[gcc/devel/c++-coroutines] c++: Fix ICE with lambda in member operator (PR93279)

[Iain D Sandoe]

https://gcc.gnu.org/g:8b91e848130e45b427599ad30e99f96e447ea9aa

commit 8b91e848130e45b427599ad30e99f96e447ea9aa
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jan 24 18:20:56 2020 -0500

    c++: Fix ICE with lambda in member operator (PR93279)
    
    Here the problem was that we were remembering the lookup in template scope,
    and then trying to reuse that lookup in the instantiation without
    substituting into it at all.  The simplest solution is to not try to
    remember a lookup that finds a class-scope declaration, as in that case
    doing the normal lookup again at instantiation time will always find the
    right declarations.
    
    	PR c++/93279 - ICE with lambda in member operator.
    	* name-lookup.c (maybe_save_operator_binding): Don't remember
    	class-scope bindings.

Diff:
---
 gcc/cp/ChangeLog                                      |  6 ++++++
 gcc/cp/name-lookup.c                                  |  6 ++++++
 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template16.C | 15 +++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index cddf169..764b9cc 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,11 @@
 2020-01-24  Jason Merrill  <jason@redhat.com>
 
+	PR c++/93279 - ICE with lambda in member operator.
+	* name-lookup.c (maybe_save_operator_binding): Don't remember
+	class-scope bindings.
+
+2020-01-24  Jason Merrill  <jason@redhat.com>
+
 	PR c++/93377 - ICE with member alias in constraint.
 	* pt.c (any_template_parm_r): Look at template arguments for all
 	aliases, not only alias templates.
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index cd7a581..5721007 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -7616,6 +7616,12 @@ 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;
+
       bindings = tree_cons (fnname, fns, bindings);
       if (attr)
 	TREE_VALUE (attr) = bindings;
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template16.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template16.C
new file mode 100644
index 0000000..faaff68
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template16.C
@@ -0,0 +1,15 @@
+// PR c++/93279
+// { dg-do compile { target c++11 } }
+
+template <typename T> struct B { using f = int; };
+template <typename T, int N> struct E {
+  template <typename U, typename B<E>::f = 0>
+  void operator*(U l) { [l](T m) { m * l; }; }
+};
+
+int
+main ()
+{
+  E<E<float, 4>, 1> n;
+  n * 4.f;
+}