typecheck: accept complete conditional returns

docs/CURRENT_STATUS.md

@@ -53,7 +53,7 @@ Ready now:
 - `TYPE OF` and `CHECK TYPE`
 - `CHECK TYPE` rejects unknown expected type names with a beginner-facing list of supported types
 - 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 `RETURN` expressions, empty `RETURN` statements, declarations that contain no `RETURN`, and declarations whose only return is inside a conditional, with focused validation for both modern and compatibility function syntax; `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including method return expressions
+- simple function and object-method return checks with `TEACH name ... RETURNS TYPE`, including learner-facing diagnostics for unknown declared return types, mismatched `RETURN` expressions, empty `RETURN` statements, declarations that contain no `RETURN`, and declarations whose only return is inside an incomplete conditional; complete `IF`/`ELSE` return branches are accepted, with focused validation for modern and compatibility function syntax; `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including method return expressions
 - 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, 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 a plain beginner-facing unknown-field diagnostic when the assigned expression type is not inferable yet
 

docs/ROADMAP.md

@@ -37,7 +37,7 @@ See `CURRENT_STATUS.md` for the detailed feature matrix.
 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`, explicitly typed field assignments, explicit typed assignments to undeclared fields, simple and chained aliases such as `SET alias player`, `SET backup alias`, followed by `SET backup.score ...` or `CHECK TYPE backup.score IS ...`, chained aliases in object-method calls through both modern `DO` and compatibility `CALL ... WITH` forms (including a dedicated positive modern `DO` fixture), 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.
 5. Keep the focused typecheck validator complete: every `typecheck_*.claro` fixture, including positive fixtures, must be exercised by release validation.
 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 declared return types honest: `claro typecheck` now reports friendly diagnostics for unknown declared return types, mismatched and empty return expressions, declarations with no `RETURN`, and declarations whose only return is inside a conditional, when a simple function or object method declares `RETURNS TYPE`; modern and compatibility function syntax are both covered. `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including object methods. Focused fixtures cover these cases. Full path-sensitive analysis proving that every `IF`/`ELSE` branch returns remains planned.
+- Keep declared return types honest: `claro typecheck` now reports friendly diagnostics for unknown declared return types, mismatched and empty return expressions, declarations with no `RETURN`, and incomplete conditional branches, when a simple function or object method declares `RETURNS TYPE`; complete `IF`/`ELSE` return branches are accepted, and modern and compatibility function syntax are both covered. `CHECK TYPE` parameter metadata also informs arithmetic return-expression checking, including object methods. Focused fixtures cover these cases. Full path-sensitive analysis across nested conditionals and loops remains planned.
 
