1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
//! Type-substitution and field/method/function return-type lookups shared
//! across the rest of the expression-lowering submodules.
use crate::ast::PrimitiveType;
use crate::error::CompilerError;
use crate::ir::lower::IrLowerer;
use crate::ir::{IrExpr, ResolvedType};
use std::collections::HashMap;
/// Substitute `TypeParam(name)` references inside `ty` using `subs`.
/// Used by `resolve_method_return_type` when the receiver is a
/// `Generic { base, args }` so the impl method's return type
/// (declared in terms of the struct's generic params) gets the
/// concrete instantiation's type arguments.
fn substitute_typeparam_in_resolved(ty: &mut ResolvedType, subs: &HashMap<String, ResolvedType>) {
match ty {
ResolvedType::TypeParam(name) => {
if let Some(concrete) = subs.get(name) {
*ty = concrete.clone();
}
}
ResolvedType::Array(inner) | ResolvedType::Range(inner) | ResolvedType::Optional(inner) => {
substitute_typeparam_in_resolved(inner, subs);
}
ResolvedType::Tuple(fields) => {
for (_, t) in fields {
substitute_typeparam_in_resolved(t, subs);
}
}
ResolvedType::Dictionary { key_ty, value_ty } => {
substitute_typeparam_in_resolved(key_ty, subs);
substitute_typeparam_in_resolved(value_ty, subs);
}
ResolvedType::Closure {
param_tys,
return_ty,
} => {
for (_, t) in param_tys {
substitute_typeparam_in_resolved(t, subs);
}
substitute_typeparam_in_resolved(return_ty, subs);
}
ResolvedType::Generic { args, .. } => {
for a in args {
substitute_typeparam_in_resolved(a, subs);
}
}
ResolvedType::External { type_args, .. } => {
for a in type_args {
substitute_typeparam_in_resolved(a, subs);
}
}
ResolvedType::Primitive(_)
| ResolvedType::Struct(_)
| ResolvedType::Trait(_)
| ResolvedType::Enum(_)
| ResolvedType::Error => {}
}
}
impl IrLowerer<'_> {
/// Resolve the type of a field access on an expression.
///
/// Handles struct field access by looking up the field in the struct
/// definition. Anything the semantic layer should have caught that
/// still reaches here (missing field, field access on a non-struct
/// type) records an `InternalError` so compilation fails loudly.
pub(super) fn resolve_field_type(
&mut self,
object_ty: &ResolvedType,
field_name: &str,
) -> ResolvedType {
match object_ty {
ResolvedType::Struct(struct_id) => {
if let Some(struct_def) = self.module.get_struct(*struct_id) {
for field in &struct_def.fields {
if field.name == field_name {
return field.ty.clone();
}
}
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: struct `{}` has no field `{field_name}`",
struct_def.name
),
span: self.current_span,
});
} else {
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: struct id {} out of bounds during field access `{field_name}`",
struct_id.0
),
span: self.current_span,
});
}
ResolvedType::Primitive(PrimitiveType::Never)
}
ResolvedType::Primitive(_)
| ResolvedType::Trait(_)
| ResolvedType::Enum(_)
| ResolvedType::Array(_)
| ResolvedType::Range(_)
| ResolvedType::Optional(_)
| ResolvedType::Tuple(_)
| ResolvedType::Generic { .. }
| ResolvedType::TypeParam(_)
| ResolvedType::External { .. }
| ResolvedType::Dictionary { .. }
| ResolvedType::Closure { .. } => {
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: cannot access field `{field_name}` on non-struct receiver {object_ty:?}"
),
span: self.current_span,
});
ResolvedType::Primitive(PrimitiveType::Never)
}
// Receiver was already an upstream error; the original
// `CompilerError` has been recorded — propagate without cascading.
ResolvedType::Error => ResolvedType::Error,
}
}
/// Resolve the return type of a method call.
///
/// Looks up user-defined methods in impl blocks. Records an
/// `InternalError` when the method cannot be resolved on a concrete
/// receiver — those cases should have been caught by semantic
/// analysis and reaching here indicates a compiler bug.
#[expect(
clippy::too_many_lines,
reason = "exhaustive resolution: pre-installed methods, struct/enum/Generic/TypeParam/Trait dispatch arms"
)]
pub(super) fn resolve_method_return_type(
&mut self,
receiver_ty: &ResolvedType,
method_name: &str,
) -> ResolvedType {
// If we are mid-lowering an impl block, its method set is recorded
// in `current_impl_method_returns`. Forward references like
// `self.other()` resolve against that map before the impl is
// installed into `module.impls`.
if let Some(returns) = &self.current_impl_method_returns {
if let Some(entry) = returns.get(method_name) {
return entry
.clone()
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
if let ResolvedType::Struct(struct_id) = receiver_ty {
for impl_block in &self.module.impls {
if impl_block.struct_id() == Some(*struct_id) {
for func in &impl_block.functions {
if func.name == method_name {
return func
.return_type
.clone()
.or_else(|| func.body.as_ref().map(|b| b.ty().clone()))
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
}
}
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: no impl method `{method_name}` for struct id {}",
struct_id.0
),
span: self.current_span,
});
return ResolvedType::Primitive(PrimitiveType::Never);
}
// Generic receiver (`Box<I32>`): look up the impl on the
// generic base, then substitute the impl method's TypeParams
// with the concrete type arguments.
