v2 / vlib / v / checker / struct.v
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1// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
2// Use of this source code is governed by an MIT license that can be found in the LICENSE file.
3module checker
4
5import v.ast
6import v.util
7import v.token
8
9fn (c &Checker) can_be_embedded_in_struct(typ ast.Type) bool {
10 return c.table.final_sym(typ).kind in [.struct, .function]
11}
12
13fn (c &Checker) is_opaque_c_typedef_struct_alias(typ ast.Type) bool {
14 sym := c.table.sym(typ)
15 if sym.kind != .alias {
16 return false
17 }
18 final_sym := c.table.final_sym(typ)
19 if final_sym.language != .c || final_sym.kind != .struct {
20 return false
21 }
22 if final_sym.info is ast.Struct {
23 return final_sym.info.is_typedef && final_sym.info.is_empty_struct()
24 }
25 return false
26}
27
28fn (mut c Checker) struct_decl(mut node ast.StructDecl) {
29 util.timing_start(@METHOD)
30 defer {
31 util.timing_measure_cumulative(@METHOD)
32 }
33 if node.language in [.c, .js] && node.generic_types.len > 0 {
34 lang := if node.language == .c { 'C' } else { 'JS' }
35 c.error('${lang} structs cannot be declared as generic', node.pos)
36 }
37 node_name := if node.scoped_name != '' { node.scoped_name } else { node.name }
38 mut struct_sym, struct_typ_idx := c.table.find_sym_and_type_idx(node_name)
39 node.idx = struct_typ_idx
40 mut has_generic_types := false
41 if mut struct_sym.info is ast.Struct {
42 for mut symfield in struct_sym.info.fields {
43 symfield.container_typ = struct_typ_idx
44 if struct_sym.info.is_union {
45 symfield.is_part_of_union = true
46 }
47 }
48
49 if node.language == .v && !c.is_builtin_mod && !struct_sym.info.is_anon {
50 c.check_valid_pascal_case(node.name, 'struct name', node.pos)
51 }
52 if node.language == .v {
53 for embed in node.embeds {
54 embed_typ := c.table.unaliased_type(embed.typ)
55 if embed_typ.is_ptr() || embed_typ.has_flag(.option) {
56 continue
57 }
58 embed_sym := c.table.sym(embed_typ)
59 if embed_sym.name == struct_sym.name
60 || c.table.has_deep_child_no_ref(embed_sym, struct_sym.name) {
61 c.error('invalid recursive struct `${node.name}`', node.pos)
62 break
63 }
64 }
65 }
66 for embed in node.embeds {
67 // gotodef for embedded struct types
68 if c.pref.is_vls && c.pref.linfo.method == .definition {
69 if c.vls_is_the_node(embed.pos) {
70 embed_sym := c.table.sym(embed.typ)
71 pos := embed_sym.info.get_name_pos() or { token.Pos{} }
72 if pos.file_idx != -1 {
73 println('${c.table.filelist[pos.file_idx]}:${pos.line_nr + 1}:${pos.col}')
74 exit(0)
75 }
76 }
77 }
78 embed_sym := c.table.sym(embed.typ)
79 embed_final_sym := c.table.final_sym(embed.typ)
80 if embed_sym.info is ast.Alias {
81 parent_sym := c.table.final_sym(embed_sym.info.parent_type)
82 if parent_sym.kind !in [.struct, .function] {
83 c.error('`${embed_sym.name}` (alias of `${parent_sym.name}`) is not a struct',
84 embed.pos)
85 }
86 } else if embed_sym.kind !in [.struct, .function] {
87 c.error('`${embed_sym.name}` is not a struct', embed.pos)
88 } else if embed_final_sym.kind == .struct
89 && (embed_final_sym.info as ast.Struct).is_heap && !embed.typ.is_ptr() {
90 struct_sym.info.is_heap = true
91 }
92 embed_is_generic := embed.typ.has_flag(.generic)
93 if embed_is_generic {
94 has_generic_types = true
95 }
96 // Ensure each generic type of the embed was declared in the struct's definition
97 if embed_is_generic && node.generic_types.len > 0 {
98 embed_generic_names := c.table.generic_type_names(embed.typ)
99 node_generic_names := node.generic_types.map(c.table.type_to_str(it))
100 for name in embed_generic_names {
101 if name !in node_generic_names {
102 struct_generic_names := node_generic_names.join(', ')
103 c.error('generic type name `${name}` is not mentioned in struct `${node.name}[${struct_generic_names}]`',
104 embed.pos)
105 }
106 }
107 }
108 }
109 if struct_sym.info.is_minify && !c.pref.output_cross_c {
110 node.fields.sort_with_compare(minify_sort_fn)
111 struct_sym.info.fields.sort_with_compare(minify_sort_fn)
112 }
113 for attr in node.attrs {
114 if node.language != .c && attr.name == 'typedef' {
115 c.error('`typedef` attribute can only be used with C structs', node.pos)
116 }
117 }
118
119 // Evaluate the size of the unresolved fixed array
120 for mut field in node.fields {
121 sym := c.table.sym(field.typ)
122 if sym.info is ast.ArrayFixed && c.array_fixed_has_unresolved_size(sym.info) {
123 mut size_expr := unsafe { sym.info.size_expr }
124 old_typ := field.typ
125 field.typ = c.eval_array_fixed_sizes(mut size_expr, 0, sym.info.elem_type)
126 for mut symfield in struct_sym.info.fields {
127 if symfield.name == field.name {
128 symfield.typ = field.typ
129 }
130 }
131 // Overwrite the previously unresolved type symbol so that earlier
132 // expressions which captured its idx (e.g. IndexExpr.left_type from
133 // another file checked first) observe the resolved size. See #27078.
134 // Skip for generic structs: the size expression may reference a generic
135 // type parameter (e.g. `sizeof(T)`), which resolves to a placeholder size
136 // here; the correct per-instantiation size is computed later in struct_init.
