[PATCH] Fortran: fix checking of renamed-on-use interface name [PR120784]

[Harald Anlauf]

Dear all,

here's an obvious fix for a rejects-valid when an interface was
renamed on use and is extended in the importing module.  One check
incorrectly referred to the original interface name, not the
renamed one.

Regtested on x86_64-pc-linux-gnu.  OK for mainline / backports?

Thanks,
Harald


From 69c64f3e21b9702d19a833534f2f8621845b5c98 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anl...@gmx.de>
Date: Mon, 23 Jun 2025 21:33:40 +0200
Subject: [PATCH] Fortran: fix checking of renamed-on-use interface name
 [PR120784]

	PR fortran/120784

gcc/fortran/ChangeLog:

	* interface.cc (gfc_match_end_interface): If a use-associated
	symbol is renamed, use the local_name for checking.

gcc/testsuite/ChangeLog:

	* gfortran.dg/interface_63.f90: New test.
---
 gcc/fortran/interface.cc                   | 13 +++--
 gcc/testsuite/gfortran.dg/interface_63.f90 | 62 ++++++++++++++++++++++
 2 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/interface_63.f90

diff --git a/gcc/fortran/interface.cc b/gcc/fortran/interface.cc
index b8542920ce7..cdb838d8336 100644
--- a/gcc/fortran/interface.cc
+++ b/gcc/fortran/interface.cc
@@ -452,11 +452,18 @@ gfc_match_end_interface (void)
 
     case INTERFACE_DTIO:
     case INTERFACE_GENERIC:
+      /* If a use-associated symbol is renamed, check the local_name.   */
+      const char *local_name = current_interface.sym->name;
+
+      if (current_interface.sym->attr.use_assoc
+	  && current_interface.sym->attr.use_rename
+	  && current_interface.sym->ns->use_stmts->rename)
+	local_name = current_interface.sym->ns->use_stmts->rename->local_name;
+
       if (type != current_interface.type
-	  || strcmp (current_interface.sym->name, name) != 0)
+	  || strcmp (local_name, name) != 0)
 	{
-	  gfc_error ("Expecting %<END INTERFACE %s%> at %C",
-		     current_interface.sym->name);
+	  gfc_error ("Expecting %<END INTERFACE %s%> at %C", local_name);
 	  m = MATCH_ERROR;
 	}
 
diff --git a/gcc/testsuite/gfortran.dg/interface_63.f90 b/gcc/testsuite/gfortran.dg/interface_63.f90
new file mode 100644
index 00000000000..a55e8ab431b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/interface_63.f90
@@ -0,0 +1,62 @@
+! { dg-do compile }
+! PR fortran/120784 - fix checking of renamed-on-use interface name
+!
+! Contributed by Matt Thompson  <matthew.thompson at nasa dot gov>
+
+module A_mod
+  implicit none
+
+  interface Get
+     procedure :: get_1
+     procedure :: get_2
+  end interface Get
+
+contains
+
+  subroutine get_1(i)
+    integer :: i
+    i = 5
+  end subroutine get_1
+
+  subroutine get_2(x)
+    real :: x
+    x = 4
+  end subroutine get_2
+end module A_mod
+
+module B_mod
+  use A_mod, only : MyGet => Get
+  implicit none
+
+  interface MyGet
+     procedure :: other_get
+  end interface MyGet
+
+contains
+
+  subroutine other_get(c)
+    character(1) :: c
+    c = 'a'
+  end subroutine other_get
+
+  subroutine check_get ()
+    character :: c
+    integer   :: i
+    real      :: r
+    call myget (c)
+    call myget (i)
+    call myget (r)
+  end subroutine check_get
+
+end module B_MOD
+
+program p
+  use b_mod, only: myget
+  implicit none
+  character :: c
+  integer   :: i
+  real      :: r
+  call myget (c)
+  call myget (i)
+  call myget (r)
+end
-- 
2.43.0