1mod expr_checker;
2mod item_checker;
3mod stmt_checker;
4mod type_env;
5use crate::modules::{LoadedModule, ModuleImports};
6use crate::{
7 ast::*,
8 config::LustConfig,
9 error::{LustError, Result},
10};
11pub(super) use alloc::{
12 boxed::Box,
13 format,
14 string::{String, ToString},
15 vec,
16 vec::Vec,
17};
18use core::mem;
19use hashbrown::{HashMap, HashSet};
20pub use type_env::FunctionSignature;
21pub use type_env::TypeEnv;
22pub struct TypeChecker {
23 env: TypeEnv,
24 current_function_return_type: Option<Type>,
25 in_loop: bool,
26 pending_generic_instances: Option<HashMap<String, Type>>,
27 expected_lambda_signature: Option<(Vec<Type>, Option<Type>)>,
28 current_trait_bounds: HashMap<String, Vec<String>>,
29 current_module: Option<String>,
30 imports_by_module: HashMap<String, ModuleImports>,
31 expr_types_by_module: HashMap<String, HashMap<Span, Type>>,
32 variable_types_by_module: HashMap<String, HashMap<Span, Type>>,
33 short_circuit_info: HashMap<String, HashMap<Span, ShortCircuitInfo>>,
34}
35
36pub struct TypeCollection {
37 pub expr_types: HashMap<String, HashMap<Span, Type>>,
38 pub variable_types: HashMap<String, HashMap<Span, Type>>,
39}
40
41#[derive(Clone, Debug)]
42struct ShortCircuitInfo {
43 truthy: Option<Type>,
44 falsy: Option<Type>,
45 option_inner: Option<Type>,
46}
47
48impl TypeChecker {
49 pub fn new() -> Self {
50 Self::with_config(&LustConfig::default())
51 }
52
53 pub fn with_config(config: &LustConfig) -> Self {
54 Self {
55 env: TypeEnv::with_config(config),
56 current_function_return_type: None,
57 in_loop: false,
58 pending_generic_instances: None,
59 expected_lambda_signature: None,
60 current_trait_bounds: HashMap::new(),
61 current_module: None,
62 imports_by_module: HashMap::new(),
63 expr_types_by_module: HashMap::new(),
64 variable_types_by_module: HashMap::new(),
65 short_circuit_info: HashMap::new(),
66 }
67 }
68
69 fn dummy_span() -> Span {
70 Span::new(0, 0, 0, 0)
71 }
72
73 pub fn check_module(&mut self, items: &[Item]) -> Result<()> {
74 for item in items {
75 self.register_type_definition(item)?;
76 }
77
78 self.validate_struct_cycles()?;
79 self.env.push_scope();
80 self.register_module_init_locals(items)?;
81 for item in items {
82 self.check_item(item)?;
83 }
84
85 self.env.pop_scope();
86 Ok(())
87 }
88
89 pub fn check_program(&mut self, modules: &[LoadedModule]) -> Result<()> {
90 for m in modules {
91 self.current_module = Some(m.path.clone());
92 for item in &m.items {
93 self.register_type_definition(item)?;
94 }
95 }
96
97 self.validate_struct_cycles()?;
98 for m in modules {
99 self.current_module = Some(m.path.clone());
100 self.env.push_scope();
101 self.register_module_init_locals(&m.items)?;
102 for item in &m.items {
103 self.check_item(item)?;
104 }
105
106 self.env.pop_scope();
107 }
108
109 self.current_module = None;
110 Ok(())
111 }
112
113 fn validate_struct_cycles(&self) -> Result<()> {
114 use hashbrown::{HashMap, HashSet};
115 let struct_defs = self.env.struct_definitions();
116 if struct_defs.is_empty() {
117 return Ok(());
118 }
119
120 let mut simple_to_full: HashMap<String, Vec<String>> = HashMap::new();
121 for name in struct_defs.keys() {
122 let simple = name.rsplit('.').next().unwrap_or(name).to_string();
123 simple_to_full.entry(simple).or_default().push(name.clone());
124 }
125
126 let mut struct_has_weak: HashMap<String, bool> = HashMap::new();
127 for (name, def) in &struct_defs {
128 let has_weak = def
129 .fields
130 .iter()
131 .any(|field| matches!(field.ownership, FieldOwnership::Weak));
132 struct_has_weak.insert(name.clone(), has_weak);
133 }
134
135 let mut graph: HashMap<String, Vec<String>> = HashMap::new();
136 for (name, def) in &struct_defs {
137 let module_prefix = name.rsplit_once('.').map(|(module, _)| module.to_string());
138 let mut edges: HashSet<String> = HashSet::new();
139 for field in &def.fields {
140 if matches!(field.ownership, FieldOwnership::Weak) {
141 let target = field.weak_target.as_ref().ok_or_else(|| {
142 self.type_error(format!(
143 "Field '{}.{}' is marked as 'ref' but has no target type",
144 name, field.name
145 ))
146 })?;
147 let target_name = if let TypeKind::Named(inner) = &target.kind {
148 inner
149 } else {
150 return Err(self.type_error(format!(
151 "Field '{}.{}' uses 'ref' but only struct types are supported",
152 name, field.name
153 )));
154 };