137 if old_typ.idx() != field.typ.idx() && struct_sym.info.generic_types.len == 0 {
138 new_sym := c.table.sym(field.typ)
139 mut old_sym := c.table.type_symbols[old_typ.idx()]
140 old_sym.name = new_sym.name
141 old_sym.cname = new_sym.cname
142 old_sym.info = new_sym.info
143 }
144 }
145 }
146
147 // Update .default_expr_typ for all fields in the struct:
148 util.timing_start('Checker.struct setting default_expr_typ')
149 old_expected_type := c.expected_type
150 for mut field in node.fields {
151 // when the field has the same type that the struct itself (recursive)
152 if field.typ.clear_flag(.option).set_nr_muls(0) == struct_typ_idx {
153 for mut symfield in struct_sym.info.fields {
154 if symfield.name == field.name {
155 // only ?&Struct is allowed to be recursive
156 if field.typ.is_ptr() {
157 symfield.is_recursive = true
158 } else {
159 c.error('recursive struct is only possible with optional pointer (e.g. ?&${c.table.type_to_str(field.typ.clear_flag(.option))})',
160 field.pos)
161 }
162 }
163 }
164 }
165 // Do not allow uninitialized `fn` fields, or force `?fn`
166 // (allow them in `C.` structs)
167 if !c.is_builtin_mod && node.language == .v {
168 if !(c.file.is_translated || c.pref.translated) {
169 sym := c.table.sym(field.typ)
170 if sym.kind == .function && !field.typ.has_flag(.option)
171 && !field.has_default_expr && !field.attrs.contains('required') {
172 error_msg := 'uninitialized `fn` struct fields are not allowed, since they can result in segfaults; use `?fn` or `@[required]` or initialize the field with `=` (if you absolutely want to have unsafe function pointers, use `= unsafe { nil }`)'
173 c.note(error_msg, field.pos)
174 }
175 }
176 }
177
178 if field.has_default_expr {
179 c.expected_type = field.typ
180 field.default_expr_typ = c.expr(mut field.default_expr)
181 if field.typ.is_ptr() != field.default_expr_typ.is_ptr()
182 && field.default_expr_typ.idx() !in ast.pointer_type_idxs {
183 default_pos := field.default_expr.pos()
184 if field.default_expr is ast.CallExpr {
185 err_desc := if field.typ.is_ptr() { 'is' } else { 'is not' }
186 val_desc := if field.default_expr_typ.is_ptr() { 'is' } else { 'is not' }
187 c.error('field ${err_desc} reference but default value ${val_desc} reference',
188 default_pos)
189 } else if field.default_expr is ast.StructInit
190 || (field.typ.is_ptr() && (field.default_expr is ast.Ident
191 || field.default_expr is ast.SelectorExpr)) {
192 c.error('reference field must be initialized with reference', default_pos)
193 }
194 }
195
196 if c.table.final_sym(field.typ).kind == .voidptr
197 && field.default_expr_typ !in [ast.nil_type, ast.voidptr_type, ast.byteptr_type]
198 && !field.default_expr_typ.is_ptr()
199 && (field.default_expr !is ast.IntegerLiteral
200 || (field.default_expr is ast.IntegerLiteral
201 && field.default_expr.val.int() != 0)) {
202 c.note('voidptr variables may only be assigned voidptr values (e.g. unsafe { voidptr(${field.default_expr.str()}) })',
203 field.default_expr.pos())
204 }
205
206 // disallow map `mut a = b`
207 field_sym := c.table.sym(field.typ)
208 expr_sym := c.table.sym(field.default_expr_typ)
209 if field_sym.kind == .map && expr_sym.kind == .map && field.default_expr.is_lvalue()
210 && field.is_mut
211 && (!field.default_expr_typ.is_ptr() || field.default_expr is ast.Ident) {
212 c.error('cannot copy map: call `clone` method (or use a reference)',
213 field.default_expr.pos())
214 }
215 if c.is_nocopy_struct(field.typ) && c.is_nocopy_struct(field.default_expr_typ)
216 && field.default_expr !is ast.StructInit {
217 c.error('cannot copy @[nocopy] struct: use a reference instead',
218 field.default_expr.pos())
219 }
220 for mut symfield in struct_sym.info.fields {
221 if symfield.name == field.name {
222 symfield.default_expr_typ = field.default_expr_typ
223 break
224 }
225 }
226 }
227 // check anon struct declaration
228 if field.anon_struct_decl.fields.len > 0 {
229 c.struct_decl(mut field.anon_struct_decl)
230 }
231 }
232 c.expected_type = old_expected_type
233 util.timing_measure_cumulative('Checker.struct setting default_expr_typ')
234
235 for i, field in node.fields {
236 if field.typ.has_flag(.result) {
237 c.error('struct field does not support storing Result', field.option_pos)
238 }
239 if !c.ensure_type_exists(field.typ, field.type_pos) {
240 continue
241 }
242 if node.language == .v && !field.typ.is_ptr()
243 && c.is_opaque_c_typedef_struct_alias(field.typ) {
244 field_typ := c.table.type_to_str(field.typ)
245 ref_typ := c.table.type_to_str(field.typ.clear_option_and_result().set_nr_muls(1))
246 c.error('cannot use opaque C struct `${field_typ}` as a non-reference struct field; use `${ref_typ}` instead',
247 field.type_pos)
248 continue
249 }
250 // gotodef for struct field types
251 if c.pref.is_vls && c.pref.linfo.method == .definition {
252 if c.vls_is_the_node(field.type_pos) {
253 sym := c.table.sym(field.typ)
254 elem_type := match sym.kind {
255 .array {
256 (sym.info as ast.Array).elem_type
257 }
258 .array_fixed {
259 (sym.info as ast.ArrayFixed).elem_type
260 }
261 else {
262 ast.Type(0)
263 }
264 }
265
266 if elem_type == 0 {
267 pos := sym.info.get_name_pos() or { token.Pos{} }
268 if pos.file_idx != -1 {
269 println('${c.table.filelist[pos.file_idx]}:${pos.line_nr + 1}:${pos.col}')
270 exit(0)
271 }
272 } else {
273 elem_sym := c.table.sym(elem_type)
274 if np := elem_sym.info.get_name_pos() {
275 if np.file_idx != -1 {
276 println('${c.table.filelist[np.file_idx]}:${np.line_nr + 1}:${np.col}')
277 exit(0)
278 }
279 }
280 }
281 }
282 }
283 field_is_generic := field.typ.has_flag(.generic)
284 if c.table.type_kind(field.typ) != .alias
285 && !c.ensure_generic_type_specify_type_names(field.typ, field.type_pos, c.table.final_sym(field.typ).kind in [.array, .array_fixed, .map], field_is_generic) {
286 continue
287 }
288 if field_is_generic {
289 has_generic_types = true
290 }
291 if node.language == .v {
292 c.check_valid_snake_case(field.name, 'field name', field.pos)
293 }
294 sym := c.table.sym(field.typ)
295 field_name, field_name_len := field.name, field.name.len
296 for j in 0 .. i {
297 if field_name_len == node.fields[j].name.len && field_name == node.fields[j].name {
298 c.error('field name `${field.name}` duplicate', field.pos)
299 }
300 }
301 if field.typ != 0 {
302 if !field.typ.is_ptr() {
303 if c.table.unaliased_type(field.typ) == struct_typ_idx {
304 c.error('field `${field.name}` is part of `${node.name}`, they can not both have the same type',
305 field.type_pos)
306 }
307 }
308 }
309 match sym.kind {
310 .struct {
311 info := sym.info as ast.Struct
312 if info.is_heap && !field.typ.is_ptr() {
313 struct_sym.info.is_heap = true
314 }
315 for ct in info.concrete_types {
316 ct_sym := c.table.sym(ct)
317 if ct_sym.kind == .placeholder {
318 c.error('unknown type `${ct_sym.name}`', field.type_pos)
319 }
320 }
321 }
322 .multi_return {
323 c.error('cannot use multi return as field type', field.type_pos)
324 }
325 .none {
326 c.error('cannot use `none` as field type', field.type_pos)
327 }
328 .map {
329 info := sym.map_info()
330 if info.value_type.has_flag(.result) {
331 c.error('cannot use Result type as map value type', field.type_pos)
332 }
333 }
334 .alias {
335 if sym.name == 'byte' {
336 c.error('byte is deprecated, use u8 instead', field.type_pos)
337 }
338 }
339 else {
340 c.check_any_type(field.typ, sym, field.type_pos)
341 }
342 }
343
344 if field.has_default_expr {
345 c.expected_type = field.typ
346 if !field.typ.has_option_or_result() {
347 c.check_expr_option_or_result_call(field.default_expr, field.default_expr_typ)
348 }
349 if sym.info is ast.ArrayFixed && field.typ == field.default_expr_typ {
350 if sym.info.size_expr is ast.ComptimeCall {
351 // field [$d('x' ,2)]int = [1 ,2]!
