typecheck: validate aliased object fields

README.md

@@ -215,6 +215,18 @@ It also catches direct assignments to undeclared fields and suggests the matchin
 Object Player has no field level. Check the field name or add HAS level NUMBER to the class.
 ```
 
+The same field check follows a simple object alias. After `SET alias player`, assignments through `alias.score` still use the field type declared by `Player`:
+
+```claro
+NEW Player player
+SET alias player
+SET alias.score "ten"
+```
+
+```text
+Type mismatch for field alias.score: expected NUMBER, but this value looks like TEXT.
+```
+
 The same check follows simple arithmetic and text-concatenation expressions. For example, `SET player.score player.name + 1` reports that the value looks like `TEXT`, rather than silently accepting an expression whose result cannot fit the `NUMBER` field.
 
 TEXT-valued and YESNO-valued field-name mistakes are validated too:

docs/ADVANCED_STATIC_TYPING.md

@@ -56,6 +56,24 @@ ADD person TO people
 
 This is accepted with `Type check OK`. More complex nested container operations and full key/value inference remain future work.
 
+## Object aliases and field checks
+
+When a simple object is assigned to another variable, `claro typecheck` preserves its class for direct field assignments:
+
+```claro
+NEW Player player
+SET alias player
+SET alias.score 10
+```
+
+If the value has the wrong type, the diagnostic names the alias and the expected class field type:
+
+```text
+Type mismatch for field alias.score: expected NUMBER, but this value looks like TEXT.
+```
+
+This is intentionally limited to simple aliases. Broader object-flow analysis through branches, loops, and complex expressions remains planned.
+
 ## Function parameter checks
 
 Claro now has a small static-checking foundation for function arguments. Keep the beginner-friendly function syntax, then put the expected type inside the function with `CHECK TYPE`:

docs/CURRENT_STATUS.md

@@ -53,7 +53,7 @@ Ready now:
 - `TYPE OF` and `CHECK TYPE`
 - typed list/map checks through `claro typecheck`, including a nested `LIST OF MAP` insertion example
 - 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, treat empty compatibility calls such as `CALL greet 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, field-to-field, compound arithmetic field expressions, and arithmetic/text expression result types, 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, numeric and text results from simple arithmetic/text expressions in object-field assignments, plus 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, simple object aliases, field-to-field, compound arithmetic field expressions, and arithmetic/text expression result types, 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, numeric and text results from simple arithmetic/text expressions in object-field assignments, plus a plain beginner-facing unknown-field diagnostic when the assigned expression type is not inferable yet
 
 Still needed:
 - richer typed function signatures and return values

docs/ROADMAP.md

@@ -34,7 +34,7 @@ See `CURRENT_STATUS.md` for the detailed feature matrix.
 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, package security validation, and CI workflow coverage validation). Current package safety validation covers safe project creation, rejecting unsafe project names during `claro new`, 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`, making `package list` fail instead of displaying unsafe package entries as normal package names, making `package init` fail instead of reporting the project ready when unsafe package names are already present, making `package add` fail before changing files when unsafe package names are already present, making `package remove` fail instead of reporting success when unsafe package names remain during lockfile refresh, allowing `package remove` to remove an exact unsafe package entry so learners can repair a bad `claro.project`, making `package doctor` reject stale lockfile checksums for listed packages, and making `package doctor` reject lockfile package entries that are not listed in `claro.project`. Current function validation covers correct checked calls, wrong-type arguments, missing checked-argument diagnostics, missing unchecked-argument diagnostics for simple functions in both modern `DO greet` and empty compatibility `CALL greet WITH` forms, 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 unchecked-argument diagnostics for simple object methods, 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 class-specific unknown-method diagnostics for both modern and compatibility calls when a learner calls a method the class does not declare; current object-field validation covers direct NUMBER/TEXT/YESNO field-assignment positives, direct object-field `CHECK TYPE` metadata positives for NUMBER/TEXT/YESNO fields, negative NUMBER/TEXT/YESNO field metadata mismatches, NUMBER/TEXT/YESNO-expectation unknown-field `CHECK TYPE` diagnostics, direct wrong-type field assignment diagnostics, field collection when a `HAS` field appears after a simple method, direct unknown-field diagnostics for NUMBER/TEXT/YESNO values, a beginner-facing fallback for unknown fields assigned from expressions whose type is not inferable yet, and missing-object diagnostics for both `SET object.field value` and `CHECK TYPE object.field IS TYPE` before `NEW`.