155 let resolved = self.resolve_struct_name_for_cycle(
156 target_name.as_str(),
157 module_prefix.as_deref(),
158 &struct_defs,
159 &simple_to_full,
160 );
161 if resolved.is_none() {
162 return Err(self.type_error(format!(
163 "Field '{}.{}' uses 'ref' but '{}' is not a known struct type",
164 name, field.name, target_name
165 )));
166 }
167
168 continue;
169 }
170
171 self.collect_strong_struct_targets(
172 &field.ty,
173 module_prefix.as_deref(),
174 &struct_defs,
175 &simple_to_full,
176 &mut edges,
177 );
178 }
179
180 graph.insert(name.clone(), edges.into_iter().collect());
181 }
182
183 fn dfs(
184 node: &str,
185 graph: &HashMap<String, Vec<String>>,
186 visited: &mut HashSet<String>,
187 on_stack: &mut HashSet<String>,
188 stack: &mut Vec<String>,
189 ) -> Option<Vec<String>> {
190 visited.insert(node.to_string());
191 on_stack.insert(node.to_string());
192 stack.push(node.to_string());
193 if let Some(neighbors) = graph.get(node) {
194 for neighbor in neighbors {
195 if !visited.contains(neighbor) {
196 if let Some(cycle) = dfs(neighbor, graph, visited, on_stack, stack) {
197 return Some(cycle);
198 }
199 } else if on_stack.contains(neighbor) {
200 if let Some(pos) = stack.iter().position(|n| n == neighbor) {
201 let mut cycle = stack[pos..].to_vec();
202 cycle.push(neighbor.clone());
203 return Some(cycle);
204 }
205 }
206 }
207 }
208
209 stack.pop();
210 on_stack.remove(node);
211 None
212 }
213
214 let mut visited: HashSet<String> = HashSet::new();
215 let mut on_stack: HashSet<String> = HashSet::new();
216 let mut stack: Vec<String> = Vec::new();
217 for name in struct_defs.keys() {
218 if !visited.contains(name) {
219 if let Some(cycle) = dfs(name, &graph, &mut visited, &mut on_stack, &mut stack) {
220 let contains_weak = cycle
221 .iter()
222 .any(|node| struct_has_weak.get(node).copied().unwrap_or(false));
223 if contains_weak {
224 continue;
225 }
226
227 break;
229 }
234 }
235 }
236
237 Ok(())
238 }
239
240 fn collect_strong_struct_targets(
241 &self,
242 ty: &Type,
243 parent_module: Option<&str>,
244 struct_defs: &HashMap<String, StructDef>,
245 simple_to_full: &HashMap<String, Vec<String>>,
246 out: &mut HashSet<String>,
247 ) {
248 match &ty.kind {
249 TypeKind::Named(name) => {
250 if let Some(resolved) = self.resolve_struct_name_for_cycle(
251 name,
252 parent_module,
253 struct_defs,
254 simple_to_full,
255 ) {
256 out.insert(resolved);
257 }
258 }
259
260 TypeKind::Array(inner)
261 | TypeKind::Ref(inner)
262 | TypeKind::MutRef(inner)
263 | TypeKind::Option(inner) => {
264 self.collect_strong_struct_targets(
265 inner,
266 parent_module,
267 struct_defs,
268 simple_to_full,
269 out,
270 );
271 }
272
273 TypeKind::Map(key, value) => {
274 self.collect_strong_struct_targets(
275 key,
276 parent_module,
277 struct_defs,
278 simple_to_full,
279 out,
280 );
281 self.collect_strong_struct_targets(
282 value,
283 parent_module,
284 struct_defs,
285 simple_to_full,
286 out,
287 );
288 }
289
290 TypeKind::Tuple(elements) | TypeKind::Union(elements) => {
291 for element in elements {
292 self.collect_strong_struct_targets(
293 element,
294 parent_module,
295 struct_defs,
296 simple_to_full,
297 out,
298 );
299 }
300 }
301
302 TypeKind::Result(ok, err) => {
303 self.collect_strong_struct_targets(
304 ok,
305 parent_module,
306 struct_defs,
307 simple_to_full,
308 out,
309 );
310 self.collect_strong_struct_targets(
311 err,
312 parent_module,
313 struct_defs,
314 simple_to_full,
315 out,
316 );
317 }
318
319 TypeKind::GenericInstance { type_args, .. } => {
320 for arg in type_args {
321 self.collect_strong_struct_targets(
322 arg,
323 parent_module,
324 struct_defs,
325 simple_to_full,
326 out,
327 );
328 }
329 }
330
331 _ => {}
332 }
333 }
334
335 fn resolve_struct_name_for_cycle(
336 &self,
337 name: &str,
338 parent_module: Option<&str>,
339 struct_defs: &HashMap<String, StructDef>,
340 simple_to_full: &HashMap<String, Vec<String>>,
341 ) -> Option<String> {
342 if struct_defs.contains_key(name) {
343 return Some(name.to_string());
344 }
345
346 if name.contains('.') {
347 return None;
348 }
349
350 if let Some(candidates) = simple_to_full.get(name) {
351 if candidates.len() == 1 {
352 return Some(candidates[0].clone());
353 }
354
355 if let Some(module) = parent_module {
356 for candidate in candidates {
357 if let Some((candidate_module, _)) = candidate.rsplit_once('.') {