352 if sym.info.size_expr.kind == .d {
353 c.error('cannot initialize a fixed size array field that uses `\$d()` as size quantifier since the size may change via -d',
354 field.default_expr.pos())
355 }
356 }
357 }
358 if field.default_expr is ast.ArrayInit {
359 if c.table.final_sym(field.default_expr_typ).kind in [.array, .array_fixed]
360 && c.table.value_type(field.default_expr_typ) == struct_typ_idx {
361 c.error('cannot initialize array of same struct type that is being defined (recursion detected)',
362 field.pos)
363 }
364 }
365 interface_implemented := sym.kind == .interface
366 && c.type_implements(field.default_expr_typ, field.typ, field.pos)
367 c.check_expected(field.default_expr_typ, field.typ) or {
368 if sym.kind == .interface && interface_implemented {
369 if !c.inside_unsafe && !field.default_expr_typ.is_any_kind_of_pointer() {
370 if c.table.sym(field.default_expr_typ).kind != .interface {
371 c.mark_as_referenced(mut &node.fields[i].default_expr, true)
372 }
373 }
374 } else if c.table.final_sym(field.typ).kind == .function
375 && field.default_expr_typ.is_pointer() {
376 continue
377 } else {
378 c.error('incompatible initializer for field `${field.name}`: ${err.msg()}',
379 field.default_expr.pos())
380 }
381 }
382 if field.default_expr.is_nil() {
383 mut nil_field_typ := field.typ
384 mut nil_field_sym := c.table.sym(nil_field_typ)
385 // Preserve pointer indirections while resolving alias chains.
386 for {
387 if mut nil_field_sym.info is ast.Alias {
388 parent_typ := nil_field_sym.info.parent_type
389 nil_field_typ = parent_typ.set_nr_muls(parent_typ.nr_muls() +
390 nil_field_typ.nr_muls())
391 nil_field_sym = c.table.sym(nil_field_typ)
392 } else {
393 break
394 }
395 }
396 if !nil_field_typ.is_any_kind_of_pointer() && nil_field_sym.kind != .function {
397 c.error('cannot assign `nil` to a non-pointer field', field.type_pos)
398 }
399 }
400 // Check for unnecessary inits like ` = 0` and ` = ''`
401 if field.typ.is_ptr() {
402 if field.default_expr is ast.IntegerLiteral {
403 if !c.inside_unsafe && !c.is_builtin_mod && field.default_expr.val == '0' {
404 c.error('default value of `0` for references can only be used inside `unsafe`',
405 field.default_expr.pos)
406 }
407 }
408 field_is_option := field.typ.has_flag(.option)
409 if field_is_option {
410 if field.default_expr is ast.None {
411 c.warn('unnecessary default value of `none`: struct fields are zeroed by default',
412 field.default_expr.pos)
413 } else if field.default_expr.is_nil() {
414 c.error('cannot assign `nil` to option value', field.default_expr.pos())
415 }
416 }
417 continue
418 }
419 if field.typ in ast.unsigned_integer_type_idxs {
420 if field.default_expr is ast.IntegerLiteral {
421 if field.default_expr.val[0] == `-` {
422 c.error('cannot assign negative value to unsigned integer type',
423 field.default_expr.pos)
424 }
425 }
426 }
427 if field.typ.has_flag(.option) {
428 if field.default_expr is ast.None {
429 c.warn('unnecessary default value of `none`: struct fields are zeroed by default',
430 field.default_expr.pos)
431 }
432 } else if field.typ.has_flag(.result) {
433 // struct field does not support result. Nothing to do
434 } else {
435 match field.default_expr {
436 ast.IntegerLiteral {
437 if field.default_expr.val == '0' {
438 c.warn('unnecessary default value of `0`: struct fields are zeroed by default',
439 field.default_expr.pos)
440 }
441 }
442 ast.StringLiteral {
443 if field.default_expr.val == '' {
444 c.warn("unnecessary default value of '': struct fields are zeroed by default",
445 field.default_expr.pos)
446 }
447 }
448 ast.BoolLiteral {
449 if field.default_expr.val == false {
450 c.warn('unnecessary default value `false`: struct fields are zeroed by default',
451 field.default_expr.pos)
452 }
453 }
454 else {}
455 }
456 }
457 }
458 // Ensure each generic type of the field was declared in the struct's definition
459 if node.generic_types.len > 0 && field.typ.has_flag(.generic) {
460 field_generic_names := c.table.generic_type_names(field.typ)
461 node_generic_names := node.generic_types.map(c.table.type_to_str(it))
462 for name in field_generic_names {
463 if name !in node_generic_names {
464 struct_generic_names := node_generic_names.join(', ')
465 c.error('generic type name `${name}` is not mentioned in struct `${node.name}[${struct_generic_names}]`',
466 field.type_pos)
467 }
468 }
469 }
470 }
471 if node.generic_types.len == 0 && has_generic_types {
472 c.error('generic struct `${node.name}` declaration must specify the generic type names, e.g. ${node.name}[T]',
473 node.pos)
474 }
475 }
476 // Handle `implements` if it's present
477 if node.is_implements {
478 // XTODO2
479 // cgen error if I use `println(sym)` without handling the option with `or{}`
480 struct_type := c.table.find_type(node.name) // or { panic(err) }
481 mut names_used := []string{}
482 for t in node.implements_types {
483 t_sym := c.table.sym(t.typ)
484 if t_sym.info is ast.Interface {
485 if t_sym.info.is_generic {
486 if t_sym.generic_types.len == 0 && !t.typ.has_flag(.generic) {
487 c.error('missing generic type on ${t_sym.name}', t.pos)
488 } else {
489 struct_generic_letters := node.generic_types.map(c.table.type_to_str(it))
490 unknown_letters :=
491 t_sym.generic_types.filter(it.has_flag(.generic)).map(c.table.type_to_str(it)).filter(it !in struct_generic_letters)
492 if unknown_letters.len > 0 {
493 c.error('unknown generic type ${unknown_letters.first()}', t.pos)
494 }
495 }
496 }
497 variant_name := c.table.type_to_str(t.typ)
498 if variant_name in names_used {
499 c.error('struct type ${node.name} cannot implement interface `${t_sym.name} more than once`',
500 t.pos)
501 }
502 names_used << variant_name
503 } else {
504 c.error('`${t_sym.name}` is not an interface type', t.pos)
505 }
506 c.type_implements(struct_type, t.typ, node.pos)
507 }
508 }
509}
510
511fn minify_sort_fn(a &ast.StructField, b &ast.StructField) int {
512 if a.typ == b.typ {
513 return 0
514 }
515 // push all bool fields to the end of the struct
516 if a.typ == ast.bool_type_idx {
517 if b.typ == ast.bool_type_idx {
518 return 0
519 }
520 return 1
521 } else if b.typ == ast.bool_type_idx {
522 return -1