 3a. Keep package diagnostics actionable: invalid package manifest format fields now name the file and explain how to repair it, separately from an absent manifest. Keep package validation honest by checking that the project manifest has one non-empty project name, that the project and each listed package manifest declare the exact supported manifest version, package version, local source, and expected package name, and that lockfiles declare exactly one current release version.
 3b. Keep package security validation in Forgejo/Gitea CI so unsafe names, exact manifest-version/name/version/checksum mismatches, missing manifests, duplicate project manifest versions and packages, duplicate lock packages, duplicate package manifest names, versions, and checksums, and lockfile errors remain release blockers.
-4. Add small examples for each foundation feature before adding bigger syntax. The object-field foundation now includes positive and negative validation for field expressions such as `SET player.score player.name`, `SET player.score player.score + 1`, `SET player.name player.score + 1`, and arithmetic/text expression mismatches; typed containers also accept a map with nested type metadata when it is added to a `LIST OF MAP`; broader alias/control-flow checking remains planned.
+4. Add small examples for each foundation feature before adding bigger syntax. The object-field foundation now includes positive and negative validation for field expressions such as `SET player.score player.name`, `SET player.score player.score + 1`, `SET player.name player.score + 1`, aliases such as `SET alias player` followed by `SET alias.score ...`, and arithmetic/text expression mismatches; typed containers also accept a map with nested type metadata when it is added to a `LIST OF MAP`; broader alias/control-flow checking remains planned.
 
 ## Complete-platform milestones
 

src/claro.c

@@ -618,7 +618,7 @@ static TypeFieldCheck *collect_class_field_type_checks(FILE *f){
  return checks;
 }
 static TypeMethodCheck *collect_class_method_type_checks(FILE *f){ TypeMethodCheck *checks=NULL; char line[4096]; char current_class[128]=""; while(fgets(line,sizeof(line),f)){ char tmp[4096],up[64],w[128]; char *t; strncpy(tmp,line,sizeof(tmp)-1); tmp[sizeof(tmp)-1]=0; t=trim_inplace(tmp); if(is_blank_or_comment(t)) continue; first_word(t,w,sizeof(w)); upper_copy(up,w,sizeof(up)); if(!strcmp(up,"CLASS")){ const char *pcur=t+5; char *cls=unquote_token(&pcur); snprintf(current_class,sizeof(current_class),"%s",trim_inplace(cls)); free(cls); continue; } if((!strcmp(up,"END")||!strcmp(up,"ENDCLASS"))&&current_class[0]){ current_class[0]=0; continue; } if(current_class[0]&&!strcmp(up,"TEACH")){ char teachline[4096]; char *fname=NULL; char **params=NULL; int pcnt=0; strncpy(teachline,t,sizeof(teachline)-1); teachline[sizeof(teachline)-1]=0; parse_teach_parts(teachline,&fname,&params,&pcnt); add_type_method_check(&checks,current_class,trim_inplace(fname)); while(fgets(line,sizeof(line),f)){ char inner[4096],iup[64],iw[128]; char *it; strncpy(inner,line,sizeof(inner)-1); inner[sizeof(inner)-1]=0; it=trim_inplace(inner); if(is_blank_or_comment(it)) continue; first_word(it,iw,sizeof(iw)); upper_copy(iup,iw,sizeof(iup)); if(!strcmp(iup,"END")||!strcmp(iup,"LEARNED")) break; } } } rewind(f); return checks; }