358 if candidate_module == module {
359 return Some(candidate.clone());
360 }
361 }
362 }
363 }
364 }
365
366 None
367 }
368
369 pub fn set_imports_by_module(&mut self, map: HashMap<String, ModuleImports>) {
370 self.imports_by_module = map;
371 }
372
373 pub fn take_type_info(&mut self) -> TypeCollection {
374 TypeCollection {
375 expr_types: mem::take(&mut self.expr_types_by_module),
376 variable_types: mem::take(&mut self.variable_types_by_module),
377 }
378 }
379
380 pub fn take_option_coercions(&mut self) -> HashMap<String, HashSet<Span>> {
381 let mut result: HashMap<String, HashSet<Span>> = HashMap::new();
382 let info = mem::take(&mut self.short_circuit_info);
383 for (module, entries) in info {
384 let mut spans: HashSet<Span> = HashSet::new();
385 for (span, entry) in entries {
386 if entry.option_inner.is_some() {
387 spans.insert(span);
388 }
389 }
390 if !spans.is_empty() {
391 result.insert(module, spans);
392 }
393 }
394
395 result
396 }
397
398 pub fn function_signatures(&self) -> HashMap<String, type_env::FunctionSignature> {
399 self.env.function_signatures()
400 }
401
402 pub fn struct_definitions(&self) -> HashMap<String, StructDef> {
403 self.env.struct_definitions()
404 }
405
406 pub fn enum_definitions(&self) -> HashMap<String, EnumDef> {
407 self.env.enum_definitions()
408 }
409
410 fn register_module_init_locals(&mut self, items: &[Item]) -> Result<()> {
411 let module = match &self.current_module {
412 Some(m) => m.clone(),
413 None => return Ok(()),
414 };
415 let init_name = format!("__init@{}", module);
416 for item in items {
417 if let ItemKind::Function(func) = &item.kind {
418 if func.name == init_name {
419 for stmt in &func.body {
420 if let StmtKind::Local {
421 bindings,
422 ref mutable,
423 initializer,
424 } = &stmt.kind
425 {
426 self.check_local_stmt(
427 bindings.as_slice(),
428 *mutable,
429 initializer.as_ref().map(|values| values.as_slice()),
430 )?;
431 }
432 }
433 }
434 }
435 }
436
437 Ok(())
438 }
439
440 pub fn resolve_function_key(&self, name: &str) -> String {
441 if name.contains('.') || name.contains(':') {
442 return name.to_string();
443 }
444
445 if let Some(module) = &self.current_module {
446 if let Some(imports) = self.imports_by_module.get(module) {
447 if let Some(fq) = imports.function_aliases.get(name) {
448 return fq.clone();
449 }
450 }
451
452 let qualified = format!("{}.{}", module, name);
453 if self.env.lookup_function(&qualified).is_some() {
454 return qualified;
455 }
456
457 if self.env.lookup_function(name).is_some() {
458 return name.to_string();
459 }
460
461 return qualified;
462 }
463
464 name.to_string()
465 }
466
467 pub fn resolve_value_key(&self, name: &str) -> String {
468 if name.contains('.') || name.contains(':') {
469 return name.to_string();
470 }
471
472 if let Some(module) = &self.current_module {
473 if let Some(imports) = self.imports_by_module.get(module) {
474 if let Some(fq) = imports.function_aliases.get(name) {
475 return fq.clone();
476 }
477 }
478
479 return format!("{}.{}", module, name);
480 }
481
482 name.to_string()
483 }
484
485 pub fn resolve_module_alias(&self, alias: &str) -> Option<String> {
486 if let Some(module) = &self.current_module {
487 if let Some(imports) = self.imports_by_module.get(module) {
488 if let Some(m) = imports.module_aliases.get(alias) {
489 return Some(m.clone());
490 }
491 }
492 }
493
494 None
495 }
496
497 pub fn register_external_struct(&mut self, mut def: StructDef) -> Result<()> {
498 def.name = self.resolve_type_key(&def.name);
499 for field in &mut def.fields {
500 field.ty = self.canonicalize_type(&field.ty);
501 if let Some(target) = &field.weak_target {
502 field.weak_target = Some(self.canonicalize_type(target));
503 }
504 }
505 self.env.register_struct(&def)
506 }
507
508 pub fn register_external_enum(&mut self, mut def: EnumDef) -> Result<()> {
509 def.name = self.resolve_type_key(&def.name);
510 for variant in &mut def.variants {
511 if let Some(fields) = &mut variant.fields {
512 for field in fields {
513 *field = self.canonicalize_type(field);
514 }
515 }
516 }
517 self.env.register_enum(&def)
518 }
519
520 pub fn register_external_trait(&mut self, mut def: TraitDef) -> Result<()> {
521 def.name = self.resolve_type_key(&def.name);
522 for method in &mut def.methods {
523 for param in &mut method.params {
524 param.ty = self.canonicalize_type(¶m.ty);