523 }
524
525 mut t := global_table
526 a_sym := t.sym(a.typ)
527 b_sym := t.sym(b.typ)
528
529 // push all non-flag enums to the end too, just before the bool fields
530 // TODO: support enums with custom field values as well
531 if a_sym.info is ast.Enum {
532 if !a_sym.info.is_flag && !a_sym.info.uses_exprs {
533 return if b_sym.info is ast.Enum {
534 match true {
535 a_sym.info.vals.len > b_sym.info.vals.len { -1 }
536 a_sym.info.vals.len < b_sym.info.vals.len { 1 }
537 else { 0 }
538 }
539 } else {
540 1
541 }
542 }
543 } else if b_sym.info is ast.Enum {
544 if !b_sym.info.is_flag && !b_sym.info.uses_exprs {
545 return -1
546 }
547 }
548
549 a_size, a_align := t.type_size(a.typ)
550 b_size, b_align := t.type_size(b.typ)
551 return match true {
552 a_align > b_align { -1 }
553 a_align < b_align { 1 }
554 a_size > b_size { -1 }
555 a_size < b_size { 1 }
556 else { 0 }
557 }
558}
559
560fn (mut c Checker) struct_init_selector_type_expr(mut expr ast.SelectorExpr) ast.Type {
561 if !is_array_init_type_expr_field(expr.field_name) {
562 return ast.void_type
563 }
564 base_type := c.struct_init_type_expr(mut expr.expr)
565 if base_type == ast.void_type {
566 return ast.void_type
567 }
568 return c.type_resolver.typeof_field_type(base_type, expr.field_name)
569}
570
571fn (mut c Checker) struct_init_type_expr(mut expr ast.Expr) ast.Type {
572 return match mut expr {
573 ast.TypeNode {
574 expr.typ
575 }
576 ast.ParExpr {
577 c.struct_init_type_expr(mut expr.expr)
578 }
579 ast.TypeOf {
580 if expr.is_type {
581 c.recheck_concrete_type(expr.typ)
582 } else {
583 if expr.typ == 0 || expr.typ == ast.void_type || expr.typ == ast.no_type {
584 expr.typ = c.expr(mut expr.expr)
585 }
586 resolved_type := c.recheck_concrete_type(expr.typ)
587 if resolved_type != 0 && resolved_type != ast.void_type
588 && resolved_type != ast.no_type {
589 resolved_type
590 } else {
591 c.recheck_concrete_type(c.type_resolver.typeof_type(expr.expr, expr.typ))
592 }
593 }
594 }
595 ast.Ident {
596 if c.is_generic_type_expr_ident(expr.name) {
597 c.table.find_type(expr.name).set_flag(.generic)
598 } else {
599 c.get_expr_type(expr)
600 }
601 }
602 ast.SelectorExpr {
603 c.struct_init_selector_type_expr(mut expr)
604 }
605 else {
606 ast.void_type
607 }
608 }
609}
610
611fn (c &Checker) struct_init_uses_comptime_type_accessor(expr ast.Expr) bool {
612 return match expr {
613 ast.ParExpr {
614 c.struct_init_uses_comptime_type_accessor(expr.expr)
615 }
616 ast.SelectorExpr {
617 mut is_base_type_expr := expr.expr is ast.TypeOf
618 || c.struct_init_uses_comptime_type_accessor(expr.expr)
619 if expr.expr is ast.Ident {
620 is_base_type_expr = is_base_type_expr
621 || c.is_generic_type_expr_ident(expr.expr.name)
622 }
623 expr.field_name in ['idx', 'typ', 'unaliased_typ', 'key_type', 'value_type', 'element_type', 'pointee_type', 'payload_type']
624 && is_base_type_expr
625 }
626 else {
627 false
628 }
629 }
630}
631
632fn (mut c Checker) struct_init(mut node ast.StructInit, is_field_zero_struct_init bool, mut inited_fields []string) ast.Type {
633 util.timing_start(@METHOD)
634 old_expected_type := c.expected_type
635 defer {
636 c.expected_type = old_expected_type
637 util.timing_measure_cumulative(@METHOD)
638 }
639 short_syntax_expected_type_sym := c.table.sym(c.unwrap_generic(c.expected_type))
640 short_syntax_infers_anon_from_generic_param := node.is_short_syntax && node.typ == ast.void_type
641 && c.expected_type != ast.void_type && c.expected_type.has_flag(.generic)
642 && short_syntax_expected_type_sym.kind == .any
643 && !short_syntax_expected_type_sym.is_builtin()
644 is_comptime_type_struct_init := !node.is_short_syntax && node.typ_expr !is ast.EmptyExpr
645 && c.struct_init_uses_comptime_type_accessor(node.typ_expr)
646 should_resolve_typ_expr := node.typ == ast.void_type
647 || (is_comptime_type_struct_init && c.has_active_generic_recheck_context())
648 if should_resolve_typ_expr && !node.is_short_syntax && node.typ_expr !is ast.EmptyExpr {
649 if !is_comptime_type_struct_init {
650 c.expr(mut node.typ_expr)
651 }
652 node.typ = c.struct_init_type_expr(mut node.typ_expr)
653 if node.typ == ast.void_type || node.typ == ast.no_type {
654 c.error('cannot use `${node.typ_expr}` as a struct init type', node.typ_expr.pos())
655 return ast.void_type
656 }
657 node.unresolved = !is_comptime_type_struct_init && node.typ.has_flag(.generic)
658 }
659 source_typ := if node.is_short_syntax && c.expected_type != ast.void_type
660 && !short_syntax_infers_anon_from_generic_param {
661 c.expected_type
662 } else if node.typ != ast.void_type {
663 node.typ
664 } else {
665 c.expected_type
666 }
667 mut source_generic_typ := source_typ
668 source_sym := c.table.sym(c.unwrap_generic(source_typ))
669 if source_sym.kind == .generic_inst && source_sym.info is ast.GenericInst {
670 source_generic_typ =
671 ast.new_type(source_sym.info.parent_idx).derive(source_typ).set_flag(.generic)
672 } else if source_sym.info is ast.Struct && source_sym.info.parent_type != 0
673 && source_sym.info.concrete_types.len > 0 {
674 source_generic_typ = source_sym.info.parent_type.derive(source_typ).set_flag(.generic)
675 }
676 if node.generic_typ == 0 && source_generic_typ != ast.void_type
677 && !short_syntax_infers_anon_from_generic_param && (source_generic_typ.has_flag(.generic)
678 || c.type_has_unresolved_generic_parts(source_generic_typ)) {
679 node.generic_typ = source_generic_typ
680 }
681 if c.has_active_generic_recheck_context() {
682 if !node.is_short_syntax && node.generic_typ != 0 {
683 // Only re-resolve if the node's current type still has unresolved generic parts.
684 // A concrete type like MultiLevel[int] should not be re-resolved when visited
685 // inside a different generic context (e.g., as a nested init in MultiLevel[MultiLevel[int]]).
686 if node.typ.has_flag(.generic) || node.typ == ast.void_type {
687 // Try resolving node.typ first — it may use the function's generic names
688 // (e.g., Item[A] where A is from the enclosing function), which are directly
689 // resolvable via cur_concrete_types. Only fall back to node.generic_typ
690 // (which uses the struct's own generic param names like T) if node.typ can't resolve.
