue_p): Bail out on sk_namespace in
	the move on throw of parms loop.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/concepts-throw1.C: New test.
	* g++.dg/eh/throw4.C: New test.
---
 gcc/cp/typeck.cc                             |  4 +++-
 gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C |  8 ++++++++
 gcc/testsuite/g++.dg/eh/throw4.C             | 13 +++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
 create mode 100644 gcc/testsuite/g++.dg/eh/throw4.C

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index a15eda3f5f8..4937022ff20 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -10863,7 +10863,9 @@ treat_lvalue_as_rvalue_p (tree expr, bool return_p)
       for (tree decl = b->names; decl; decl = TREE_CHAIN (decl))
 	if (decl == retval)
 	  return set_implicit_rvalue_p (move (expr));
-      if (b->kind == sk_function_parms || b->kind == sk_try)
+      if (b->kind == sk_function_parms
+	  || b->kind == sk_try
+	  || b->kind == sk_namespace)
 	return NULL_TREE;
     }
 }
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
new file mode 100644
index 00000000000..bc3e3b6891a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
@@ -0,0 +1,8 @@
+// PR c++/112437
+// { dg-do compile { target c++20 } }
+
+struct S {};
+template <class T>
+concept Throwable = requires(T x) { throw x; };
+
+bool a = Throwable<S>;
diff --git a/gcc/testsuite/g++.dg/eh/throw4.C b/gcc/testsuite/g++.dg/eh/throw4.C
new file mode 100644
index 00000000000..b474472de48
--- /dev/null
+++ b/gcc/testsuite/g++.dg/eh/throw4.C
@@ -0,0 +1,13 @@
+// PR c++/112437
+// { dg-do compile }
+
+struct S {};
+
+S
+foo (S s)
+try {
+  throw s;
+}
+catch (...) {
+  throw s;
+}

base-commit: d22d1a9346f27db41459738c6eb404f8f0956e6f
-- 
2.43.0

Re: [PATCH] c++: ICE with throw inside concept [PR112437]

[Jason Merrill]

On 1/31/24 18:41, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/13/12?

OK.

> -- >8 --
> We crash in the loop at the end of treat_lvalue_as_rvalue_p for code
> like
> 
>    template <class T>
>    concept Throwable = requires(T x) { throw x; };
> 
> because the code assumes that we eventually reach sk_function_parms or
> sk_try and bail, but in a concept we're in a sk_namespace.
> 
> We're already checking sk_try so we don't crash in a function-try-block,
> but I've added a test anyway.
> 
> 	PR c++/112437
> 
> gcc/cp/ChangeLog:
> 
> 	* typeck.cc (treat_lvalue_as_rvalue_p): Bail out on sk_namespace in
> 	the move on throw of parms loop.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/cpp2a/concepts-throw1.C: New test.
> 	* g++.dg/eh/throw4.C: New test.
> ---
>   gcc/cp/typeck.cc                             |  4 +++-
>   gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C |  8 ++++++++
>   gcc/testsuite/g++.dg/eh/throw4.C             | 13 +++++++++++++
>   3 files changed, 24 insertions(+), 1 deletion(-)
>   create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
>   create mode 100644 gcc/testsuite/g++.dg/eh/throw4.C
> 
> diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
> index a15eda3f5f8..4937022ff20 100644
> --- a/gcc/cp/typeck.cc
> +++ b/gcc/cp/typeck.cc
> @@ -10863,7 +10863,9 @@ treat_lvalue_as_rvalue_p (tree expr, bool return_p)
>         for (tree decl = b->names; decl; decl = TREE_CHAIN (decl))
>   	if (decl == retval)
>   	  return set_implicit_rvalue_p (move (expr));
> -      if (b->kind == sk_function_parms || b->kind == sk_try)
> +      if (b->kind == sk_function_parms
> +	  || b->kind == sk_try
> +	  || b->kind == sk_namespace)
>   	return NULL_TREE;
>       }
>   }
> diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
> new file mode 100644
> index 00000000000..bc3e3b6891a
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-throw1.C
> @@ -0,0 +1,8 @@
> +// PR c++/112437
> +// { dg-do compile { target c++20 } }
> +
> +struct S {};
> +template <class T>
> +concept Throwable = requires(T x) { throw x; };
> +
> +bool a = Throwable<S>;
> diff --git a/gcc/testsuite/g++.dg/eh/throw4.C b/gcc/testsuite/g++.dg/eh/throw4.C
> new file mode 100644
> index 00000000000..b474472de48
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/eh/throw4.C
> @@ -0,0 +1,13 @@
> +// PR c++/112437
> +// { dg-do compile }
> +
> +struct S {};
> +
> +S
> +foo (S s)
> +try {
> +  throw s;
> +}
> +catch (...) {
> +  throw s;
> +}
> 
> base-commit: d22d1a9346f27db41459738c6eb404f8f0956e6f