525 }
526 if let Some(ret) = method.return_type.clone() {
527 method.return_type = Some(self.canonicalize_type(&ret));
528 }
529 }
530 self.env.register_trait(&def)
531 }
532
533 pub fn register_external_function(
534 &mut self,
535 (name, mut signature): (String, FunctionSignature),
536 ) -> Result<()> {
537 signature.params = signature
538 .params
539 .into_iter()
540 .map(|ty| self.canonicalize_type(&ty))
541 .collect();
542 signature.return_type = self.canonicalize_type(&signature.return_type);
543 let canonical = self.resolve_type_key(&name);
544 self.env.register_or_update_function(canonical, signature)
545 }
546
547 pub fn register_external_constant(&mut self, name: String, ty: Type) -> Result<()> {
548 let canonical_ty = self.canonicalize_type(&ty);
549 let canonical_name = self.resolve_value_key(&name);
550 self.env.register_constant(canonical_name, canonical_ty)
551 }
552
553 pub fn register_external_impl(&mut self, mut impl_block: ImplBlock) -> Result<()> {
554 impl_block.target_type = self.canonicalize_type(&impl_block.target_type);
555 if let Some(trait_name) = &impl_block.trait_name {
556 impl_block.trait_name = Some(self.resolve_type_key(trait_name));
557 }
558 for method in &mut impl_block.methods {
559 for param in &mut method.params {
560 param.ty = self.canonicalize_type(¶m.ty);
561 }
562 if let Some(ret) = method.return_type.clone() {
563 method.return_type = Some(self.canonicalize_type(&ret));
564 }
565 }
566
567 let type_name = match &impl_block.target_type.kind {
568 TypeKind::Named(name) => self.resolve_type_key(name),
569 TypeKind::GenericInstance { name, .. } => self.resolve_type_key(name),
570 _ => {
571 return Err(self.type_error(
572 "Impl target must be a named type when registering from Rust".to_string(),
573 ))
574 }
575 };
576
577 self.env.register_impl(&impl_block);
578 for method in &impl_block.methods {
579 let params: Vec<Type> = method.params.iter().map(|p| p.ty.clone()).collect();
580 let return_type = method
581 .return_type
582 .clone()
583 .unwrap_or(Type::new(TypeKind::Unit, Span::dummy()));
584 let has_self = method.params.iter().any(|p| p.is_self);
585 let canonical_name = if method.name.contains(':') || method.name.contains('.') {
586 self.resolve_type_key(&method.name)
587 } else if has_self {
588 format!("{}:{}", type_name, method.name)
589 } else {
590 format!("{}.{}", type_name, method.name)
591 };
592 #[cfg(all(debug_assertions, feature = "std"))]
593 eprintln!(
594 "register_external_impl canonical method {} (has_self={})",
595 canonical_name, has_self
596 );
597 let signature = FunctionSignature {
598 params,
599 return_type,
600 is_method: has_self,
601 };
602 self.env
603 .register_or_update_function(canonical_name, signature)?;
604 }
605
606 Ok(())
607 }
608
609 pub fn resolve_type_key(&self, name: &str) -> String {
610 if let Some((head, tail)) = name.split_once('.') {
611 if let Some(module) = &self.current_module {
612 if let Some(imports) = self.imports_by_module.get(module) {
613 if let Some(real_module) = imports.module_aliases.get(head) {
614 if tail.is_empty() {
615 return real_module.clone();
616 } else {
617 return format!("{}.{}", real_module, tail);
618 }
619 }
620 }
621 }
622
623 return name.to_string();
624 }
625
626 if self.env.lookup_struct(name).is_some()
627 || self.env.lookup_enum(name).is_some()
628 || self.env.lookup_trait(name).is_some()
629 {
630 return name.to_string();
631 }
632
633 if self.env.is_builtin_type(name) {
634 return name.to_string();
635 }
636
637 if let Some(module) = &self.current_module {
638 if let Some(imports) = self.imports_by_module.get(module) {
639 if let Some(fq) = imports.type_aliases.get(name) {
640 return fq.clone();
641 }
642 }
643
644 return format!("{}.{}", module, name);
645 }
646
647 name.to_string()
648 }
649
650 fn register_type_definition(&mut self, item: &Item) -> Result<()> {
651 match &item.kind {
652 ItemKind::Struct(s) => {
653 let mut s2 = s.clone();
654 if let Some(module) = &self.current_module {
655 if !s2.name.contains('.') {
656 s2.name = format!("{}.{}", module, s2.name);
657 }
658 }
659
660 for field in &mut s2.fields {
661 field.ty = self.canonicalize_type(&field.ty);
662 if let Some(target) = &field.weak_target {
663 field.weak_target = Some(self.canonicalize_type(target));
664 }
665 }
666
667 self.env.register_struct(&s2)?;
668 }
669
670 ItemKind::Enum(e) => {
