typecheck: clarify arithmetic return mismatches

docs/ROADMAP.md

@@ -39,7 +39,7 @@ See `CURRENT_STATUS.md` for the detailed feature matrix.
 6. Continue narrowing expression diagnostics: known TEXT operands now remain visible through arithmetic, with focused numeric-subtraction, numeric-division, and numeric-multiplication positives plus text-operand addition, subtraction, multiplication, and division coverage. Text concatenation into TEXT fields is covered in both operand orders, including field-to-field concatenation. Each numeric operator gives specific guidance naming the text operand. `CHECK TYPE` also rejects misspelled expected type names before comparing values.
 - Keep IDE metadata aligned with the current beginner syntax: typed-language keywords such as `RETURNS`, `CHECK`, and `TYPE` are now included in the metadata used by editor helpers.
 - Keep compatibility-call coverage aligned with modern calls: empty `CALL object.method WITH` forms now have a focused missing-argument diagnostic fixture alongside the modern `DO object.method` case.
-Keep declared return types honest: `claro typecheck` now reports friendly diagnostics for unknown declared return types, mismatched, not-yet-inferable, and empty return expressions, declarations with no `RETURN`, and incomplete conditional branches, when a simple function or object method declares `RETURNS TYPE`; the declaration keyword is case-insensitive like other Claro keywords, with positive coverage in modern and compatibility function forms, including lowercase compatibility declarations and lowercase compatibility method declarations, plus a lowercase compatibility-method mismatch fixture. Complete `IF`/`ELSE` return branches, including nested complete conditionals in functions and methods, are accepted, and modern and compatibility function syntax plus compatibility method syntax are covered by focused fixtures. `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including object methods; typed methods can also return class-declared fields by simple name, with positive and mismatch fixtures, and unknown method return expressions now have dedicated modern and compatibility diagnostic fixtures. Full path-sensitive analysis across nested conditionals and loops remains planned.
+Keep declared return types honest: `claro typecheck` now reports friendly diagnostics for unknown declared return types, mismatched, not-yet-inferable, and empty return expressions, declarations with no `RETURN`, and incomplete conditional branches, when a simple function or object method declares `RETURNS TYPE`; the declaration keyword is case-insensitive like other Claro keywords, with positive coverage in modern and compatibility function forms, including lowercase compatibility declarations and lowercase compatibility method declarations, plus a lowercase compatibility-method mismatch fixture. Complete `IF`/`ELSE` return branches, including nested complete conditionals in functions and methods, are accepted, and modern and compatibility function syntax plus compatibility method syntax are covered by focused fixtures. `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including object methods; typed methods can also return class-declared fields by simple name, with positive and mismatch fixtures, and unknown method return expressions now have dedicated modern and compatibility diagnostic fixtures, and NUMBER return expressions with known TEXT arithmetic operands identify the operation and offending operand. Full path-sensitive analysis across nested conditionals and loops remains planned.
 
 ## Complete-platform milestones