typecheck: diagnose missing unchecked function args

docs/ADVANCED_STATIC_TYPING.md

@@ -339,6 +339,12 @@ Both sides of this narrow field foundation are covered by validation: `tests/typ
 
 This slice is intentionally small: it covers direct `NEW Class object` plus `SET object.field value` cases in one file. Field declarations are collected even when a learner writes a simple method before a later `HAS` field, so the type checker can still report the field's declared type. Broader object flows, aliases, method return checks, and richer object signatures remain future work.
 
+Simple functions also get an arity check before running. If a learner defines `TEACH greet name` and then writes `DO greet` without the `name` argument, `claro typecheck` reports:
+
+```text
+Function greet needs 1 argument, but this call gives 0. Add the missing argument.
+```
+
 ## Status
 
 This is currently a static checker feature. It improves `claro typecheck` and validation confidence for `DO` and compatibility `CALL ... WITH` function calls, simple `DO object.method ...` calls where the object was created with `NEW Class name`, and direct assignments to known object fields. Runtime enforcement for every container mutation and richer function/object signatures can be added later after the syntax is classroom-tested.

docs/CURRENT_STATUS.md

@@ -52,7 +52,7 @@ Ready now:
 - typed variables such as `SET score NUMBER 10`
 - `TYPE OF` and `CHECK TYPE`
 - typed list/map checks through `claro typecheck`
-- a narrow function/method argument check: `CHECK TYPE parameter IS TYPE` inside a function or simple object method lets `claro typecheck` accept correct checked calls, catch mismatched `DO`, `CALL ... WITH`, `DO object.method ...`, and compatibility `CALL object.method WITH ...` arguments, including checked methods that appear after another method in the same class, report missing checked function and method arguments, catch extra arguments to simple functions and checked methods even when the checked method appears after another method in the same class, catch modern `DO` and compatibility `CALL ... WITH` calls to undeclared simple functions, explain when `DO object.method ...` or compatibility `CALL object.method WITH ...` happens before the object is created with `NEW` even if the method name is also wrong, and catch simple calls to undeclared methods with a class-specific `TEACH` hint
+- a narrow function/method argument check: `CHECK TYPE parameter IS TYPE` inside a function or simple object method lets `claro typecheck` accept correct checked calls, catch mismatched `DO`, `CALL ... WITH`, `DO object.method ...`, and compatibility `CALL object.method WITH ...` arguments, including checked methods that appear after another method in the same class, report missing checked function and method arguments, report missing unchecked arguments for simple functions, catch extra arguments to simple functions and checked methods even when the checked method appears after another method in the same class, catch modern `DO` and compatibility `CALL ... WITH` calls to undeclared simple functions, explain when `DO object.method ...` or compatibility `CALL object.method WITH ...` happens before the object is created with `NEW` even if the method name is also wrong, and catch simple calls to undeclared methods with a class-specific `TEACH` hint
 - a narrow object-field assignment/check-type check for simple `NEW Class object` plus direct `SET object.field value` and `CHECK TYPE object.field IS TYPE` cases when the class declares `HAS field TYPE`; validation now covers correct NUMBER, TEXT, and YESNO direct assignments, direct `CHECK TYPE` metadata acceptance for NUMBER/TEXT/YESNO fields, negative NUMBER/TEXT/YESNO field `CHECK TYPE` metadata mismatches, NUMBER/TEXT/YESNO-expectation unknown-field `CHECK TYPE` diagnostics, missing-object field assignment and `CHECK TYPE` diagnostics, NUMBER/TEXT/YESNO wrong-type diagnostics, field collection when a `HAS` field appears after a simple method, NUMBER/TEXT/YESNO-valued unknown-field diagnostics for direct assignments to undeclared fields, plus a plain beginner-facing unknown-field diagnostic when the assigned expression type is not inferable yet
 
 Still needed:

docs/ROADMAP.md

@@ -31,7 +31,7 @@ See `CURRENT_STATUS.md` for the detailed feature matrix.
 