671 let mut e2 = e.clone();
672 if let Some(module) = &self.current_module {
673 if !e2.name.contains('.') {
674 e2.name = format!("{}.{}", module, e2.name);
675 }
676 }
677
678 for variant in &mut e2.variants {
679 if let Some(fields) = &mut variant.fields {
680 for field in fields {
681 *field = self.canonicalize_type(field);
682 }
683 }
684 }
685
686 self.env.register_enum(&e2)?;
687 }
688
689 ItemKind::Trait(t) => {
690 let mut t2 = t.clone();
691 if let Some(module) = &self.current_module {
692 if !t2.name.contains('.') {
693 t2.name = format!("{}.{}", module, t2.name);
694 }
695 }
696
697 for method in &mut t2.methods {
698 for param in &mut method.params {
699 param.ty = self.canonicalize_type(¶m.ty);
700 }
701 if let Some(ret) = method.return_type.clone() {
702 method.return_type = Some(self.canonicalize_type(&ret));
703 }
704 }
705
706 self.env.register_trait(&t2)?;
707 }
708
709 ItemKind::TypeAlias {
710 name,
711 type_params,
712 target,
713 } => {
714 let qname = if let Some(module) = &self.current_module {
715 if name.contains('.') {
716 name.clone()
717 } else {
718 format!("{}.{}", module, name)
719 }
720 } else {
721 name.clone()
722 };
723 self.env.register_type_alias(
724 qname,
725 type_params.clone(),
726 self.canonicalize_type(target),
727 )?;
728 }
729
730 ItemKind::Extern { items, .. } => {
731 for ext in items {
732 match ext {
733 ExternItem::Struct(def) => {
734 self.register_external_struct(def.clone())?;
735 }
736 ExternItem::Enum(def) => {
737 self.register_external_enum(def.clone())?;
738 }
739 ExternItem::Const { name, ty } => {
740 let key = self.resolve_value_key(name);
741 self.env
742 .register_constant(key, self.canonicalize_type(ty))?;
743 }
744 ExternItem::Function { .. } => {}
745 }
746 }
747 }
748
749 _ => {}
750 }
751
752 Ok(())
753 }
754
755 fn type_error(&self, message: String) -> LustError {
756 LustError::TypeError { message }
757 }
758
759 fn type_error_at(&self, message: String, span: Span) -> LustError {
760 if span.start_line > 0 {
761 LustError::TypeErrorWithSpan {
762 message,
763 line: span.start_line,
764 column: span.start_col,
765 module: self.current_module.clone(),
766 }
767 } else {
768 LustError::TypeError { message }
769 }
770 }
771
772 fn types_equal(&self, t1: &Type, t2: &Type) -> bool {
773 t1.kind == t2.kind
774 }
775
776 pub fn canonicalize_type(&self, ty: &Type) -> Type {
777 use crate::ast::TypeKind as TK;
778 match &ty.kind {
779 TK::Named(name) => Type::new(TK::Named(self.resolve_type_key(name)), ty.span),
780 TK::Array(inner) => {
781 Type::new(TK::Array(Box::new(self.canonicalize_type(inner))), ty.span)
782 }
783
784 TK::Tuple(elements) => Type::new(
785 TK::Tuple(elements.iter().map(|t| self.canonicalize_type(t)).collect()),
786 ty.span,
787 ),
788 TK::Option(inner) => {
789 Type::new(TK::Option(Box::new(self.canonicalize_type(inner))), ty.span)
790 }
791
792 TK::Result(ok, err) => Type::new(
793 TK::Result(
794 Box::new(self.canonicalize_type(ok)),
795 Box::new(self.canonicalize_type(err)),
796 ),
797 ty.span,
798 ),
799 TK::Map(k, v) => Type::new(
800 TK::Map(
801 Box::new(self.canonicalize_type(k)),
802 Box::new(self.canonicalize_type(v)),
803 ),
804 ty.span,
805 ),
806 TK::Ref(inner) => Type::new(TK::Ref(Box::new(self.canonicalize_type(inner))), ty.span),
807 TK::MutRef(inner) => {
808 Type::new(TK::MutRef(Box::new(self.canonicalize_type(inner))), ty.span)
809 }
810
811 TK::Pointer { mutable, pointee } => Type::new(
812 TK::Pointer {
813 mutable: *mutable,
814 pointee: Box::new(self.canonicalize_type(pointee)),
815 },
816 ty.span,
817 ),
818 _ => ty.clone(),
819 }
820 }
821
822 fn unify(&self, expected: &Type, actual: &Type) -> Result<()> {
823 let span = if actual.span.start_line > 0 {
824 Some(actual.span)
825 } else if expected.span.start_line > 0 {
826 Some(expected.span)
827 } else {
828 None
829 };
830 self.unify_at(expected, actual, span)
831 }
832
833 fn unify_at(&self, expected: &Type, actual: &Type, span: Option<Span>) -> Result<()> {
834 if matches!(expected.kind, TypeKind::Unknown) || matches!(actual.kind, TypeKind::Unknown) {
835 return Ok(());
836 }
837
838 if matches!(expected.kind, TypeKind::Infer) || matches!(actual.kind, TypeKind::Infer) {
839 return Ok(());
840 }
841
842 if self.is_lua_multi_return(expected) || self.is_lua_multi_return(actual) {
843 return Ok(());
844 }
845