 ## Complete-platform milestones
 

src/claro.c

@@ -623,11 +623,12 @@ 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; TypeReturnCheck *return_checks=NULL; char current_func[256]=""; char current_class[128]=""; int in_teach=0,return_seen=0,top_level_return_seen=0,nested_blocks=0; 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); return_checks=collect_function_return_type_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,"CLASS")){ const char *pcur=t+5; char *cls=unquote_token(&pcur); snprintf(current_class,sizeof(current_class),"%s",trim_inplace(cls)); free(cls); }
-else if(!strcmp(up,"TEACH")){ char teachline[4096],full_name[256],*fname=NULL,**params=NULL; int pcnt=0; strncpy(teachline,t,sizeof(teachline)-1); teachline[sizeof(teachline)-1]=0; parse_teach_parts(teachline,&fname,&params,&pcnt); if(current_class[0]) snprintf(full_name,sizeof(full_name),"%s.%s",current_class,fname); else snprintf(full_name,sizeof(full_name),"%s",fname); current_func[0]=0; return_seen=0; top_level_return_seen=0; nested_blocks=0; in_teach=1; { const char *declared_return=type_return_check_for(return_checks,full_name); if(declared_return&&!claro_is_type_word(declared_return)){ printf("%s:%d: %s %s declares an unknown return type %s. Use a Claro type such as NUMBER, TEXT, YESNO, LIST, or MAP.\n",path,line_no,strchr(full_name,'.')?"Method":"Function",full_name,declared_return); errs++; } else if(declared_return) snprintf(current_func,sizeof(current_func),"%s",full_name); } }
-else if(!strcmp(up,"IF")){ if(in_teach) nested_blocks++; }
- else if(!strcmp(up,"END")||!strcmp(up,"LEARNED")||!strcmp(up,"ENDIF")){ if(in_teach&&nested_blocks>0){ nested_blocks--; } else if(in_teach){ if(current_func[0]&&!return_seen){ const char *need=type_return_check_for(return_checks,current_func); printf("%s:%d: %s %s declares RETURNS %s but has no RETURN statement. Add RETURN with a %s value.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } else if(current_func[0]&&!top_level_return_seen){ const char *need=type_return_check_for(return_checks,current_func); printf("%s:%d: %s %s declares RETURNS %s but does not return a %s value on every path. Add RETURN to each branch or after the conditional.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } in_teach=0; current_func[0]=0; } else current_class[0]=0; }
-  else if(!strcmp(up,"RETURN")&&current_func[0]){ const char *need=type_return_check_for(return_checks,current_func); char *return_expr=trim_inplace(t+6); const char *got=simple_expr_type(types,return_expr); return_seen=1; if(nested_blocks==0) top_level_return_seen=1; if(need&&!*return_expr){ printf("%s:%d: %s %s needs a %s value after RETURN. Add a %s expression.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } else if(need&&got&&!type_words_match(need,got)){ printf("%s:%d: Type mismatch for return from %s: expected %s, but this value looks like %s.\n",path,line_no,current_func,need,got); errs++; } }
+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; TypeReturnCheck *return_checks=NULL; char current_func[256]=""; char current_class[128]=""; int in_teach=0,return_seen=0,top_level_return_seen=0,nested_blocks=0,conditional_paths_complete=1; int branch_returned[64],branch_has_else[64]; 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); return_checks=collect_function_return_type_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(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); }
+else if(!strcmp(up,"TEACH")){ char teachline[4096],full_name[256],*fname=NULL,**params=NULL; int pcnt=0; strncpy(teachline,t,sizeof(teachline)-1); teachline[sizeof(teachline)-1]=0; parse_teach_parts(teachline,&fname,&params,&pcnt); if(current_class[0]) snprintf(full_name,sizeof(full_name),"%s.%s",current_class,fname); else snprintf(full_name,sizeof(full_name),"%s",fname); current_func[0]=0; return_seen=0; top_level_return_seen=0; nested_blocks=0; conditional_paths_complete=1; in_teach=1; { const char *declared_return=type_return_check_for(return_checks,full_name); if(declared_return&&!claro_is_type_word(declared_return)){ printf("%s:%d: %s %s declares an unknown return type %s. Use a Claro type such as NUMBER, TEXT, YESNO, LIST, or MAP.\n",path,line_no,strchr(full_name,'.')?"Method":"Function",full_name,declared_return); errs++; } else if(declared_return) snprintf(current_func,sizeof(current_func),"%s",full_name); } }
+else if(!strcmp(up,"IF")){ if(in_teach){ if(nested_blocks<64){ branch_returned[nested_blocks]=0; branch_has_else[nested_blocks]=0; } nested_blocks++; } }