-static int typecheck_file(const char *path){ FILE *f=fopen(path,"rb"); char line[4096]; int line_no=0,errs=0; Var *types=NULL; TypeParamCheck *param_checks=NULL; TypeFieldCheck *field_checks=NULL; TypeMethodCheck *method_checks=NULL; TypeArityCheck *arity_checks=NULL; if(!f){ fprintf(stderr,"Could not open %s\n",path); return 1; } param_checks=collect_function_param_type_checks(f); arity_checks=collect_function_arity_checks(f); field_checks=collect_class_field_type_checks(f); method_checks=collect_class_method_type_checks(f); type_env_set(&types,"RESULT","ANY"); type_env_set(&types,"LASTERROR","TEXT"); type_env_set(&types,"LASTERRORFILE","TEXT"); type_env_set(&types,"LASTERRORLINE","NUMBER"); type_env_set(&types,"LASTEXIT","NUMBER"); while(fgets(line,sizeof(line),f)){ char tmp[4096],up[64],w[128]; char *t; line_no++; strncpy(tmp,line,sizeof(line)-1); tmp[sizeof(tmp)-1]=0; t=trim_inplace(tmp); if(is_blank_or_comment(t)) continue; first_word(t,w,sizeof(w)); upper_copy(up,w,sizeof(up)); if(!strcmp(up,"SET")){ char *name=NULL,*type=NULL,*expr=NULL; const char *got,*old; parse_set_for_typecheck2(t,&name,&type,&expr); if(name&&*trim_inplace(name)){ char *nt=trim_inplace(name); char *tt=type?trim_inplace(type):NULL; got=simple_expr_type(types,expr); old=type_env_get(types,nt); if(tt&&*tt){ if(got&&!type_words_match(tt,got)){ printf("%s:%d: Type mismatch for %s: expected %s, but this value looks like %s.\n",path,line_no,nt,tt,got); errs++; } type_env_set(&types,nt,tt); } else if(old){ if(got&&!type_words_match(old,got)){ if(strchr(nt,'.')) printf("%s:%d: Type mismatch for field %s: expected %s, but this value looks like %s.\n",path,line_no,nt,old,got); else printf("%s:%d: Type mismatch for %s: it was first set as %s, but this value looks like %s.\n",path,line_no,nt,old,got); errs++; } } else if(strchr(nt,'.')){ char objname[128],fieldname[128]; char *dot=strchr(nt,'.'); const char *objtype; snprintf(objname,sizeof(objname),"%.*s",(int)(dot-nt),nt); snprintf(fieldname,sizeof(fieldname),"%s",dot+1); objtype=type_env_get(types,objname); if(objtype&&starts_ci(objtype,"OBJECT:")){ const char *cls=objtype+7; if(!type_field_check_for(field_checks,cls,fieldname)){ if(got&&!strchr(expr,'+')&&!strchr(expr,'-')&&!strchr(expr,'*')&&!strchr(expr,'/')) printf("%s:%d: Object %s has no field %s. Check the field name or add HAS %s %s to the class.\n",path,line_no,cls,fieldname,fieldname,got); else printf("%s:%d: Object %s has no field %s. Check the field name or add the field to the class with the right type.\n",path,line_no,cls,fieldname); errs++; } } else { printf("%s:%d: Object %s is not known yet. Create it with NEW ClassName %s before setting %s.\n",path,line_no,objname,objname,nt); errs++; } } else if(got) type_env_set(&types,nt,got); else type_env_set(&types,nt,"ANY"); } free(name); free(type); free(expr); }
+static int typecheck_file(const char *path){ FILE *f=fopen(path,"rb"); char line[4096]; int line_no=0,errs=0; Var *types=NULL; TypeParamCheck *param_checks=NULL; TypeFieldCheck *field_checks=NULL; TypeMethodCheck *method_checks=NULL; TypeArityCheck *arity_checks=NULL; if(!f){ fprintf(stderr,"Could not open %s\n",path); return 1; } param_checks=collect_function_param_type_checks(f); arity_checks=collect_function_arity_checks(f); field_checks=collect_class_field_type_checks(f); method_checks=collect_class_method_type_checks(f); type_env_set(&types,"RESULT","ANY"); type_env_set(&types,"LASTERROR","TEXT"); type_env_set(&types,"LASTERRORFILE","TEXT"); type_env_set(&types,"LASTERRORLINE","NUMBER"); type_env_set(&types,"LASTEXIT","NUMBER"); while(fgets(line,sizeof(line),f)){ char tmp[4096],up[64],w[128]; char *t; line_no++; strncpy(tmp,line,sizeof(line)-1); tmp[sizeof(tmp)-1]=0; t=trim_inplace(tmp); if(is_blank_or_comment(t)) continue; first_word(t,w,sizeof(w)); upper_copy(up,w,sizeof(up)); if(!strcmp(up,"SET")){ char *name=NULL,*type=NULL,*expr=NULL; const char *got,*old; parse_set_for_typecheck2(t,&name,&type,&expr); if(name&&*trim_inplace(name)){ char *nt=trim_inplace(name); char *tt=type?trim_inplace(type):NULL; got=simple_expr_type(types,expr); old=type_env_get(types,nt); if(tt&&*tt){ if(got&&!type_words_match(tt,got)){ printf("%s:%d: Type mismatch for %s: expected %s, but this value looks like %s.