846 if matches!(&expected.kind, TypeKind::Named(name) if name == "LuaValue")
847 || matches!(&actual.kind, TypeKind::Named(name) if name == "LuaValue")
848 {
849 return Ok(());
850 }
851
852 match (&expected.kind, &actual.kind) {
853 (TypeKind::Union(expected_types), TypeKind::Union(actual_types)) => {
854 if expected_types.len() != actual_types.len() {
855 return Err(self.type_error(format!(
856 "Union types have different number of members: expected {}, got {}",
857 expected_types.len(),
858 actual_types.len()
859 )));
860 }
861
862 for exp_type in expected_types {
863 let mut found = false;
864 for act_type in actual_types {
865 if self.types_equal(exp_type, act_type) {
866 found = true;
867 break;
868 }
869 }
870
871 if !found {
872 return Err(match span {
873 Some(s) => self.type_error_at(
874 format!(
875 "Union type member '{}' not found in actual union",
876 exp_type
877 ),
878 s,
879 ),
880 None => self.type_error(format!(
881 "Union type member '{}' not found in actual union",
882 exp_type
883 )),
884 });
885 }
886 }
887
888 return Ok(());
889 }
890
891 (TypeKind::Union(expected_types), _) => {
892 for union_member in expected_types {
893 if self.unify(union_member, actual).is_ok() {
894 return Ok(());
895 }
896 }
897
898 return Err(match span {
899 Some(s) => self.type_error_at(
900 format!("Type '{}' is not compatible with union type", actual),
901 s,
902 ),
903 None => self.type_error(format!(
904 "Type '{}' is not compatible with union type",
905 actual
906 )),
907 });
908 }
909
910 (_, TypeKind::Union(actual_types)) => {
911 for union_member in actual_types {
912 self.unify(expected, union_member)?;
913 }
914
915 return Ok(());
916 }
917
918 _ => {}
919 }
920
921 match (&expected.kind, &actual.kind) {
922 (TypeKind::Tuple(expected_elems), TypeKind::Tuple(actual_elems)) => {
923 if expected_elems.len() != actual_elems.len() {
924 return Err(match span {
925 Some(s) => self.type_error_at(
926 format!(
927 "Tuple length mismatch: expected {} element(s), got {}",
928 expected_elems.len(),
929 actual_elems.len()
930 ),
931 s,
932 ),
933 None => self.type_error(format!(
934 "Tuple length mismatch: expected {} element(s), got {}",
935 expected_elems.len(),
936 actual_elems.len()
937 )),
938 });
939 }
940
941 for (exp_elem, act_elem) in expected_elems.iter().zip(actual_elems.iter()) {
942 self.unify(exp_elem, act_elem)?;
943 }
944
945 return Ok(());
946 }
947
948 (TypeKind::Tuple(_), _) | (_, TypeKind::Tuple(_)) => {
949 return Err(match span {
950 Some(s) => self.type_error_at(
951 format!("Tuple type is not compatible with type '{}'", actual),
952 s,
953 ),
954 None => self.type_error(format!(
955 "Tuple type is not compatible with type '{}'",
956 actual
957 )),
958 })
959 }
960
961 (TypeKind::Named(name), TypeKind::Array(_))
962 | (TypeKind::Array(_), TypeKind::Named(name))
963 if name == "Array" =>
964 {
965 return Ok(());
966 }
967
968 (TypeKind::Array(exp_el), TypeKind::Array(act_el)) => {
969 if matches!(exp_el.kind, TypeKind::Unknown | TypeKind::Infer)
970 || matches!(act_el.kind, TypeKind::Unknown | TypeKind::Infer)
971 {
972 return Ok(());
973 } else {
974 return self.unify(exp_el, act_el);
975 }
976 }
977
978 (TypeKind::Map(exp_key, exp_value), TypeKind::Map(act_key, act_value)) => {
979 self.unify(exp_key, act_key)?;
980 return self.unify(exp_value, act_value);
981 }
982
983 (TypeKind::Named(name), TypeKind::Option(_))
984 | (TypeKind::Option(_), TypeKind::Named(name))
985 if name == "Option" =>
986 {
987 return Ok(());
988 }
989
990 (TypeKind::Option(exp_inner), TypeKind::Option(act_inner)) => {
991 if matches!(exp_inner.kind, TypeKind::Unknown | TypeKind::Infer)
992 || matches!(act_inner.kind, TypeKind::Unknown | TypeKind::Infer)
993 {
994 return Ok(());
995 } else {
996 return self.unify(exp_inner, act_inner);
997 }
998 }
999
1000 (TypeKind::Named(name), TypeKind::Result(_, _))
1001 | (TypeKind::Result(_, _), TypeKind::Named(name))
1002 if name == "Result" =>
1003 {
1004 return Ok(());
1005 }
1006
1007 (TypeKind::Result(exp_ok, exp_err), TypeKind::Result(act_ok, act_err)) => {
1008 if matches!(exp_ok.kind, TypeKind::Unknown | TypeKind::Infer)
1009 || matches!(act_ok.kind, TypeKind::Unknown | TypeKind::Infer)
1010 {
1011 if matches!(exp_err.kind, TypeKind::Unknown | TypeKind::Infer)
1012 || matches!(act_err.kind, TypeKind::Unknown | TypeKind::Infer)
1013 {
1014 return Ok(());
