typecheck: diagnose missing TYPE OF expressions

docs/ADVANCED_STATIC_TYPING.md

@@ -2,6 +2,20 @@
 
 Claro v1.18.26 adds the first advanced static-typing foundation: typed containers checked by `claro typecheck`.
 
+## Complete `TYPE OF` statements
+
+`TYPE OF` needs an expression, `AS`, and a result name. If the expression is missing, `claro typecheck` gives a repair example instead of silently creating the result variable:
+
+```claro
+TYPE OF AS kind
+```
+
+```text
+TYPE OF needs an expression before AS. Try: TYPE OF score AS kind.
+```
+
+Add the value whose type should be stored, such as `TYPE OF score AS kind`.
+
 Class fields need a type after the field name. If a learner writes `HAS score` instead of `HAS score NUMBER`, `claro typecheck` explains the missing piece:
 
 ```text

docs/CURRENT_STATUS.md

@@ -60,6 +60,7 @@ Ready now:
 - `CHECK TYPE` rejects unknown expected type names with a beginner-facing list of supported types
 - typed function return diagnostics also identify an unknown return expression in compatibility `TAKES` / `LEARNED` functions, matching the modern function and object-method guidance
 - `TYPE OF` reports a direct repair hint when the learner forgets `AS`, for example `TYPE OF score` suggests `TYPE OF score AS kind`
+- `TYPE OF` reports a direct repair hint when the learner forgets the expression before `AS`, for example `TYPE OF AS kind` reports `TYPE OF needs an expression before AS. Try: TYPE OF score AS kind.`
 - `TYPE OF` rejects extra words after its result name with a direct repair hint, so `TYPE OF score AS kind extra` explains that only one result name belongs there; typed `TEACH ... RETURNS TYPE` declarations likewise reject extra words after the return type with a direct repair hint
 - typed `TEACH ... RETURNS` declarations reject a missing return type with a direct repair hint, such as `Function greet needs a return type after RETURNS. Add a type such as NUMBER.` The same diagnostic names the complete class and method, including compatibility `TAKES` / `LEARNED` methods: `Method Player.score needs a return type after RETURNS. Add a type such as NUMBER.`
 - typed list/map checks through `claro typecheck`, including a nested `LIST OF MAP` insertion example

docs/ROADMAP.md

@@ -79,6 +79,7 @@ Keep declared return types honest: `claro typecheck` now reports friendly diagno
 8q.3. Keep `CHECK TYPE` declarations complete: a bare `CHECK TYPE` now explains that the expression, `IS`, and expected type are all required, with a complete repair example.
 8q.4. Keep `CHECK TYPE` declarations ordered: `CHECK TYPE IS NUMBER` now explains that an expression belongs before `IS`, with a complete repair example.
 8q.5. Keep `TYPE OF` declarations understandable: a missing `AS` now gets a direct repair hint with a complete `TYPE OF score AS kind` example.
+8q.5.1. Keep `TYPE OF` declarations complete: a missing expression before `AS` now gets a direct repair hint with a complete `TYPE OF score AS kind` example.
 8q.6. Keep `TYPE OF` declarations unambiguous: extra words after the result name now get a direct repair hint instead of being silently included in the variable name.
 8q.7. Keep typed `TEACH` declarations unambiguous: extra words after a declared return type now get a direct repair hint instead of being treated as part of an unknown type.
 8q.8. Keep typed `TEACH` declarations complete: a bare `RETURNS` now gets a direct repair hint naming the missing type and showing a supported example such as `NUMBER`.