\n",path,line_no,nt,tt,got); errs++; } type_env_set(&types,nt,tt); } else if(old){ if(got&&!type_words_match(old,got)){ if(strchr(nt,'.')) printf("%s:%d: Type mismatch for field %s: expected %s, but this value looks like %s.\n",path,line_no,nt,old,got); else printf("%s:%d: Type mismatch for %s: it was first set as %s, but this value looks like %s.\n",path,line_no,nt,old,got); errs++; } } else if(strchr(nt,'.')){ char objname[128],fieldname[128]; char *dot=strchr(nt,'.'); const char *objtype; snprintf(objname,sizeof(objname),"%.*s",(int)(dot-nt),nt); snprintf(fieldname,sizeof(fieldname),"%s",dot+1); objtype=type_env_get(types,objname); if(objtype&&starts_ci(objtype,"OBJECT:")){ const char *cls=objtype+7; if(!type_field_check_for(field_checks,cls,fieldname)){ if(got&&!strchr(expr,'+')&&!strchr(expr,'-')&&!strchr(expr,'*')&&!strchr(expr,'/')) printf("%s:%d: Object %s has no field %s. Check the field name or add HAS %s %s to the class.\n",path,line_no,cls,fieldname,fieldname,got); else printf("%s:%d: Object %s has no field %s. Check the field name or add the field to the class with the right type.\n",path,line_no,cls,fieldname); errs++; } else { const char *fieldtype=type_field_check_for(field_checks,cls,fieldname); if(got&&!type_words_match(fieldtype,got)){ printf("%s:%d: Type mismatch for field %s.%s: expected %s, but this value looks like %s.\n",path,line_no,objname,fieldname,fieldtype,got); errs++; } } } else { printf("%s:%d: Object %s is not known yet. Create it with NEW ClassName %s before setting %s.\n",path,line_no,objname,objname,nt); errs++; } } else if(got) type_env_set(&types,nt,got); else type_env_set(&types,nt,"ANY"); } free(name); free(type); free(expr); }
   else if(!strcmp(up,"ADD")){ const char *to=find_word_ci(t,"TO"); if(to){ char *expr=substr(t+3,to); char *name=xstrdup(trim_inplace((char*)to+2)); const char *listtype=type_env_get(types,name); const char *need=container_member_type(listtype,"LIST"); const char *got=simple_expr_type(types,expr); if(need&&got&&!type_words_match(need,got)){ printf("%s:%d: Type mismatch for list %s: expected %s item, but this value looks like %s.\n",path,line_no,name,need,got); errs++; } free(expr); free(name); } }
   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); }

tests/typecheck_object_field_alias_bad.claro

@@ -0,0 +1,7 @@
+CLASS Player
+    HAS score NUMBER
+END
+
+NEW Player player
+SET alias player
+SET alias.score "ten"

tests/typecheck_object_field_alias_good.claro

@@ -0,0 +1,7 @@
+CLASS Player
+    HAS score NUMBER
+END
+
+NEW Player player
+SET alias player
+SET alias.score 10

tools/validate_typecheck_diagnostics.py

@@ -134,6 +134,9 @@ EXPECTED = {
     "tests/typecheck_object_field_unknown_object_bad.claro": [
         "tests/typecheck_object_field_unknown_object_bad.claro:5: Object player is not known yet. Create it with NEW ClassName player before setting player.score.",
     ],
+    "tests/typecheck_object_field_alias_bad.claro": [
+        "tests/typecheck_object_field_alias_bad.claro:7: Type mismatch for field alias.score: expected NUMBER, but this value looks like TEXT.",
+    ],
 }
 
 EXPECTED_OK = [
@@ -149,6 +152,7 @@ EXPECTED_OK = [
     "tests/typecheck_object_field_check_type_number_good.claro",
     "tests/typecheck_object_field_check_type_text_good.claro",
     "tests/typecheck_object_field_check_type_text_yesno_good.claro",
+    "tests/typecheck_object_field_alias_good.claro",
     "tests/typecheck_nested_container_good.claro",
     "tests/37_object_field_types.claro",
 ]