What broke

bug-p-overload-resolution-confuses-an-array-with-its-element-type added a mirror guard to MatchArgRecMismatch: an ARRAY argument does not bind a parameter that is neither an array nor a pointer. That is right for the case it was written for — an array binding a SCALAR parameter, which happened because an array symbol's TypeKind IS its element kind, so a array of Char looked like a Char.

It is wrong for the case the language defines: an array[..] of Char converts to a string.

function Wrap(const q: string): string;
var a: array[0..7] of Char;
begin a := 'hi'; WriteLn(Wrap(a)); end.

pascal26:7: error: no overload of Wrap matches these arguments
  argument types: (Char)
  candidates:
    Wrap(AnsiString)

The diagnostic betrays the model as well as the bug: the array reports as Char, because that is what its symbol's TypeKind holds.

Found by

The Track T watcher, in the full tier at d3c1e87dce5b — pin-shadow.log had been naming it as one of "5 red(s) the current pin does not have" since 70f6a360f475, three commits after the guard landed. The quick gate does not run test_char_array_is_a_string, which is why three of my own gated commits went past it.

Fix

The guard now exempts a char-array argument bound to a string-kind parameter:

not ((MatchArgArrayElemTk[j] = tyChar) and
     (Procs[i].Params[j].TypeKind in [tyString, tyAnsiString, tyShortString,
                                      tyFixedString])) and

MatchArgArrayElemTk is new, filled beside MatchArgArray at the same site, and holds the argument array's ELEMENT kind (which is its symbol's TypeKind). An exemption keyed on the element type rather than on "is a string parameter" generally, so an array of Integer still cannot bind a string parameter — which is the defect the guard exists for.

Verification

• test/test_char_array_is_a_string.pas: 86/86, was refusing to compile.
• The three tests the guard was added for — test_array_and_scalar_overload_binding, test_pointer_to_a_dynamic_array, test_string_typecast_is_a_cast — all still match their fpc-generated .expected byte for byte.
• tools/gate.sh quick GREEN; conformance 346 pass / 0 fail, sets unchanged; fgl 7/7.

Lesson

The guard was added as part of a ticket about ARRAY-vs-SCALAR confusion and was written as "an array does not bind a non-array". Pascal has one standing exception to that and the ticket's rows did not contain it. Varying the shape means varying it against the LANGUAGE, not only against the defect.