src/claro.c

@@ -652,7 +652,7 @@ else if(!strcmp(up,"IF")){ if(in_teach){ if(nested_blocks<64){ branch_returned[n
   else if(!strcmp(up,"PUT")){ const char *key=find_word_ci(t,"KEY"), *val=find_word_ci(t,"VALUE"); if(key&&val){ char *name=substr(t+3,key); char *expr=xstrdup(trim_inplace((char*)val+5)); char *nt=trim_inplace(name); const char *maptype=type_env_get(types,nt); const char *need=container_member_type(maptype,"MAP"); const char *got=simple_expr_type(types,expr); if(need&&got&&!type_words_match(need,got)){ printf("%s:%d: Type mismatch for map %s: expected %s value, but this value looks like %s.\n",path,line_no,nt,need,got); errs++; } free(name); free(expr); } }
   else if(!strcmp(up,"ASK")){ const char *as=find_word_ci(t,"AS"); char *name=NULL,*type=NULL; if(as){ const char *pcur=as+2; name=unquote_token(&pcur); { char *rest=xstrdup(trim_inplace((char*)pcur)); if(claro_is_type_word(rest)) type=rest; else free(rest); } } else { const char *pcur=t+3; char *prompt=unquote_token(&pcur); free(prompt); name=unquote_token(&pcur); { char *rest=xstrdup(trim_inplace((char*)pcur)); if(claro_is_type_word(rest)) type=rest; else free(rest); } } if(name&&*trim_inplace(name)) type_env_set(&types,trim_inplace(name),type?type:"TEXT"); free(name); free(type); }
   else if(!strcmp(up,"IMPORT")){ const char *as=find_word_ci(t,"AS"); if(as){ const char *pcur=as+2; char *alias=unquote_token(&pcur); if(alias&&*trim_inplace(alias)) type_env_set(&types,trim_inplace(alias),"MODULE"); free(alias); } }
-  else if(!strcmp(up,"TYPE")&&starts_ci(t,"TYPE OF")){ const char *as=find_word_ci(t,"AS"); if(!as){ printf("%s:%d: TYPE OF needs AS. Try: TYPE OF score AS kind.\n",path,line_no); errs++; } else { char *expr=substr(t+7,as); const char *pcur=as+2; char *name=unquote_token(&pcur); char *extra=xstrdup(trim_inplace((char *)pcur)); if(extra&&*extra){ printf("%s:%d: TYPE OF %s has extra text after result name %s. Keep only the expression, AS, and one result name.\n",path,line_no,trim_inplace(expr),trim_inplace(name)); errs++; } else if(name&&*trim_inplace(name)) type_env_set(&types,name,"TEXT"); free(expr); free(name); free(extra); } }
+  else if(!strcmp(up,"TYPE")&&starts_ci(t,"TYPE OF")){ const char *as=find_word_ci(t,"AS"); if(!as){ printf("%s:%d: TYPE OF needs AS. Try: TYPE OF score AS kind.\n",path,line_no); errs++; } else { char *expr=substr(t+7,as); const char *pcur=as+2; char *name=unquote_token(&pcur); char *extra=xstrdup(trim_inplace((char *)pcur)); if(extra&&*extra){ printf("%s:%d: TYPE OF %s has extra text after result name %s. Keep only the expression, AS, and one result name.\n",path,line_no,trim_inplace(expr),trim_inplace(name)); errs++; } else if(!*trim_inplace(expr)){ printf("%s:%d: TYPE OF needs an expression before AS. Try: TYPE OF score AS kind.\n",path,line_no); errs++; } else if(name&&*trim_inplace(name)) type_env_set(&types,name,"TEXT"); free(expr); free(name); free(extra); } }
   else if(!strcmp(up,"NEW")){ const char *as=find_word_ci(t,"AS"); char *name=NULL; char *cls=NULL; char *extra=NULL; char objtype[256]; if(as){ const char *pcur=as+2; cls=substr(t+3,as); name=unquote_token(&pcur); extra=xstrdup(trim_inplace((char *)pcur)); } else { const char *pcur=t+3; cls=unquote_token(&pcur); name=unquote_token(&pcur); extra=xstrdup(trim_inplace((char *)pcur)); } snprintf(objtype,sizeof(objtype),"OBJECT:%s",trim_inplace(cls)); if(name&&*trim_inplace(name)){ TypeFieldCheck *fc; char fullname[256]; char *nt=trim_inplace(name); char *ct=trim_inplace(cls); int duplicate=0,class_known=0,oi,ci; if(extra&&*extra){ printf("%s:%d: NEW %s has extra text after object name %s. Keep only the class and object names.\n",path,line_no,ct,nt); errs++; } for(ci=0;ci<declared_class_count;ci++) if(ci_eq(declared_classes[ci],ct)){ class_known=1; break; } if(declared_class_count>0&&!class_known){ printf("%s:%d: Class %s is not known yet. Check the class name or declare CLASS %s before creating %s.\n",path,line_no,ct,ct,nt); errs++; } for(oi=0;oi<declared_object_count;oi++) if(ci_eq(declared_objects[oi],nt)){ duplicate=1; break; } if(duplicate){ printf("%s:%d: Object %s is created more than once. Give each object a different name.\n",path,line_no,nt); errs++; } else if(declared_object_count<128) snprintf(declared_objects[declared_object_count++],sizeof(declared_objects[0]),"%s",nt); type_env_set(&types,nt,objtype); for(fc=field_checks;fc;fc=fc->next){ if(ci_eq(fc->cls,ct)){ snprintf(fullname,sizeof(fullname),"%s.%s",nt,fc->field); type_env_set(&types,fullname,fc->type); } } } else if(cls&&*trim_inplace(cls)){ printf("%s:%d: NEW %s needs an object name. Add a name after the class, such as NEW %s player.\n",path,line_no,trim_inplace(cls),trim_inplace(cls)); errs++; } else { printf("%s:%d: NEW needs a class name. Add a class and object name, such as NEW Player player.\n",path,line_no); errs++; } free(cls); free(name); free(extra); }