691 resolved_typ := c.recheck_concrete_type(node.typ)
692 if resolved_typ != node.typ && resolved_typ != 0 && resolved_typ != ast.void_type
693 && !resolved_typ.has_flag(.generic) {
694 node.typ = resolved_typ
695 } else {
696 resolved_generic_typ := c.recheck_concrete_type(node.generic_typ)
697 if resolved_generic_typ != 0 && resolved_generic_typ != ast.void_type {
698 node.typ = resolved_generic_typ
699 }
700 }
701 }
702 }
703 }
704 if node.is_short_syntax && c.has_active_generic_recheck_context() {
705 node.typ = ast.void_type
706 }
707 if node.typ == ast.void_type {
708 // short syntax `foo(key:val, key2:val2)`
709 if c.expected_type == ast.void_type {
710 c.error('unexpected short struct syntax', node.pos)
711 return ast.void_type
712 }
713 if short_syntax_infers_anon_from_generic_param {
714 node.typ = ast.none_type
715 } else {
716 sym := c.table.sym(c.expected_type)
717 if sym.kind == .array {
718 node.typ = c.table.value_type(c.expected_type)
719 } else {
720 node.typ = c.expected_type
721 }
722 }
723 }
724 original_node_typ := node.typ
725 concrete_node_typ := c.recheck_concrete_type(node.typ)
726 $if trace_veb_guard ? {
727 if c.file.path.contains('/vlib/veb/veb.v') {
728 node_type_str := if node.typ == 0 { '<none>' } else { c.table.type_to_str(node.typ) }
729 concrete_type_str := if concrete_node_typ == 0 {
730 '<none>'
731 } else {
732 c.table.type_to_str(concrete_node_typ)
733 }
734 generic_type_str := if node.generic_typ == 0 {
735 '<none>'
736 } else {
737 c.table.type_to_str(node.generic_typ)
738 }
739 expected_type_str := if c.expected_type == 0 {
740 '<none>'
741 } else {
742 c.table.type_to_str(c.expected_type)
743 }
744 eprintln('struct_init typ=${node_type_str} concrete=${concrete_type_str} generic_typ=${generic_type_str} expected=${expected_type_str} short=${node.is_short_syntax} fields=${node.init_fields.map(it.name)}')
745 }
746 }
747 struct_sym := c.table.sym(concrete_node_typ)
748 mut old_inside_generic_struct_init := false
749 mut old_cur_struct_generic_types := []ast.Type{}
750 mut old_cur_struct_concrete_types := []ast.Type{}
751 if struct_sym.info is ast.Struct {
752 // check if the generic param types have been defined
753 for ct in struct_sym.info.concrete_types {
754 ct_sym := c.table.sym(ct)
755 if ct_sym.kind == .placeholder {
756 c.error('unknown type `${ct_sym.name}`', node.pos)
757 }
758 }
759 if struct_sym.info.generic_types.len > 0 && struct_sym.info.concrete_types.len == 0
760 && !node.is_short_syntax && c.table.cur_concrete_types.len != 0
761 && !is_field_zero_struct_init {
762 if node.generic_types.len == 0 {
763 c.error('generic struct init must specify type parameter, e.g. Foo[T]', node.pos)
764 } else if node.generic_types.len > 0
765 && node.generic_types.len != struct_sym.info.generic_types.len {
766 c.error('generic struct init expects ${struct_sym.info.generic_types.len} generic parameter, but got ${node.generic_types.len}',
767 node.pos)
768 } else if node.generic_types.len > 0 && c.table.cur_fn != unsafe { nil } {
769 for gtyp in node.generic_types {
770 if !gtyp.has_flag(.generic) {
771 continue
772 }
773 gtyp_name := c.table.sym(gtyp).name
774 if gtyp_name.len == 1 && gtyp_name !in c.table.cur_fn.generic_names {
775 cur_generic_names := '(' + c.table.cur_fn.generic_names.join(',') + ')'
776 c.error('generic struct init type parameter `${gtyp_name}` must be within the parameters `${cur_generic_names}` of the current generic function',
777 node.pos)
778 break
779 }
780 }
781 }
782 }
783 if node.generic_types.len > 0 && struct_sym.info.generic_types.len == 0 {
784 c.error('a non generic struct `${node.typ_str}` used like a generic struct',
785 node.name_pos)
786 }
787 if struct_sym.info.generic_types.len > 0
788 && struct_sym.info.generic_types.len == struct_sym.info.concrete_types.len {
789 old_inside_generic_struct_init = c.inside_generic_struct_init
790 old_cur_struct_generic_types = c.cur_struct_generic_types.clone()
791 old_cur_struct_concrete_types = c.cur_struct_concrete_types.clone()
792 c.inside_generic_struct_init = true
793 c.cur_struct_generic_types = struct_sym.info.generic_types.clone()
794 c.cur_struct_concrete_types = struct_sym.info.concrete_types.clone()
795 defer(fn) {
796 c.inside_generic_struct_init = old_inside_generic_struct_init
797 c.cur_struct_generic_types = old_cur_struct_generic_types
798 c.cur_struct_concrete_types = old_cur_struct_concrete_types
799 }
800 }
801 if struct_sym.info.is_union && node.init_fields.len > 1 {
802 c.error('union `${struct_sym.name}` can have only one field initialised', node.pos)
803 }
804 } else if struct_sym.info is ast.GenericInst {
805 // For generic_inst types (concrete generic structs like Seq[int]),
806 // set up the generic struct init context using the parent's generic types
807 // and the inst's concrete types.
808 parent_sym := c.table.sym(ast.new_type(struct_sym.info.parent_idx))
809 if parent_sym.info is ast.Struct {
810 if parent_sym.info.generic_types.len > 0
811 && parent_sym.info.generic_types.len == struct_sym.info.concrete_types.len {
812 old_inside_generic_struct_init = c.inside_generic_struct_init
813 old_cur_struct_generic_types = c.cur_struct_generic_types.clone()
814 old_cur_struct_concrete_types = c.cur_struct_concrete_types.clone()
815 c.inside_generic_struct_init = true
816 c.cur_struct_generic_types = parent_sym.info.generic_types.clone()
817 c.cur_struct_concrete_types = struct_sym.info.concrete_types.clone()
818 defer(fn) {
819 c.inside_generic_struct_init = old_inside_generic_struct_init
820 c.cur_struct_generic_types = old_cur_struct_generic_types
821 c.cur_struct_concrete_types = old_cur_struct_concrete_types
822 }
823 }
824 }
825 } else if struct_sym.info is ast.FnType {
826 c.error('functions must be defined, not instantiated like structs', node.pos)
827 }
828 // register generic struct type when current fn is generic fn
829 if c.table.cur_fn != unsafe { nil } && c.table.cur_fn.generic_names.len > 0 {
830 c.table.unwrap_generic_type_ex(node.typ, c.table.cur_fn.generic_names,
831 c.table.cur_concrete_types, true)
832 if c.pref.skip_unused && node.typ.has_flag(.generic) {
833 c.table.used_features.comptime_syms[c.unwrap_generic(node.typ)] = true
834 c.table.used_features.comptime_syms[node.typ] = true
835 }
836 }
837 type_sym := c.table.sym(concrete_node_typ)
838 is_generic_zero_struct_init := original_node_typ.has_flag(.generic) && node.init_fields.len == 0
839 && !node.has_update_expr
840 is_comptime_type_zero_struct_init := node.init_fields.len == 0 && !node.has_update_expr
841 && is_comptime_type_struct_init
842 if is_generic_zero_struct_init {
843 // Don't early-return for single-letter types (like F{}) in non-generic functions —
844 // these are unknown structs that should be caught by ensure_type_exists below.
845 is_unknown_single_letter := type_sym.kind == .any && type_sym.name.len == 1
846 && (c.table.cur_fn == unsafe { nil } || type_sym.name !in c.table.cur_fn.generic_names)
847 if !is_unknown_single_letter {
848 return concrete_node_typ
849 }
850 }
851 if !is_field_zero_struct_init && !is_comptime_type_zero_struct_init {
852 type_exists := c.ensure_type_exists(node.typ, node.pos)
853 if !type_exists && node.typ.idx() > 0 && c.table.sym(node.typ).kind == .placeholder {
854 return ast.void_type
855 }
856 }
857 if c.anon_struct_should_be_mut {
858 mut anon_type_sym := c.table.sym(node.typ)
859 if anon_type_sym.kind == .struct {
860 mut anon_info := anon_type_sym.info as ast.Struct
861 if anon_info.is_anon {
862 mut anon_fields := []ast.StructField{cap: anon_info.fields.len}
863 for field in anon_info.fields {
864 anon_fields << ast.StructField{
865 ...field
866 is_mut: true
867 }
868 }
869 anon_info.fields = anon_fields
870 anon_type_sym.info = anon_info
871 }
872 }
873 }
874 // Make sure the first letter is capital, do not allow e.g. `x := string{}`,
875 // but `x := T{}` is ok.
