From: Nathaniel Shead <nathanieloshead@gmail.com>
Date: Thu, 10 Apr 2025 21:29:11 +0000 (+1000)
Subject: c++/modules: More fixes for merging DECL_MAYBE_DELETED functions
X-Git-Tag: basepoints/gcc-16~143
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f40e39515e0b7fa69bd50bad99f1f1b8c446692f;p=thirdparty%2Fgcc.git

c++/modules: More fixes for merging DECL_MAYBE_DELETED functions

My change in r15-9216 broke the case where we imported an uninstantiated
defaulted function over the top of one we had already finished.  This
patch ensures that we don't error for mismatches in this case.

gcc/cp/ChangeLog:

	* module.cc (trees_in::is_matching_decl): Don't check for
	mismatches when importing a DECL_MAYBE_DELETED function over one
	that's already finished.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/noexcept-4_a.H: New test.
	* g++.dg/modules/noexcept-4_b.C: New test.

Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
Reviewed-by: Jason Merrill <jason@redhat.com>
---

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 8efa18baff1..5ff5c462e79 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -12164,7 +12164,8 @@ trees_in::is_matching_decl (tree existing, tree decl, bool is_typedef)
 		}
 	    }
 	}
-      else if (!DEFERRED_NOEXCEPT_SPEC_P (d_spec)
+      else if (!DECL_MAYBE_DELETED (d_inner)
+	       && !DEFERRED_NOEXCEPT_SPEC_P (d_spec)
 	       && !comp_except_specs (d_spec, e_spec, ce_type))
 	{
 	  mismatch_msg = G_("conflicting %<noexcept%> specifier for "
@@ -12195,6 +12196,8 @@ trees_in::is_matching_decl (tree existing, tree decl, bool is_typedef)
       if (DECL_MAYBE_DELETED (e_inner) && !DECL_MAYBE_DELETED (d_inner)
 	  && DECL_DECLARED_CONSTEXPR_P (d_inner))
 	DECL_DECLARED_CONSTEXPR_P (e_inner) = true;
+      else if (!DECL_MAYBE_DELETED (e_inner) && DECL_MAYBE_DELETED (d_inner))
+	/* Nothing to do.  */;
       else if (DECL_DECLARED_CONSTEXPR_P (e_inner)
 	       != DECL_DECLARED_CONSTEXPR_P (d_inner))
 	{
diff --git a/gcc/testsuite/g++.dg/modules/noexcept-4_a.H b/gcc/testsuite/g++.dg/modules/noexcept-4_a.H
new file mode 100644
index 00000000000..b888a1b93e6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/noexcept-4_a.H
@@ -0,0 +1,6 @@
+// { dg-additional-options "-fmodule-header -std=c++20" }
+// { dg-module-cmi {} }
+
+struct exception_ptr {
+  friend bool operator==(const exception_ptr&, const exception_ptr&) = default;
+};
diff --git a/gcc/testsuite/g++.dg/modules/noexcept-4_b.C b/gcc/testsuite/g++.dg/modules/noexcept-4_b.C
new file mode 100644
index 00000000000..7cc55316c7c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/noexcept-4_b.C
@@ -0,0 +1,18 @@
+// { dg-additional-options "-fmodules -std=c++20" }
+
+struct exception_ptr {
+  friend bool operator==(const exception_ptr&, const exception_ptr&) = default;
+};
+
+void enqueue() {
+  exception_ptr e;
+  e == e;
+}
+
+import "noexcept-4_a.H";
+
+int main() {
+  constexpr exception_ptr e;
+  static_assert(e == e);
+  static_assert(noexcept(e == e));
+}