Hi Chris,
Am 01.12.25 um 07:47 schrieb Christopher Albert:
Reformatted and minor changes
On Sun, 30 Nov 2025 15:57:51 +0100
Christopher Albert <[email protected]> wrote:
When an array constructor has an explicit type-spec, all elements must
be converted to that type and character elements must be
padded/truncated to the specified length. This was working for simple
cases but failing when:
1. Elements were parenthesized: [integer :: ([1.0])]
2. Constructors were nested: [[integer :: [1.0]]]
3. Character constructors were used with concatenation operators:
[character(16) :: 'a', 'b'] // '|'
4. Nested character constructors with concatenation:
[character(16) :: ['a', 'b']] // '|'
5. Outer constructor without type-spec wrapping inner with type-spec:
[[character(16) :: ['a', 'b']]] // '|'
6. Nested character constructors with different type-specs:
[character(16) :: [character(2) :: 'abcd']]
The root cause was twofold:
First, parenthesized expressions like ([1.0]) create EXPR_OP nodes
that were not being simplified before type conversion in
check_constructor_type(), so type conversion was applied to the
EXPR_OP rather than its contents.
Second, character array constructors with explicit type-spec were not
being resolved before CONCAT operations in eval_intrinsic(), so
elements retained their original lengths instead of being padded to
the type-spec length. Additionally, nested array constructors needed
their type-spec propagated from the outer constructor.
The fix adds:
- Simplification of non-constant expressions in
check_constructor_type() before attempting type conversion
- Call to gfc_check_constructor_type() in eval_intrinsic() to ensure
type-spec conversion happens before any operations on array
constructors
- Character array constructor resolution before CONCAT operations
- Recursive type-spec propagation for nested array constructors.
When a nested array constructor has its own explicit type-spec, it
is resolved first to enforce its own length (truncation/padding)
before propagating the outer type-spec and resolving again.
- Detection of nested character constructors with explicit type-spec
(via length_from_typespec) when the outer constructor has no
type-spec
PR fortran/107721
PR fortran/102417
gcc/fortran/ChangeLog:
* arith.cc (eval_intrinsic): Call gfc_check_constructor_type
on array constructor operands with explicit type-spec to ensure
element type conversion before operations. Resolve character
array constructors before CONCAT operations.
(reduce_binary_ac, reduce_binary_ca, reduce_binary_aa):
Preserve character length info in result arrays.
* array.cc (check_constructor_type): Simplify non-constant
expressions before type checking to handle parenthesized
elements. Handle nested character array constructors with
explicit type-spec when outer constructor has no type-spec.
(gfc_resolve_character_array_constructor): Recursively
propagate type-spec to nested array constructors. If the nested
constructor has an explicit type-spec, resolve it first
before propagating the outer type-spec.
gcc/testsuite/ChangeLog:
* gfortran.dg/array_constructor_typespec_1.f90: New test.
the latest version did miss a closing brace (}) which I added
before pushing as r16-5803-gc50d263beff78a .
Thanks again for the work!
Harald