876 if !c.is_builtin_mod && !c.inside_unsafe && type_sym.language == .v
877 && c.table.cur_concrete_types.len == 0 {
878 pos := type_sym.name.last_index_u8(`.`)
879 first_letter := type_sym.name[pos + 1]
880 if !first_letter.is_capital() && type_sym.kind != .none
881 && (type_sym.kind != .struct || !(type_sym.info is ast.Struct && type_sym.info.is_anon))
882 && type_sym.kind != .placeholder {
883 c.error('cannot initialize builtin type `${type_sym.name}`', node.pos)
884 }
885 if type_sym.kind == .enum && !c.pref.translated && !c.file.is_translated {
886 c.error('cannot initialize enums', node.pos)
887 }
888 }
889 if type_sym.kind == .sum_type && node.init_fields.len == 1 {
890 sexpr := node.init_fields[0].expr.str()
891 c.error('cast to sum type using `${type_sym.name}(${sexpr})` not `${type_sym.name}{${sexpr}}`',
892 node.pos)
893 }
894 if type_sym.kind == .interface && type_sym.language != .js {
895 c.error('cannot instantiate interface `${type_sym.name}`', node.pos)
896 }
897 // allow init structs from generic if they're private except the type is from builtin module
898 is_generic_init := concrete_node_typ.has_flag(.generic)
899 || (node.generic_typ != 0 && node.generic_typ.has_flag(.generic))
900 if !node.has_update_expr && !type_sym.is_pub && type_sym.kind != .placeholder
901 && type_sym.language != .c
902 && (type_sym.mod != c.mod && !(is_generic_init && type_sym.mod != 'builtin'))
903 && !is_field_zero_struct_init && !is_comptime_type_zero_struct_init {
904 c.error('type `${type_sym.name}` is private', node.pos)
905 }
906 if type_sym.info is ast.Struct && type_sym.mod != c.mod && !is_field_zero_struct_init {
907 for attr in type_sym.info.attrs {
908 match attr.name {
909 'noinit' {
910 c.error(
911 'struct `${type_sym.name}` is declared with a `@[noinit]` attribute, so ' +
912 'it cannot be initialized with `${type_sym.name}{}`', node.pos)
913 }
914 'deprecated' {
915 c.deprecate('struct', type_sym.name, type_sym.info.attrs, node.pos)
916 }
917 else {}
918 }
919 }
920 }
921 if type_sym.name.len == 1 && c.table.cur_fn != unsafe { nil }
922 && c.table.cur_fn.generic_names.len == 0 {
923 c.error('unknown struct `${type_sym.name}`', node.pos)
924 return ast.void_type
925 }
926 match type_sym.kind {
927 .placeholder {
928 c.error('unknown struct: ${type_sym.name}', node.pos)
929 return ast.void_type
930 }
931 .any {
932 // `T{ foo: 22 }`
933 for mut init_field in node.init_fields {
934 init_field.typ = c.expr(mut init_field.expr)
935 init_field.expected_type = init_field.typ
936 }
937 sym := c.table.sym(c.unwrap_generic(node.typ))
938 if sym.info is ast.Struct {
939 if sym.mod != c.mod {
940 for attr in sym.info.attrs {
941 match attr.name {
942 'noinit' {
943 c.error(
944 'struct `${sym.name}` is declared with a `@[noinit]` attribute, so ' +
945 'it cannot be initialized with `${sym.name}{}`', node.pos)
946 }
947 'deprecated' {
948 c.deprecate('struct', sym.name, sym.info.attrs, node.pos)
949 }
950 else {}
951 }
952 }
953 }
954 if node.no_keys && node.init_fields.len != sym.info.fields.len {
955 fname := if sym.info.fields.len != 1 { 'fields' } else { 'field' }
956 c.error('initializing struct `${sym.name}` needs `${sym.info.fields.len}` ${fname}, but got `${node.init_fields.len}`',
957 node.pos)
958 }
959 }
960 }
961 // string & array are also structs but .kind of string/array
962 .struct, .string, .array, .alias, .generic_inst {
963 mut info := ast.Struct{}
964 if type_sym.kind == .alias {
965 info_t := type_sym.info as ast.Alias
966 sym := c.table.final_sym(info_t.parent_type)
967 if sym.kind == .placeholder { // pending import symbol did not resolve
968 c.error('unknown struct: ${type_sym.name}', node.pos)
969 return ast.void_type
970 }
971 match sym.kind {
972 .struct {
973 info = sym.info as ast.Struct
974 }
975 .array, .array_fixed, .map {
976 // we do allow []int{}, [10]int{}, map[string]int{}
977 }
978 .sum_type, .interface {
979 // allow alias-of-sumtype/interface init (e.g. SumAlias{})
980 }
981 else {
982 if !((sym.is_number() || sym.kind == .string
983 || sym.kind == .bool || sym.kind == .enum) && node.init_fields.len == 0
984 && !node.has_update_expr) && !c.has_active_generic_recheck_context() {
985 c.error('alias type name: ${sym.name} is not struct type', node.pos)
986 }
987 }
988 }
989 } else if type_sym.kind == .generic_inst && type_sym.info is ast.GenericInst {
990 parent_sym := c.table.sym(ast.new_type(type_sym.info.parent_idx))
991 if parent_sym.info is ast.Struct {
992 info = parent_sym.info
993 }
994 } else {
995 info = type_sym.info as ast.Struct
996 }
997 if node.no_keys {
998 exp_len := info.fields.len
999 got_len := node.init_fields.len
1000 if exp_len != got_len && !c.pref.translated {
1001 // XTODO remove !translated check
1002 amount := if exp_len < got_len { 'many' } else { 'few' }
1003 c.error('too ${amount} fields in `${type_sym.name}` literal (expecting ${exp_len}, got ${got_len})',
1004 node.pos)
1005 }
1006 }
1007 mut info_fields_sorted := []ast.StructField{}
1008 if node.no_keys {
1009 info_fields_sorted = info.fields.clone()
1010 info_fields_sorted.sort(a.i < b.i)
1011 }
1012 for i, mut init_field in node.init_fields {
1013 mut field_info := ast.StructField{}
1014 mut field_name := ''
1015 if node.no_keys {
1016 if i >= info.fields.len {
1017 // It doesn't make sense to check for fields that don't exist.
1018 // We should just stop here.
