typecheck: diagnose unknown method fields

docs/ADVANCED_STATIC_TYPING.md

@@ -56,6 +56,28 @@ ADD person TO people
 
 This is accepted with `Type check OK`. More complex nested container operations and full key/value inference remain future work.
 
+## Unknown fields inside methods
+
+When a method assigns a known value to a bare name that is not a parameter, local variable, or declared class field, `claro typecheck` reports the missing field instead of silently treating the typo as a new variable:
+
+```claro
+CLASS Player
+    HAS score NUMBER
+
+    TEACH train
+        SET level 3
+    END
+END
+```
+
+The diagnostic is:
+
+```text
+Object Player has no field level. Check the field name or add HAS level NUMBER to the class.
+```
+
+This narrow check covers direct method assignments with a known expression. Broader local-variable and control-flow analysis remains future work.
+
 ## Complete conditional returns
 
 ### Return expressions that need more information

docs/CURRENT_STATUS.md

@@ -55,7 +55,7 @@ Ready now:
 - typed list/map checks through `claro typecheck`, including a nested `LIST OF MAP` insertion example
 - simple function and object-method return checks with `TEACH name ... RETURNS TYPE`, including learner-facing diagnostics for unknown declared return types, mismatched or not-yet-inferable `RETURN` expressions (including method-specific diagnostics naming the class and method, with modern and compatibility method coverage), empty `RETURN` statements, declarations that contain no `RETURN`, and declarations whose only return is inside an incomplete conditional; `RETURNS` is case-insensitive like other Claro keywords and has positive coverage in both modern and compatibility function forms, including lowercase compatibility declarations and lowercase compatibility method declarations, plus a lowercase compatibility-method mismatch diagnostic; `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including method return expressions; positive function-return coverage includes numeric multiplication; compatibility methods now have dedicated positive numeric addition, subtraction, division, and multiplication return fixtures plus compatibility addition, subtraction, division, and multiplication diagnostic fixtures; NUMBER return diagnostics name a known TEXT operand and arithmetic operation instead of hiding the cause behind a generic mismatch, with focused addition, subtraction, multiplication, and division coverage for functions and methods; typed methods can also return class-declared fields by simple name, with positive and mismatch coverage
 - 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 and simple object methods in both modern `DO` and compatibility `CALL ... WITH` forms, treat empty compatibility calls such as `CALL greet WITH` and `CALL player.rename WITH` as missing-argument mistakes, 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 modern plus compatibility calls to undeclared object 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, explicitly typed field assignments, dedicated positive NUMBER/TEXT/YESNO `CHECK TYPE` metadata fixtures, simple and chained object aliases for both field assignments and `CHECK TYPE` metadata (including a chained TEXT-field check), aliased object-method calls including chained aliases in modern `DO` and compatibility `CALL ... WITH` forms (with a dedicated positive modern `DO` chained-alias fixture), field-to-field, compound arithmetic field expressions, and arithmetic/text expression result types, 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 including explicitly typed assignments, numeric and text results from simple arithmetic/text expressions in object-field assignments, plus method-body field assignment and `CHECK TYPE` diagnostics for NUMBER, TEXT, and YESNO fields in modern and compatibility syntax, including compatibility YESNO `CHECK TYPE` metadata coverage, and a plain beginner-facing unknown-field diagnostic when the assigned expression type is not inferable yet
+- 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, explicitly typed field assignments, dedicated positive NUMBER/TEXT/YESNO `CHECK TYPE` metadata fixtures, simple and chained object aliases for both field assignments and `CHECK TYPE` metadata (including a chained TEXT-field check), aliased object-method calls including chained aliases in modern `DO` and compatibility `CALL ... WITH` forms (with a dedicated positive modern `DO` chained-alias fixture), field-to-field, compound arithmetic field expressions, and arithmetic/text expression result types, 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 including explicitly typed assignments, numeric and text results from simple arithmetic/text expressions in object-field assignments, plus method-body field assignment and `CHECK TYPE` diagnostics for NUMBER, TEXT, and YESNO fields in modern and compatibility syntax, including compatibility YESNO `CHECK TYPE` metadata coverage, direct method assignments to undeclared fields now produce a beginner-facing missing-field diagnostic when the assigned expression has a known type, and a plain beginner-facing unknown-field diagnostic when the assigned expression is not inferable yet
 
 
 Still needed:

docs/ROADMAP.md

@@ -43,7 +43,7 @@ See `CURRENT_STATUS.md` for the detailed feature matrix.
 - 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; positive numeric multiplication return coverage now sits beside the mismatch fixtures, including a dedicated compatibility-method multiplication success fixture; 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, including focused addition, subtraction, multiplication, and division coverage for functions and methods. Compatibility method subtraction diagnostics are also covered alongside the existing addition diagnostic. Full path-sensitive analysis across nested conditionals and loops remains planned.
 
-7. Keep method-body field diagnostics learner-facing: typed methods now name the class method when a simple class field receives a known mismatch in `CHECK TYPE` or assignment, or a known TEXT operand in a NUMBER expression, with matching text and numeric coverage in modern and compatibility method syntax; broader control-flow and object-flow analysis remains planned.
+7. Keep method-body field diagnostics learner-facing: typed methods now name the class method when a simple class field receives a known mismatch in `CHECK TYPE` or assignment, or a known TEXT operand in a NUMBER expression, with matching text and numeric coverage in modern and compatibility method syntax; direct assignments to undeclared method fields now report the missing field when the value type is known; broader control-flow and object-flow analysis remains planned.
 8. Keep method-body coverage balanced across beginner field types and syntax generations: YESNO field assignment mismatches are now validated for both modern `DO` and compatibility `CALL ... WITH` method syntax, method-body `CHECK TYPE` metadata mismatches now have matching compatibility `TAKES` / `LEARNED` coverage alongside the modern form, and compatibility YESNO field metadata has dedicated positive and negative fixtures.
 
 ### 1. Strong static types

tests/typecheck_method_unknown_field_bad.claro

@@ -0,0 +1,10 @@
+CLASS Player
+    HAS score NUMBER
+
+    TEACH train
+        SET level 3
+    END
+END
+
+NEW Player player
+DO player.train

tools/validate_typecheck_diagnostics.py

@@ -275,6 +275,9 @@ EXPECTED = {
     "tests/typecheck_method_field_assignment_bad.claro": [
         "tests/typecheck_method_field_assignment_bad.claro:5: Type mismatch for field score in Player.add: addition needs NUMBER values, but name looks like TEXT.",
     ],
+    "tests/typecheck_method_unknown_field_bad.claro": [
+        "tests/typecheck_method_unknown_field_bad.claro:5: Object Player has no field level. Check the field name or add HAS level NUMBER to the class.",
+    ],
     "tests/typecheck_method_text_field_assignment_bad.claro": [
         "tests/typecheck_method_text_field_assignment_bad.claro:4: Type mismatch for field name in Player.rename: expected TEXT, but this value looks like NUMBER.",
     ],