+ else if(!strcmp(up,"ELSE")){ if(in_teach&&nested_blocks>0&&nested_blocks<=64){ if(!branch_returned[nested_blocks-1]) conditional_paths_complete=0; branch_has_else[nested_blocks-1]=1; branch_returned[nested_blocks-1]=0; } }
+ else if(!strcmp(up,"END")||!strcmp(up,"LEARNED")||!strcmp(up,"ENDIF")){ if(in_teach&&nested_blocks>0){ if(nested_blocks<=64&&(!branch_has_else[nested_blocks-1]||!branch_returned[nested_blocks-1])) conditional_paths_complete=0; nested_blocks--; } else if(in_teach){ if(current_func[0]&&!return_seen){ const char *need=type_return_check_for(return_checks,current_func); printf("%s:%d: %s %s declares RETURNS %s but has no RETURN statement. Add RETURN with a %s value.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } else if(current_func[0]&&(!top_level_return_seen&&!conditional_paths_complete)){ const char *need=type_return_check_for(return_checks,current_func); printf("%s:%d: %s %s declares RETURNS %s but does not return a %s value on every path. Add RETURN to each branch or after the conditional.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } in_teach=0; current_func[0]=0; } else current_class[0]=0; }
+  else if(!strcmp(up,"RETURN")&&current_func[0]){ const char *need=type_return_check_for(return_checks,current_func); char *return_expr=trim_inplace(t+6); const char *got=simple_expr_type(types,return_expr); return_seen=1; if(nested_blocks==0) top_level_return_seen=1; else if(nested_blocks<=64) branch_returned[nested_blocks-1]=1; if(need&&!*return_expr){ printf("%s:%d: %s %s needs a %s value after RETURN. Add a %s expression.\n",path,line_no,strchr(current_func,'.')?"Method":"Function",current_func,need,need); errs++; } else if(need&&got&&!type_words_match(need,got)){ printf("%s:%d: Type mismatch for return from %s: expected %s, but this value looks like %s.\n",path,line_no,current_func,need,got); errs++; } }
  else 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(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 *declared=type_field_check_for(field_checks,objtype+7,fieldname); if(declared&&got&&!type_words_match(declared,got)){ char text_operator=(ci_eq(declared,"NUMBER")&&ci_eq(got,"TEXT"))?(text_operand_for_operator(types,expr,'+')?'+':(text_operand_for_operator(types,expr,'-')?'-':(text_operand_for_operator(types,expr,'*')?'*':(text_operand_for_operator(types,expr,'/')?'/':0)))):0; const char *text_operand=text_operator?text_operand_for_operator(types,expr,text_operator):NULL; if(text_operand){ printf("%s:%d: Type mismatch for field %s: %s needs NUMBER values, but %s looks like TEXT.\n",path,line_no,nt,text_operator=='+'?"addition":(text_operator=='-'?"subtraction":(text_operator=='*'?"multiplication":"division")),text_operand); } else { printf("%s:%d: Type mismatch for field %s: expected %s, but this value looks like %s.\n",path,line_no,nt,declared,got); } errs++; } else if(!declared){ 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,objtype+7,fieldname,fieldname,tt); errs++; } else 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++; } } else 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++; } } else 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,'.')){ char text_operator=(ci_eq(old,"NUMBER")&&ci_eq(got,"TEXT"))?(text_operand_for_operator(types,expr,'+')?'+':(text_operand_for_operator(types,expr,'-')?'-':(text_operand_for_operator(types,expr,'*')?'*':(text_operand_for_operator(types,expr,'/')?'/':0)))):0; const char *text_operand=text_operator?text_operand_for_operator(types,expr,text_operator):NULL; if(text_operand) printf("%s:%d: Type mismatch for field %s: %s needs NUMBER values, but %s looks like TEXT.\n",path,line_no,nt,text_operator=='+'?"addition":(text_operator=='-'?"subtraction":(text_operator=='*'?"multiplication":"division")),text_operand); else 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); } }

tests/typecheck_function_branch_complete_good.claro

@@ -0,0 +1,9 @@
+TEACH choose flag RETURNS NUMBER
+    IF flag
+        RETURN 1
+    ELSE
+        RETURN 2
+    END
+END
+
+DO choose YES

tools/validate_typecheck_diagnostics.py

@@ -216,6 +216,7 @@ EXPECTED_OK = [
     "tests/typecheck_function_return_good.claro",
     "tests/typecheck_function_compat_return_good.claro",
     "tests/typecheck_function_return_expression_good.claro",
+    "tests/typecheck_function_branch_complete_good.claro",
     "tests/typecheck_method_return_good.claro",
     "tests/typecheck_method_return_expression_good.claro",
     "tests/typecheck_function_multi_good.claro",