1015 } else {
1016 return self.unify(exp_err, act_err);
1017 }
1018 } else {
1019 self.unify(exp_ok, act_ok)?;
1020 return self.unify(exp_err, act_err);
1021 }
1022 }
1023
1024 _ => {}
1025 }
1026
1027 if self.types_equal(expected, actual) {
1028 Ok(())
1029 } else {
1030 Err(match span {
1031 Some(s) => self.type_error_at(
1032 format!("Type mismatch: expected '{}', got '{}'", expected, actual),
1033 s,
1034 ),
1035 None => self.type_error(format!(
1036 "Type mismatch: expected '{}', got '{}'",
1037 expected, actual
1038 )),
1039 })
1040 }
1041 }
1042
1043 fn types_compatible(&self, expected: &Type, actual: &Type) -> bool {
1044 if matches!(expected.kind, TypeKind::Unknown) || matches!(actual.kind, TypeKind::Unknown) {
1045 return true;
1046 }
1047
1048 if matches!(expected.kind, TypeKind::Infer) || matches!(actual.kind, TypeKind::Infer) {
1049 return true;
1050 }
1051
1052 match (&expected.kind, &actual.kind) {
1053 (TypeKind::Generic(_), TypeKind::Generic(_)) => return true,
1054 (TypeKind::Generic(_), _) | (_, TypeKind::Generic(_)) => return true,
1055 _ => {}
1056 }
1057
1058 match (&expected.kind, &actual.kind) {
1059 (TypeKind::Array(e1), TypeKind::Array(e2)) => {
1060 return self.types_compatible(e1, e2);
1061 }
1062
1063 (TypeKind::Named(name), TypeKind::Array(_))
1064 | (TypeKind::Array(_), TypeKind::Named(name))
1065 if name == "Array" =>
1066 {
1067 return true;
1068 }
1069
1070 _ => {}
1071 }
1072
1073 match (&expected.kind, &actual.kind) {
1074 (TypeKind::Map(k1, v1), TypeKind::Map(k2, v2)) => {
1075 return self.types_compatible(k1, k2) && self.types_compatible(v1, v2);
1076 }
1077
1078 _ => {}
1079 }
1080
1081 match (&expected.kind, &actual.kind) {
1082 (TypeKind::Option(t1), TypeKind::Option(t2)) => {
1083 return self.types_compatible(t1, t2);
1084 }
1085
1086 (TypeKind::Named(name), TypeKind::Option(_))
1087 | (TypeKind::Option(_), TypeKind::Named(name))
1088 if name == "Option" =>
1089 {
1090 return true;
1091 }
1092
1093 _ => {}
1094 }
1095
1096 match (&expected.kind, &actual.kind) {
1097 (TypeKind::Result(ok1, err1), TypeKind::Result(ok2, err2)) => {
1098 return self.types_compatible(ok1, ok2) && self.types_compatible(err1, err2);
1099 }
1100
1101 (TypeKind::Named(name), TypeKind::Result(_, _))
1102 | (TypeKind::Result(_, _), TypeKind::Named(name))
1103 if name == "Result" =>
1104 {
1105 return true;
1106 }
1107
1108 _ => {}
1109 }
1110
1111 match (&expected.kind, &actual.kind) {
1112 (
1113 TypeKind::Function {
1114 params: p1,
1115 return_type: r1,
1116 },
1117 TypeKind::Function {
1118 params: p2,
1119 return_type: r2,
1120 },
1121 ) => {
1122 if p1.len() != p2.len() {
1123 return false;
1124 }
1125
1126 for (t1, t2) in p1.iter().zip(p2.iter()) {
1127 if !self.types_compatible(t1, t2) {
1128 return false;
1129 }
1130 }
1131
1132 return self.types_compatible(r1, r2);
1133 }
1134
1135 _ => {}
1136 }
1137
1138 self.types_equal(expected, actual)
1139 }
1140
1141 fn unify_with_bounds(&self, expected: &Type, actual: &Type) -> Result<()> {
1142 if let TypeKind::Generic(type_param) = &expected.kind {
1143 if let Some(trait_names) = self.current_trait_bounds.get(type_param) {
1144 for trait_name in trait_names {
1145 if !self.env.type_implements_trait(actual, trait_name) {
1146 return Err(self.type_error(format!(
1147 "Type '{}' does not implement required trait '{}'",
1148 actual, trait_name
1149 )));
1150 }
1151 }
1152
1153 return Ok(());
1154 }
1155
1156 return Ok(());
1157 }
1158
1159 self.unify(expected, actual)
1160 }
1161
1162 fn is_lua_multi_return(&self, ty: &Type) -> bool {
1163 if let TypeKind::Array(inner) = &ty.kind {
1164 return matches!(inner.kind, TypeKind::Unknown)
1165 || matches!(&inner.kind, TypeKind::Named(name) if name == "LuaValue");
1166 }
1167 false
1168 }
1169
1170 fn record_short_circuit_info(&mut self, span: Span, info: &ShortCircuitInfo) {
1171 let truthy = info.truthy.as_ref().map(|ty| self.canonicalize_type(ty));
1172 let falsy = info.falsy.as_ref().map(|ty| self.canonicalize_type(ty));
1173 let option_inner = info
1174 .option_inner
1175 .as_ref()
1176 .map(|ty| self.canonicalize_type(ty));
1177 let module_key = self.current_module_key();
1178 self.short_circuit_info
1179 .entry(module_key)
1180 .or_default()
1181 .insert(
1182 span,
1183 ShortCircuitInfo {
1184 truthy,
1185 falsy,
1186 option_inner,
1187 },
1188 );
1189 }
1190
