[PATCH v2] c++: Fix ICE with lambda in operator function [PR93597]

[Marek Polacek]

On Wed, Feb 05, 2020 at 04:40:50PM -0500, Jason Merrill wrote:
> On 2/5/20 4:31 PM, Marek Polacek wrote:
> > If we are going to use get_first_fn let's make sure we operate
> > on is_overloaded_fn, as the rest of the codebase does.
> > 
> > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> > 
> > 	PR c++/93597 - ICE with lambda in operator function.
> > 	* name-lookup.c (maybe_save_operator_binding): Check is_overloaded_fn.
> > 
> > 	* g++.dg/cpp0x/lambda/lambda-93597.C: New test.
> > ---
> >   gcc/cp/name-lookup.c                             | 13 ++++++++-----
> >   gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C |  8 ++++++++
> >   2 files changed, 16 insertions(+), 5 deletions(-)
> >   create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C
> > 
> > diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
> > index 2447166a444..aa539926332 100644
> > --- a/gcc/cp/name-lookup.c
> > +++ b/gcc/cp/name-lookup.c
> > @@ -7624,11 +7624,14 @@ maybe_save_operator_binding (tree e)
> >     if (!fns && (fns = op_unqualified_lookup (fnname)))
> >       {
> > -      tree fn = get_first_fn (fns);
> > -      if (DECL_CLASS_SCOPE_P (fn))
> > -	/* We don't need to remember class-scope functions, normal unqualified
> > -	   lookup will find them again.  */
> > -	return;
> > +      if (is_overloaded_fn (fns))
> > +	{
> > +	  tree fn = get_first_fn (fns);
> > +	  if (DECL_CLASS_SCOPE_P (fn))
> > +	    /* We don't need to remember class-scope functions, normal
> > +	       unqualified lookup will find them again.  */
> > +	    return;
> > +	}
> 
> I think we want to return early in this testcase, too, i.e. if lookup finds
> any class-scope declaration.

Ah okay, how about this, if it passes the usual testing?

-- >8 --
If we are going to use get_first_fn let's make sure we operate on
is_overloaded_fn, as the rest of the codebase does, and if lookup finds
any class-scope declaration, return early too.

	PR c++/93597 - ICE with lambda in operator function.
	* name-lookup.c (maybe_save_operator_binding): Check is_overloaded_fn.

	* g++.dg/cpp0x/lambda/lambda-93597.C: New test.
---
 gcc/cp/name-lookup.c                             | 8 ++++----
 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C | 8 ++++++++
 2 files changed, 12 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 2447166a444..8853c39f0eb 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -7624,10 +7624,10 @@ maybe_save_operator_binding (tree e)
 
   if (!fns && (fns = op_unqualified_lookup (fnname)))
     {
-      tree fn = get_first_fn (fns);
-      if (DECL_CLASS_SCOPE_P (fn))
-	/* We don't need to remember class-scope functions, normal unqualified
-	   lookup will find them again.  */
+      tree d = is_overloaded_fn (fns) ? get_first_fn (fns) : fns;
+      if (DECL_CLASS_SCOPE_P (d))
+	/* We don't need to remember class-scope functions or declarations,
+	   normal unqualified lookup will find them again.  */
 	return;
 
       bindings = tree_cons (fnname, fns, bindings);
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C
new file mode 100644
index 00000000000..257d9c7cdfd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-93597.C
@@ -0,0 +1,8 @@
+// PR c++/93597 - ICE with lambda in operator function.
+// { dg-do compile { target c++11 } }
+
+template <typename T>
+struct S {
+  using T ::operator<;
+  void operator==(T x) { [x] { 0 < x; }; }
+};

base-commit: d10cddeaad2a315c114063b7c1ff11c6a356ab65
-- 
Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA