for-in over a qualified set member source fails

• Type: bug (compiler / parser)
• Status: done
• Owner: Track A
• Opened: 2026-06-21
• Relation: next examples/adventure blocker after the text-file surface is made visible; sibling to feature-forin-member-access-source and feature-for-in-iteration.

Symptom

After importing the PAL-backed textfile unit explicitly and compiling adventure with the POSIX platform path, the demo gets past Assign and stops at the save path:

for sp in Player.Spells do
  WriteLn(f, 'spell=' + LowerStr(SpellName(sp)));

pascal26:567: error: for-in: variable is not a string or array ()

Other similar uses exist in the inventory UI:

for sp in g.Player.Spells do ...

Player.Spells is a qualified member-access expression whose type is TSpellSet = set of TSpell.

Root Cause

Set iteration itself is implemented (feature-for-in-iteration), and qualified member-access for-in sources are implemented for arrays/strings (feature-forin-member-access-source). The node-based classifier used for qualified sources still routes only string/array metadata; it does not recover set element metadata for a set-valued field expression.

Direction

• Extend the node-based for-in source classifier to recognize set-valued qualified lvalues (obj.field, Self.field, nested fields).
• Recover the element enum type/range for the field's set type, equivalent to the existing symbol-based SymSetEnumId path for plain set variables.
• Reuse the existing set-membership scan lowering: iterate ordinals and execute the body only when ord in setExpr.
• Keep array/string member-access for-in behavior unchanged.

Acceptance

• A minimal program with for e in obj.SetField do ... over set of <enum> prints members in ordinal order.
• for e in Self.SetField and a nested member source also work, if practical.
• examples/adventure gets past for sp in Player.Spells.
• Existing for-in tests stay green.

Log

• 2026-06-21 - Opened from the adventure compile path. The previous member-access for-in ticket was array/string focused; this covers set-valued qualified sources specifically.
• 2026-06-21 - DONE (Track A). The set membership-scan desugar was extracted from ParseForInSetAST into a reusable BuildForInSetLoop(varIdx, setEnumId, setElemTk, setOperand, bodyNode) that takes an abstract set value node. ParseForInNodeAST (the qualified member-access source path) now recovers the set element enum/range — for an AN_IDENT source from SymSetEnumId/ElemTk, for an AN_FIELD source from two new parallel arrays UFldSetEnumId/ElemTk (captured in AddUField from LastTypeSetEnumId/ElemTk, mirroring the symbol/property paths) — and routes set-valued sources to BuildForInSetLoop over CloneAST(contNode) before the array/string classifier. for sp in g.Player.Spells (nested member access) and for sp in Self.Field both work. Regression test test/test_forin_set_member.pas. make test green; self-host
  • threadsafe fixedpoint byte-identical.

Resolved-in: 085be11 (finalizing commit)