I plan to commit the attached patch shortly to close this out.
Regression tests OK
Thanks for comments all.
Regards
Jerry
---
fortran: Diagnose invalid array initializer after parameter
substitution [PR103367]
Keep the trunk fallback from r16-8509, but turn it into a real
constant-expression error instead of silently returning an empty
constructor. This avoids the ICE from PR103367 without regressing
the more specific diagnostics discussed in the Bugzilla follow-up.
PR fortran/103367
gcc/fortran/ChangeLog:
* trans-array.cc (gfc_conv_array_initializer): Emit an error for
invalid residual initializer expressions before returning a safe
empty constructor.
gcc/testsuite/ChangeLog:
* gfortran.dg/pr103367.f90: Expect a constant-expression error and
prune the legacy-extension warning.
Signed-off-by: Christopher Albert <[email protected]>From 7e53117e487fac5a1d4f209b40070921ae8a0416 Mon Sep 17 00:00:00 2001
From: Christopher Albert <[email protected]>
Date: Wed, 8 Apr 2026 22:37:11 +0200
Subject: [PATCH] fortran: Diagnose invalid array initializer after parameter
substitution [PR103367]
Keep the trunk fallback from r16-8509, but turn it into a real
constant-expression error instead of silently returning an empty
constructor. This avoids the ICE from PR103367 without regressing
the more specific diagnostics discussed in the Bugzilla follow-up.
PR fortran/103367
gcc/fortran/ChangeLog:
* trans-array.cc (gfc_conv_array_initializer): Emit an error for
invalid residual initializer expressions before returning a safe
empty constructor.
gcc/testsuite/ChangeLog:
* gfortran.dg/pr103367.f90: Expect a constant-expression error and
prune the legacy-extension warning.
Signed-off-by: Christopher Albert <[email protected]>
---
gcc/fortran/trans-array.cc | 10 +++++++---
gcc/testsuite/gfortran.dg/pr103367.f90 | 7 ++++---
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index ed299c8b21b..b57c18aba00 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -7099,13 +7099,17 @@ gfc_conv_array_initializer (tree type, gfc_expr * expr)
expr = expr->symtree->n.sym->value;
/* After parameter substitution the expression should be a constant, array
- constructor, structure constructor, or NULL. Anything else means the
- frontend already diagnosed an error; return a zero-filled array. */
+ constructor, structure constructor, or NULL. Anything else is invalid
+ and must not ICE later in lowering. */
if (expr->expr_type != EXPR_CONSTANT
&& expr->expr_type != EXPR_STRUCTURE
&& expr->expr_type != EXPR_ARRAY
&& expr->expr_type != EXPR_NULL)
- return build_constructor (type, NULL);
+ {
+ gfc_error ("Array initializer at %L does not reduce to a constant "
+ "expression", &expr->where);
+ return build_constructor (type, NULL);
+ }
switch (expr->expr_type)
{
diff --git a/gcc/testsuite/gfortran.dg/pr103367.f90 b/gcc/testsuite/gfortran.dg/pr103367.f90
index c4c860c65ff..e7c89b41a7c 100644
--- a/gcc/testsuite/gfortran.dg/pr103367.f90
+++ b/gcc/testsuite/gfortran.dg/pr103367.f90
@@ -1,14 +1,15 @@
! { dg-do compile }
!
! PR fortran/103367
-! An undefined variable in a parameter array initializer reached
-! gfc_conv_array_initializer and hit gcc_unreachable().
+! Invalid initialization expressions must not ICE if they survive
+! semantic checking and reach array initializer lowering.
program p
type t
integer :: a(1,2) = 3
end type
type(t), parameter :: x(1) = t(4)
- integer :: y(1,2) = (x(b)%a) ! { dg-warning "Legacy Extension" }
+ integer :: y(1,2) = (x(b)%a) ! { dg-error "does not reduce to a constant expression" }
print *, y
end
+! { dg-prune-output "Legacy Extension: REAL array index" }
--
2.53.0