if let ResolvedType::Generic { base, args } = receiver_ty {
let (target_struct_id, target_enum_id) = match base {
crate::ir::GenericBase::Struct(id) => (Some(*id), None),
crate::ir::GenericBase::Enum(id) => (None, Some(*id)),
// A trait base wouldn't appear here as a method-call
// receiver post item E2. Skip and fall through.
crate::ir::GenericBase::Trait(_) => (None, None),
};
let generic_params: Vec<String> = if let Some(sid) = target_struct_id {
self.module
.get_struct(sid)
.map(|s| s.generic_params.iter().map(|p| p.name.clone()).collect())
.unwrap_or_default()
} else if let Some(eid) = target_enum_id {
self.module
.get_enum(eid)
.map(|e| e.generic_params.iter().map(|p| p.name.clone()).collect())
.unwrap_or_default()
} else {
Vec::new()
};
for impl_block in &self.module.impls {
let matches_target = match impl_block.target {
crate::ir::ImplTarget::Struct(id) => Some(id) == target_struct_id,
crate::ir::ImplTarget::Enum(id) => Some(id) == target_enum_id,
crate::ir::ImplTarget::Primitive(_) => false,
};
if !matches_target {
continue;
}
for func in &impl_block.functions {
if func.name == method_name {
let mut ret = func
.return_type
.clone()
.or_else(|| func.body.as_ref().map(|b| b.ty().clone()))
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
let subs: HashMap<String, ResolvedType> = generic_params
.iter()
.cloned()
.zip(args.iter().cloned())
.collect();
substitute_typeparam_in_resolved(&mut ret, &subs);
return ret;
}
}
}
}
if let ResolvedType::Primitive(prim) = receiver_ty {
for impl_block in &self.module.impls {
if matches!(impl_block.target, crate::ir::ImplTarget::Primitive(p) if p == *prim) {
for func in &impl_block.functions {
if func.name == method_name {
return func
.return_type
.clone()
.or_else(|| func.body.as_ref().map(|b| b.ty().clone()))
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
}
}
// Fall through to the catch-all error: a missing primitive
// method is a compiler bug.
}
if let ResolvedType::Enum(enum_id) = receiver_ty {
for impl_block in &self.module.impls {
if impl_block.enum_id() == Some(*enum_id) {
for func in &impl_block.functions {
if func.name == method_name {
return func
.return_type
.clone()
.or_else(|| func.body.as_ref().map(|b| b.ty().clone()))
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
}
}
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: no impl method `{method_name}` for enum id {}",
enum_id.0
),
span: self.current_span,
});
return ResolvedType::Primitive(PrimitiveType::Never);
}
// TypeParam (generic parameter) or Trait receiver: look up the
// method's return type on any trait declaring it. Semantic analysis
// has already verified the bound is in scope.
if let ResolvedType::TypeParam(name) = receiver_ty {
if let Some(trait_id) = self.find_trait_for_method(name, method_name) {
if let Some(trait_def) = self.module.get_trait(trait_id) {
if let Some(sig) = trait_def.methods.iter().find(|m| m.name == method_name) {
return sig
.return_type
.clone()
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
}
}
if let ResolvedType::Trait(trait_id) = receiver_ty {
if let Some(trait_def) = self.module.get_trait(*trait_id) {
if let Some(sig) = trait_def.methods.iter().find(|m| m.name == method_name) {
return sig
.return_type
.clone()
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
}
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: cannot resolve return type of `{method_name}` on receiver {receiver_ty:?}"
),
span: self.current_span,
});
ResolvedType::Primitive(PrimitiveType::Never)
}
/// Resolve the return type of a function call.
///
/// Looks first in the already-lowered IR (`module.functions`), then
/// falls back to the semantic symbol table so forward references to
/// functions declared later in the file resolve to their declared
/// return types. Records an `InternalError` only when neither source
/// has an entry — in that case semantic analysis has missed the
/// reference, which is a compiler bug.
pub(super) fn resolve_function_return_type(
&mut self,
fn_name: &str,
_args: &[(Option<String>, IrExpr)],
) -> ResolvedType {
if let Some(func_id) = self.module.function_id(fn_name) {
if let Some(func) = self.module.get_function(func_id) {
return func
.return_type
.clone()
.or_else(|| func.body.as_ref().map(|b| b.ty().clone()))
.unwrap_or(ResolvedType::Primitive(PrimitiveType::Never));
}
}
if let Some(info) = self.symbols.get_function(fn_name) {
return info
.return_type
.as_ref()
.map_or(ResolvedType::Primitive(PrimitiveType::Never), |t| {
self.lower_type(t)
});
}
self.errors.push(CompilerError::InternalError {
detail: format!(
"IR lowering: unknown function `{fn_name}` reached codegen — should have been caught by semantic analysis"
),
span: self.current_span,
});
ResolvedType::Primitive(PrimitiveType::Never)
}
}