[gcc r11-10501] Fortran: fix ICE in check_charlen_present [PR108420]

[gcc r11-10501] Fortran: fix ICE in check_charlen_present [PR108420]

[Harald Anlauf]

https://gcc.gnu.org/g:c3985fd624053502b0aad85132982b4f8970811a

commit r11-10501-gc3985fd624053502b0aad85132982b4f8970811a
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Mon Jan 16 21:41:09 2023 +0100

    Fortran: fix ICE in check_charlen_present [PR108420]
    
    gcc/fortran/ChangeLog:
    
            PR fortran/108420
            * iresolve.c (check_charlen_present): Preserve character length if
            there is no array constructor.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/108420
            * gfortran.dg/pr108420.f90: New test.
    
    (cherry picked from commit e6669c0a50ed8aee9e5997d61e6271668d149218)

Diff:
---
 gcc/fortran/iresolve.c                 |  9 ++++++---
 gcc/testsuite/gfortran.dg/pr108420.f90 | 10 ++++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/gcc/fortran/iresolve.c b/gcc/fortran/iresolve.c
index 598c0409b66..03db23b5b45 100644
--- a/gcc/fortran/iresolve.c
+++ b/gcc/fortran/iresolve.c
@@ -94,9 +94,12 @@ check_charlen_present (gfc_expr *source)
   else if (source->expr_type == EXPR_ARRAY)
     {
       gfc_constructor *c = gfc_constructor_first (source->value.constructor);
-      source->ts.u.cl->length
-		= gfc_get_int_expr (gfc_charlen_int_kind, NULL,
-				    c->expr->value.character.length);
+      if (c)
+	source->ts.u.cl->length
+	  = gfc_get_int_expr (gfc_charlen_int_kind, NULL,
+			      c->expr->value.character.length);
+      if (source->ts.u.cl->length == NULL)
+	gfc_internal_error ("check_charlen_present(): length not set");
     }
 }
 
diff --git a/gcc/testsuite/gfortran.dg/pr108420.f90 b/gcc/testsuite/gfortran.dg/pr108420.f90
new file mode 100644
index 00000000000..985c0b3bf53
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr108420.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! PR fortran/108420
+! Contributed by G.Steinmetz
+
+program p
+  character :: c = 'c'
+  logical   :: m = .true.
+  print *, merge(transfer('a', 'b', 0), c, .true.)
+  print *, merge(transfer('a', 'b', 0), c, m)
+end