1191 fn short_circuit_profile(&self, expr: &Expr, ty: &Type) -> ShortCircuitInfo {
1192 let module_key = self
1193 .current_module
1194 .as_ref()
1195 .map(String::as_str)
1196 .unwrap_or("");
1197 if let Some(module_map) = self.short_circuit_info.get(module_key) {
1198 if let Some(info) = module_map.get(&expr.span) {
1199 return info.clone();
1200 }
1201 }
1202
1203 ShortCircuitInfo {
1204 truthy: if self.type_can_be_truthy(ty) {
1205 Some(self.canonicalize_type(ty))
1206 } else {
1207 None
1208 },
1209 falsy: self.extract_falsy_type(ty),
1210 option_inner: None,
1211 }
1212 }
1213
1214 fn current_module_key(&self) -> String {
1215 self.current_module
1216 .as_ref()
1217 .cloned()
1218 .unwrap_or_else(|| "".to_string())
1219 }
1220
1221 fn clear_option_for_span(&mut self, span: Span) {
1222 let module_key = self.current_module_key();
1223 if let Some(module_map) = self.short_circuit_info.get_mut(&module_key) {
1224 if let Some(info) = module_map.get_mut(&span) {
1225 info.option_inner = None;
1226 }
1227 }
1228 }
1229
1230 fn type_can_be_truthy(&self, ty: &Type) -> bool {
1231 match &ty.kind {
1232 TypeKind::Union(members) => {
1233 members.iter().any(|member| self.type_can_be_truthy(member))
1234 }
1235 TypeKind::Bool => true,
1236 TypeKind::Unknown => true,
1237 _ => true,
1238 }
1239 }
1240
1241 fn type_can_be_falsy(&self, ty: &Type) -> bool {
1242 match &ty.kind {
1243 TypeKind::Union(members) => members.iter().any(|member| self.type_can_be_falsy(member)),
1244 TypeKind::Bool => true,
1245 TypeKind::Unknown => true,
1246 TypeKind::Option(_) => true,
1247 _ => false,
1248 }
1249 }
1250
1251 fn extract_falsy_type(&self, ty: &Type) -> Option<Type> {
1252 match &ty.kind {
1253 TypeKind::Bool => Some(Type::new(TypeKind::Bool, ty.span)),
1254 TypeKind::Unknown => Some(Type::new(TypeKind::Unknown, ty.span)),
1255 TypeKind::Option(inner) => Some(Type::new(
1256 TypeKind::Option(Box::new(self.canonicalize_type(inner))),
1257 ty.span,
1258 )),
1259 TypeKind::Union(members) => {
1260 let mut parts = Vec::new();
1261 for member in members {
1262 if let Some(part) = self.extract_falsy_type(member) {
1263 parts.push(part);
1264 }
1265 }
1266 self.merge_optional_types(parts)
1267 }
1268 _ => None,
1269 }
1270 }
1271
1272 fn merge_optional_types(&self, types: Vec<Type>) -> Option<Type> {
1273 if types.is_empty() {
1274 return None;
1275 }
1276
1277 Some(self.make_union_from_types(types))
1278 }
1279
1280 fn make_union_from_types(&self, types: Vec<Type>) -> Type {
1281 let mut flat: Vec<Type> = Vec::new();
1282 for ty in types {
1283 let canonical = self.canonicalize_type(&ty);
1284 match &canonical.kind {
1285 TypeKind::Union(members) => {
1286 for member in members {
1287 self.push_unique_type(&mut flat, member.clone());
1288 }
1289 }
1290 _ => self.push_unique_type(&mut flat, canonical),
1291 }
1292 }
1293
1294 match flat.len() {
1295 0 => Type::new(TypeKind::Unknown, Self::dummy_span()),
1296 1 => flat.into_iter().next().unwrap(),
1297 _ => Type::new(TypeKind::Union(flat), Self::dummy_span()),
1298 }
1299 }
1300
1301 fn push_unique_type(&self, list: &mut Vec<Type>, candidate: Type) {
1302 if !list
1303 .iter()
1304 .any(|existing| self.types_equal(existing, &candidate))
1305 {
1306 list.push(candidate);
1307 }
1308 }
1309
1310 fn combine_truthy_falsy(&self, truthy: Option<Type>, falsy: Option<Type>) -> Type {
1311 match (truthy, falsy) {
1312 (Some(t), Some(f)) => self.make_union_from_types(vec![t, f]),
1313 (Some(t), None) => t,
1314 (None, Some(f)) => f,
1315 (None, None) => Type::new(TypeKind::Unknown, Self::dummy_span()),
1316 }
1317 }
1318
1319 fn is_bool_like(&self, ty: &Type) -> bool {
1320 match &ty.kind {
1321 TypeKind::Bool => true,
1322 TypeKind::Union(members) => members.iter().all(|member| self.is_bool_like(member)),
1323 _ => false,
1324 }
1325 }
1326
1327 fn option_inner_type<'a>(&self, ty: &'a Type) -> Option<&'a Type> {
1328 match &ty.kind {
1329 TypeKind::Option(inner) => Some(inner.as_ref()),
1330 TypeKind::Union(members) => {
1331 for member in members {
1332 if let Some(inner) = self.option_inner_type(member) {
1333 return Some(inner);
1334 }
1335 }
1336 None
1337 }
1338 _ => None,
1339 }
1340 }
1341
1342 fn should_optionize(&self, left: &Type, right: &Type) -> bool {
1343 self.is_bool_like(left)
1344 && !self.is_bool_like(right)
1345 && self.option_inner_type(right).is_none()
1346 }
1347}