1019 break
1020 }
1021 field_info = info_fields_sorted[i]
1022 field_name = field_info.name
1023 node.init_fields[i].name = field_name
1024 } else {
1025 field_name = init_field.name
1026 mut exists := true
1027 field_info = c.table.find_field_with_embeds(type_sym, field_name) or {
1028 exists = false
1029 ast.StructField{}
1030 }
1031 if !exists {
1032 existing_fields := c.table.struct_fields(type_sym).map(it.name)
1033 c.error(util.new_suggestion(init_field.name, existing_fields).say('unknown field `${init_field.name}` in struct literal of type `${type_sym.name}`'),
1034 init_field.pos)
1035 continue
1036 }
1037 if field_name in inited_fields {
1038 c.error('duplicate field name in struct literal: `${field_name}`',
1039 init_field.pos)
1040 continue
1041 }
1042 }
1043 mut got_type := ast.no_type
1044 mut exp_type := ast.no_type
1045 inited_fields << field_name
1046 exp_type = field_info.typ
1047 if c.inside_generic_struct_init && exp_type.has_flag(.generic) {
1048 generic_names := c.cur_struct_generic_types.map(c.table.sym(it).name)
1049 if unwrapped := c.table.convert_generic_type(exp_type, generic_names,
1050 c.cur_struct_concrete_types)
1051 {
1052 exp_type = unwrapped
1053 }
1054 }
1055 exp_type = c.recheck_concrete_type(exp_type)
1056 exp_type_sym := c.table.sym(exp_type)
1057 exp_final_sym := if exp_type_sym.kind == .generic_inst {
1058 c.table.sym(ast.new_type((exp_type_sym.info as ast.GenericInst).parent_idx))
1059 } else {
1060 exp_type_sym
1061 }
1062 c.expected_type = exp_type
1063 nr_errors_before := c.nr_errors
1064 got_type = c.expr(mut init_field.expr)
1065 got_type_sym := c.table.sym(got_type)
1066 if got_type == ast.void_type && c.nr_errors == nr_errors_before {
1067 c.error('`${init_field.expr}` (no value) used as value', init_field.pos)
1068 }
1069 exp_type_is_option := exp_type.has_flag(.option)
1070 if !exp_type_is_option {
1071 got_type = c.check_expr_option_or_result_call(init_field.expr, got_type)
1072 init_field.typ = got_type
1073 has_or_block := match mut init_field.expr {
1074 ast.IndexExpr { init_field.expr.or_expr.kind != .absent }
1075 ast.CallExpr { init_field.expr.or_block.kind != .absent }
1076 ast.SelectorExpr { init_field.expr.or_block.kind != .absent }
1077 else { false }
1078 }
1079
1080 if got_type.has_flag(.option) && !has_or_block {
1081 c.error('cannot assign an Option value to a non-option struct field',
1082 init_field.pos)
1083 } else if got_type.has_flag(.result) && !has_or_block {
1084 c.error('cannot assign a Result value to a non-option struct field',
1085 init_field.pos)
1086 }
1087 }
1088 if got_type.has_flag(.result) {
1089 c.check_expr_option_or_result_call(init_field.expr, init_field.typ)
1090 }
1091 if exp_type_is_option && got_type.is_ptr() && !exp_type.is_ptr() {
1092 c.error('cannot assign a pointer to option struct field', init_field.pos)
1093 }
1094 c.warn_if_integer_literal_overflow_for_known_type(exp_type, init_field.expr,
1095 init_field.pos)
1096 if exp_type_sym.kind == .voidptr {
1097 if got_type_sym.kind == .struct && !got_type.is_ptr() {
1098 c.error('allocate `${got_type_sym.name}` on the heap for use in other functions',
1099 init_field.pos)
1100 } else if got_type !in [ast.nil_type, ast.voidptr_type, ast.byteptr_type]
1101 && !got_type.is_ptr() && (init_field.expr !is ast.IntegerLiteral
1102 || (init_field.expr is ast.IntegerLiteral
1103 && init_field.expr.val.int() != 0)) {
1104 c.note('voidptr variables may only be assigned voidptr values (e.g. unsafe { voidptr(${init_field.expr.str()}) })',
1105 init_field.expr.pos())
1106 }
1107 }
1108 // disallow `mut a: b`, when b is const map
1109 if exp_type_sym.kind == .map && got_type_sym.kind == .map && !got_type.is_ptr()
1110 && field_info.is_mut
1111 && (init_field.expr is ast.Ident && init_field.expr.obj is ast.ConstField) {
1112 c.error('cannot assign a const map to mut struct field, call `clone` method (or use a reference)',
1113 init_field.expr.pos())
1114 }
1115 if c.is_nocopy_struct(exp_type) && c.is_nocopy_struct(got_type)
1116 && init_field.expr !is ast.StructInit {
1117 c.error('cannot copy @[nocopy] struct: use a reference instead',
1118 init_field.expr.pos())
1119 }
1120 if exp_type_sym.kind == .array && got_type_sym.kind == .array {
1121 init_field_expr_pos := init_field.expr.pos()
1122 if init_field.expr is ast.IndexExpr && init_field.expr.left is ast.Ident
1123 && ((init_field.expr as ast.IndexExpr).left.is_mut()
1124 || field_info.is_mut) && init_field.expr.index is ast.RangeExpr
1125 && !c.inside_unsafe {
1126 // `a: arr[..]` auto add clone() -> `a: arr[..].clone()`
1127 c.add_error_detail_with_pos('To silence this notice, use either an explicit `a[..].clone()`,
1128or use an explicit `unsafe{ a[..] }`, if you do not want a copy of the slice.',
1129 init_field_expr_pos)
1130 c.note('an implicit clone of the slice was done here', init_field_expr_pos)
1131 mut right := ast.CallExpr{
1132 name: 'clone'
1133 kind: .clone
1134 left: init_field.expr
1135 left_type: got_type
1136 is_method: true
1137 receiver_type: got_type.ref()
1138 return_type: got_type
1139 scope: c.fn_scope
1140 is_return_used: true
1141 }
1142 got_type = c.expr(mut right)
1143 node.init_fields[i].expr = right
1144 }
1145 // disallow `mut a: b`, when b is const array
1146 if field_info.is_mut
1147 && (init_field.expr is ast.Ident && init_field.expr.obj is ast.ConstField)
1148 && !c.inside_unsafe {
1149 c.error('cannot assign a const array to mut struct field, call `clone` method (or use `unsafe`)',
1150 init_field.expr.pos())
1151 }
1152 }
1153 if exp_final_sym.kind == .interface {
1154 if c.type_implements(got_type, exp_type, init_field.pos) {
1155 if !c.inside_unsafe && got_type_sym.kind != .interface
1156 && !got_type.is_any_kind_of_pointer() {
1157 c.mark_as_referenced(mut &init_field.expr, true)
1158 }
1159 }
1160 } else if got_type != ast.void_type && got_type_sym.kind != .placeholder
1161 && !exp_type.has_flag(.generic) {
1162 mut needs_sum_type_cast := false
1163 if exp_type_sym.kind == .placeholder {
1164 base_type := c.table.find_type(exp_type_sym.ngname)
1165 if base_type != 0 {
1166 base_sym := c.table.sym(base_type)
1167 if base_sym.kind == .sum_type && base_sym.info is ast.SumType {
1168 base_info := base_sym.info as ast.SumType
1169 for variant in base_info.variants {
1170 if c.table.sym(variant).ngname == got_type_sym.ngname {
1171 needs_sum_type_cast = true
1172 break
1173 }
1174 }
1175 }
1176 }
1177 }
1178 if needs_sum_type_cast {
1179 init_field.expr = ast.CastExpr{
1180 expr: init_field.expr
1181 typ: exp_type
1182 typname: c.table.type_to_str(exp_type)
1183 pos: init_field.expr.pos()
1184 }
1185 init_field.typ = exp_type
1186 } else if c.has_direct_numeric_alias_struct_init_mismatch(init_field.expr,
1187 got_type, exp_type)
1188 {
1189 c.error('cannot assign to field `${field_info.name}`: ${c.expected_msg(got_type,
1190 exp_type)}', init_field.pos)
1191 } else {
1192 c.check_expected(c.unwrap_generic(got_type), c.unwrap_generic(exp_type)) or {
1193 // For generic types, the same concrete type may have been
1194 // registered with different indices through different code
1195 // paths. Compare by type string as a fallback.