   else if((!strcmp(up,"DO")&&!find_word_ci(t,"TIMES"))||!strcmp(up,"CALL")){ char *fname=NULL; char **parts=NULL; int ac=0,i,is_method=0; char lookup[256],display[256]; if(!strcmp(up,"DO")){ const char *pcur=t+2; fname=unquote_token(&pcur); if(*trim_inplace((char*)pcur)) ac=split_args(pcur,&parts); } else { char *rest=t+4; const char *with=find_word_ci(rest,"WITH"); fname=with?substr(rest,with):xstrdup(rest); if(with&&*trim_inplace((char*)with+4)) ac=split_args(with+4,&parts); } snprintf(lookup,sizeof(lookup),"%s",trim_inplace(fname)); snprintf(display,sizeof(display),"%s",lookup); { char *dot=strchr(lookup,'.'); if(dot){ char objname[128]; const char *objtype; snprintf(objname,sizeof(objname),"%.*s",(int)(dot-lookup),lookup); objtype=type_env_get(types,objname); if(objtype&&starts_ci(objtype,"OBJECT:")){ char method[128]; const char *cls=objtype+7; snprintf(method,sizeof(method),"%s",dot+1); if(!type_method_check_for(method_checks,cls,method)){ printf("%s:%d: Object %s has no method %s. Check the method name or add TEACH %s inside CLASS %s.\n",path,line_no,cls,method,method,cls); errs++; } snprintf(lookup,sizeof(lookup),"%s.%s",cls,method); snprintf(display,sizeof(display),"%s",lookup); is_method=1; }
        else if(!objtype||(!starts_ci(objtype,"MODULE")&&(!strcmp(up,"DO")||type_method_name_exists(method_checks,dot+1)))){ printf("%s:%d: Object %s is not known yet. Create it with NEW ClassName %s before calling %s.\n",path,line_no,objname,objname,lookup); errs++; } } } for(i=0;i<ac;i++){ const char *param=NULL; const char *need=type_param_check_for(param_checks,lookup,i,&param); const char *got=simple_expr_type(types,parts[i]); if(need&&got&&!type_words_match(need,got)){ printf("%s:%d: Type mismatch for %s %s: parameter %s needs %s, but this argument looks like %s.\n",path,line_no,is_method?"method":"function",display,param?param:"argument",need,got); errs++; } } { TypeParamCheck *pc=param_checks; while(pc){ if(ci_eq(pc->func,lookup)&&pc->pos>=ac){ printf("%s:%d: %s %s needs argument %s as %s, but this call does not provide it.\n",path,line_no,is_method?"Method":"Function",display,pc->param,pc->type); errs++; } pc=pc->next; } } { int expected=type_arity_check_for(arity_checks,lookup); if(expected>=0&&ac>expected){ printf("%s:%d: %s %s only accepts %d %s, but this call gives %d. Remove the extra %s.\n",path,line_no,is_method?"Method":"Function",display,expected,expected==1?"argument":"arguments",ac,ac-expected==1?"argument":"arguments"); errs++; } else if(expected>=0&&ac<expected){ int has_checked_missing=0; TypeParamCheck *mpc=param_checks; while(mpc){ if(ci_eq(mpc->func,lookup)&&mpc->pos>=ac){ has_checked_missing=1; break; } mpc=mpc->next; } if(!has_checked_missing){ printf("%s:%d: %s %s needs %d %s, but this call gives %d. Add the missing %s.\n",path,line_no,is_method?"Method":"Function",display,expected,expected==1?"argument":"arguments",ac,expected-ac==1?"argument":"arguments"); errs++; } } else if((!strcmp(up,"DO")||!strcmp(up,"CALL"))&&!is_method&&!strchr(lookup,'.')&&expected<0){ printf("%s:%d: Function %s is not known yet. Check the function name or add TEACH %s before calling it.\n",path,line_no,lookup,lookup); errs++; } } free(fname); }

tests/test_validate_typecheck_diagnostics.py

@@ -89,6 +89,12 @@ class ValidateTypecheckDiagnosticsTests(unittest.TestCase):
             MODULE.EXPECTED,
         )
 
+    def test_includes_missing_type_of_expression_fixture(self):
+        self.assertIn(
+            "tests/typecheck_missing_type_of_expression_bad.claro",
+            MODULE.EXPECTED,
+        )
+
     def test_includes_lowercase_compatibility_return_success_fixture(self):
         self.assertIn(
             "tests/typecheck_function_lowercase_return_good.claro",

tests/typecheck_missing_type_of_expression_bad.claro

@@ -0,0 +1 @@
+TYPE OF AS kind

tools/validate_typecheck_diagnostics.py

@@ -7,6 +7,9 @@ ROOT = Path(__file__).resolve().parents[1]
 EXE = ROOT / ("claro.exe" if os.name == "nt" else "claro")
 
 EXPECTED = {
+    "tests/typecheck_missing_type_of_expression_bad.claro": [
+        "tests/typecheck_missing_type_of_expression_bad.claro:1: TYPE OF needs an expression before AS. Try: TYPE OF score AS kind.",
+    ],
     "tests/typecheck_function_duplicate_param_bad.claro": [
         "tests/typecheck_function_duplicate_param_bad.claro:1: Function greet declares parameter name more than once. Give each parameter a different name.",
     ],