[PATCH, committed] Fortran: error recovery for bad deferred character length assignment [PR104314]

[Harald Anlauf <anlauf@gmx.de>]

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Dear all,

the attached obvious patch fixes an ICE on a NULL pointer
dereference.  We didn't properly check that the types of
expressions are character before referencing the length.

The issue was originally investigated by Steve, so I made
him co-author.

Regtested on x86_64-pc-linux-gnu and pushed to mainline as
commit r13-2690-g7bd4deb2a7c1394550610ab27507d1ed2af817c2

Thanks,
Harald


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From 7bd4deb2a7c1394550610ab27507d1ed2af817c2 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Thu, 15 Sep 2022 22:06:53 +0200
Subject: [PATCH] Fortran: error recovery for bad deferred character length
 assignment [PR104314]

gcc/fortran/ChangeLog:

	PR fortran/104314
	* resolve.cc (deferred_op_assign): Do not try to generate temporary
	for deferred character length assignment if types do not agree.

gcc/testsuite/ChangeLog:

	PR fortran/104314
	* gfortran.dg/pr104314.f90: New test.

Co-authored-by: Steven G. Kargl <kargl@gcc.gnu.org>
---
 gcc/fortran/resolve.cc                 | 1 +
 gcc/testsuite/gfortran.dg/pr104314.f90 | 9 +++++++++
 2 files changed, 10 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/pr104314.f90

diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc
index ca114750f65..ae7ebb624e4 100644
--- a/gcc/fortran/resolve.cc
+++ b/gcc/fortran/resolve.cc
@@ -11803,6 +11803,7 @@ deferred_op_assign (gfc_code **code, gfc_namespace *ns)

   if (!((*code)->expr1->ts.type == BT_CHARACTER
 	 && (*code)->expr1->ts.deferred && (*code)->expr1->rank
+	 && (*code)->expr2->ts.type == BT_CHARACTER
 	 && (*code)->expr2->expr_type == EXPR_OP))
     return false;

diff --git a/gcc/testsuite/gfortran.dg/pr104314.f90 b/gcc/testsuite/gfortran.dg/pr104314.f90
new file mode 100644
index 00000000000..510ded0b164
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr104314.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! PR fortran/104314 - ICE in deferred_op_assign
+! Contributed by G.Steinmetz
+
+program p
+  character(:), allocatable :: c(:)
+  c = ['123']
+  c = c == c  ! { dg-error "Cannot convert" }
+end
--
2.35.3