 1. Keep beginner-facing docs current and separate from historical release notes.
 2. Keep examples aligned with the modern simple syntax (`END`, `DO`, short `SET`, short `ASK`) while documenting older compatibility forms separately.
-3. Expand validation around typecheck diagnostics and package/networking safety. Current Forgejo/Gitea CI runs the documented release gates (`claro validate`, typecheck diagnostics validation, version convention validation, and CI workflow coverage validation). Current package safety validation covers safe manifest/lockfile creation, rejecting unsafe package names during `package add`, detecting unsafe package names already present in `claro.project` during `package doctor`, refusing to write lockfile data for unsafe package names during `package lock`, and making `package remove` fail instead of reporting success when unsafe package names remain during lockfile refresh. Current function validation covers correct checked calls, wrong-type arguments, missing checked-argument diagnostics, extra-argument diagnostics, and beginner-facing unknown-function diagnostics for mistyped modern `DO` and compatibility `CALL ... WITH` calls; current object-method parameter validation covers correct modern `DO object.method ...` and compatibility `CALL object.method WITH ...` checked calls, wrong-type diagnostics for both call forms, checked methods after another method in the same class, missing and extra checked-argument diagnostics including the extra-argument case for a checked method after another method in the same class, missing-object guidance when `DO player.method ...` or compatibility `CALL object.method WITH ...` appears before `NEW` even if the method name is also wrong, and a class-specific unknown-method diagnostic when a learner calls a method the class does not declare; object-field validation covers correct NUMBER, TEXT, and YESNO direct `SET object.field value` assignments, direct `CHECK TYPE` metadata acceptance for NUMBER/TEXT/YESNO fields, negative NUMBER/TEXT/YESNO metadata mismatches, NUMBER/TEXT/YESNO-expectation unknown-field `CHECK TYPE` diagnostics, missing-object field assignment and `CHECK TYPE` diagnostics, NUMBER/TEXT/YESNO wrong-type direct assignments, field collection when `HAS` appears after a simple method, NUMBER/TEXT/YESNO-valued unknown-field direct assignments, plus a plain beginner-facing unknown-field diagnostic when the assigned expression type is not inferable yet.
+3. Expand validation around typecheck diagnostics and package/networking safety. Current Forgejo/Gitea CI runs the documented release gates (`claro validate`, typecheck diagnostics validation, version convention validation, and CI workflow coverage validation). Current package safety validation covers safe manifest/lockfile creation, rejecting unsafe package names during `package add`, detecting unsafe package names already present in `claro.project` during `package doctor`, refusing to write lockfile data for unsafe package names during `package lock`, and making `package remove` fail instead of reporting success when unsafe package names remain during lockfile refresh. Current function validation covers correct checked calls, wrong-type arguments, missing checked-argument diagnostics, missing unchecked-argument diagnostics for simple functions, extra-argument diagnostics, and beginner-facing unknown-function diagnostics for mistyped modern `DO` and compatibility `CALL ... WITH` calls; current object-method parameter validation covers correct modern `DO object.method ...` and compatibility `CALL object.method WITH ...` checked calls, wrong-type diagnostics for both call forms, checked methods after another method in the same class, missing and extra checked-argument diagnostics including the extra-argument case for a checked method after another method in the same class, missing-object guidance when `DO player.method ...` or compatibility `CALL object.method WITH ...` appears before `NEW` even if the method name is also wrong, and a class-specific unknown-method diagnostic when a learner calls a method the class does not declare; object-field validation covers correct NUMBER, TEXT, and YESNO direct `SET object.field value` assignments, direct `CHECK TYPE` metadata acceptance for NUMBER/TEXT/YESNO fields, negative NUMBER/TEXT/YESNO metadata mismatches, NUMBER/TEXT/YESNO-expectation unknown-field `CHECK TYPE` diagnostics, missing-object field assignment and `CHECK TYPE` diagnostics, NUMBER/TEXT/YESNO wrong-type direct assignments, field collection when a `HAS` field appears after a simple method, NUMBER/TEXT/YESNO-valued unknown-field diagnostics, and a beginner-facing unknown-field diagnostic when an undeclared field assignment uses an expression whose type is not inferable yet.
 4. Add small examples for each foundation feature before adding bigger syntax.
 
 ## Complete-platform milestones