[pushed] c++: generic lambda, local class, __func__ [PR108242]

Message ID 20230316221108.1138412-1-jason@redhat.com
State Accepted
Headers
Series [pushed] c++: generic lambda, local class, __func__ [PR108242] |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Jason Merrill March 16, 2023, 10:11 p.m. UTC
  Tested x86_64-pc-linux-gnu, applying to trunk.

-- 8< --

Here we are trying to do name lookup in a deferred instantiation of t() and
failing to find __func__.  tsubst_expr already tries to instantiate members
of local classes, but was failing with the partial instantiation of generic
lambdas.

	PR c++/108242

gcc/cp/ChangeLog:

	* pt.cc (tsubst_expr) [TAG_DEFN]: Handle partial instantiation.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/lambda-generic-func2.C: New test.
---
 gcc/cp/pt.cc                                   |  5 ++++-
 .../g++.dg/cpp1y/lambda-generic-func2.C        | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-generic-func2.C


base-commit: 1cc8814098bb46f9fca58a0b831fbf9a8574bdc9
  

Patch

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index ddbd73371b9..1072882e1a8 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -19341,7 +19341,10 @@  tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 
     case TAG_DEFN:
       tmp = tsubst (TREE_TYPE (t), args, complain, NULL_TREE);
-      if (CLASS_TYPE_P (tmp))
+      if (dependent_type_p (tmp))
+	/* This is a partial instantiation, try again when full.  */
+	add_stmt (build_min (TAG_DEFN, tmp));
+      else if (CLASS_TYPE_P (tmp))
 	{
 	  /* Local classes are not independent templates; they are
 	     instantiated along with their containing function.  And this
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-func2.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-func2.C
new file mode 100644
index 00000000000..ed541c7812f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-func2.C
@@ -0,0 +1,18 @@ 
+// PR c++/108242
+// { dg-do compile { target c++14 } }
+
+template<int F>
+void my_fun()
+{
+    [&](auto) {
+        static constexpr char const* fun_name = __func__;
+        struct t
+        {
+            t() { fun_name; };
+        } t1;
+    }(12);
+}
+
+int main() {
+    my_fun<1>();
+}