1196 got_unwrapped := c.unwrap_generic(got_type)
1197 exp_unwrapped := c.unwrap_generic(exp_type)
1198 if c.table.type_to_str(got_unwrapped) == c.table.type_to_str(exp_unwrapped) {
1199 // Same concrete type by name, different index - accept
1200 } else if field_info.typ.has_flag(.generic)
1201 || exp_type != field_info.typ {
1202 c.error('cannot assign `${c.table.type_to_str(got_unwrapped)}` to struct field `${field_info.name}` with type `${c.table.type_to_str(exp_unwrapped)}`',
1203 init_field.expr.pos())
1204 } else {
1205 c.error('cannot assign to field `${field_info.name}`: ${err.msg()}',
1206 init_field.pos)
1207 }
1208 }
1209 }
1210 }
1211 if exp_type.has_flag(.shared_f) {
1212 if !got_type.has_flag(.shared_f) && got_type.is_ptr() {
1213 c.error('`shared` field must be initialized with `shared` or value',
1214 init_field.pos)
1215 }
1216 } else {
1217 if !c.inside_unsafe && type_sym.language == .v && !(c.file.is_translated
1218 || c.pref.translated) && exp_type.is_ptr()
1219 && !got_type.is_any_kind_of_pointer() && !exp_type_is_option
1220 && !(init_field.expr is ast.UnsafeExpr && init_field.expr.expr.str() == '0') {
1221 if init_field.expr.str() == '0' {
1222 c.error('assigning `0` to a reference field is only allowed in `unsafe` blocks',
1223 init_field.pos)
1224 } else {
1225 c.error('reference field must be initialized with reference',
1226 init_field.pos)
1227 }
1228 } else if exp_type.is_any_kind_of_pointer()
1229 && !got_type.is_any_kind_of_pointer() && !got_type.is_int()
1230 && (!exp_type_is_option || got_type.idx() != ast.none_type_idx) {
1231 got_typ_str := c.table.type_to_str(got_type)
1232 exp_typ_str := c.table.type_to_str(exp_type)
1233 c.error('cannot assign to field `${field_info.name}`: expected a pointer `${exp_typ_str}`, but got `${got_typ_str}`',
1234 init_field.pos)
1235 }
1236 }
1237 node.init_fields[i].typ = got_type
1238 node.init_fields[i].expected_type = exp_type
1239
1240 if got_type.is_ptr() && exp_type.is_ptr() && mut init_field.expr is ast.Ident
1241 && !info.is_heap {
1242 c.fail_if_stack_struct_action_outside_unsafe(mut init_field.expr, 'assigned')
1243 }
1244 if c.table.unaliased_type(exp_type) in ast.unsigned_integer_type_idxs
1245 && mut init_field.expr is ast.IntegerLiteral
1246 && (init_field.expr as ast.IntegerLiteral).val[0] == `-` {
1247 c.error('cannot assign negative value to unsigned integer type',
1248 init_field.expr.pos)
1249 }
1250
1251 if exp_type_sym.info is ast.Struct && !exp_type_sym.info.is_anon
1252 && mut init_field.expr is ast.StructInit && init_field.expr.is_anon {
1253 c.error('cannot assign anonymous `struct` to a typed `struct`',
1254 init_field.expr.pos)
1255 }
1256
1257 // all the fields of initialized embedded struct are ignored, they are considered initialized
1258 sym := c.table.sym(init_field.typ)
1259 if init_field.is_embed && sym.kind == .struct && sym.language == .v {
1260 struct_fields := c.table.struct_fields(sym)
1261 for struct_field in struct_fields {
1262 inited_fields << struct_field.name
1263 }
1264 }
1265 expected_type_sym := c.table.final_sym(init_field.expected_type)
1266 if expected_type_sym.kind in [.string, .array, .map, .array_fixed, .chan, .struct]
1267 && init_field.expr.is_nil() && !init_field.expected_type.is_ptr()
1268 && mut init_field.expr is ast.UnsafeExpr {
1269 c.error('cannot assign `nil` to struct field `${init_field.name}` with type `${expected_type_sym.name}`',
1270 init_field.expr.pos.extend(init_field.expr.expr.pos()))
1271 }
1272 if mut init_field.expr is ast.CallExpr
1273 && init_field.expr.return_type.has_flag(.generic) {
1274 expected_type := c.unwrap_generic(init_field.expected_type)
1275 mut got_type_ret := c.unwrap_generic(init_field.expr.return_type)
1276 if init_field.expr.or_block.kind != .absent {
1277 got_type_ret = got_type_ret.clear_option_and_result()
1278 }
1279 if expected_type != got_type_ret {
1280 c.error('cannot assign `${c.table.type_to_str(got_type_ret)}` to struct field `${init_field.name}` with type `${c.table.type_to_str(expected_type)}`',
1281 init_field.expr.pos)
1282 }
1283 }
1284 }
1285 if !node.has_update_expr {
1286 c.check_uninitialized_struct_fields_and_embeds(node, type_sym, mut info, mut
1287 inited_fields)
1288 }
1289 // println('>> checked_types.len: ${checked_types.len} | checked_types: ${checked_types} | type_sym: ${type_sym.name} ')
1290 }
1291 .sum_type {
1292 first_typ := (type_sym.info as ast.SumType).variants[0]
1293 first_sym := c.table.final_sym(first_typ)
1294 if first_sym.kind == .struct {
1295 mut info := first_sym.info as ast.Struct
1296 c.check_uninitialized_struct_fields_and_embeds(node, first_sym, mut info, mut
1297 inited_fields)
1298 }
1299 }
1300 .none {
1301 // var := struct { name: "" }
1302 mut init_fields := []ast.StructField{}
1303 for mut init_field in node.init_fields {
1304 mut expr := unsafe { init_field }
1305 init_field.typ = ast.mktyp(c.expr(mut expr.expr))
1306 init_field.expected_type = init_field.typ
1307 init_fields << ast.StructField{
1308 name: init_field.name
1309 typ: init_field.typ
1310 is_mut: c.anon_struct_should_be_mut
1311 }
1312 }
1313 c.table.anon_struct_counter++
1314 name := '_VAnonStruct${c.table.anon_struct_counter}'
1315 sym_struct := ast.TypeSymbol{
1316 kind: .struct
1317 language: .v
1318 name: name
1319 cname: util.no_dots(name)
1320 mod: c.mod
1321 info: ast.Struct{
1322 is_anon: true
1323 fields: init_fields
1324 }
1325 is_pub: true
1326 }
1327 ret := c.table.register_sym(sym_struct)
1328 c.table.register_anon_struct(name, ret)
1329 node = ast.StructInit{
1330 ...node
1331 typ: c.table.find_type_idx(name)
1332 typ_str: name
1333 is_anon: true
1334 is_short_syntax: false
1335 }
1336 }
1337 else {}
1338 }
1339
1340 if node.has_update_expr {
1341 update_type := c.recheck_concrete_type(c.expr(mut node.update_expr))
1342 node.update_expr_type = update_type
1343 expr_sym := c.table.final_sym(c.unwrap_generic(update_type))
1344 if node.update_expr is ast.ComptimeSelector {
1345 c.error('cannot use struct update syntax in compile time expressions',
1346 node.update_expr_pos)
1347 } else if expr_sym.kind != .struct {
1348 s := c.table.type_to_str(update_type)
1349 c.error('expected struct, found `${s}`', node.update_expr.pos())
1350 } else if update_type != concrete_node_typ {
1351 from_sym := c.table.final_sym(update_type)
1352 to_sym := c.table.final_sym(concrete_node_typ)
1353 from_info := from_sym.info as ast.Struct
1354 to_info := to_sym.info as ast.Struct
1355 // TODO: this check is too strict
1356 if !c.check_struct_signature(from_info, to_info)
1357 || !c.check_struct_signature_init_fields(from_info, to_info, node) {
1358 c.error('struct `${from_sym.name}` is not compatible with struct `${to_sym.name}`',
1359 node.update_expr.pos())
1360 }
1361 }
1362 }
1363 if struct_sym.info is ast.Struct && struct_sym.info.generic_types.len > 0
1364 && c.table.cur_concrete_types.len == 0 {
1365 if struct_sym.info.concrete_types.len == 0 {
1366 concrete_types := c.infer_struct_generic_types(node.typ, node)
1367 if concrete_types.len > 0 {
1368 idx := c.table.find_or_register_generic_inst(node.typ, concrete_types)
1369 if idx > 0 {
1370 node.typ = ast.new_type(idx)
1371 c.table.generic_insts_to_concrete()
1372 }
1373 }
1374 } else if struct_sym.info.generic_types.len == struct_sym.info.concrete_types.len {
1375 parent_type := struct_sym.info.parent_type
1376 parent_sym := c.table.sym(parent_type)
1377 if c.inside_generic_struct_init {
1378 mut st := unsafe { struct_sym.info }
1379 for mut field in st.fields {
1380 sym := c.table.sym(field.typ)
1381 if sym.info is ast.ArrayFixed && c.array_fixed_has_unresolved_size(sym.info) {
1382 mut size_expr := unsafe { sym.info.size_expr }
1383 field.typ = c.eval_array_fixed_sizes(mut size_expr, 0, sym.info.elem_type)
1384 }
1385 }
1386 }
1387 for method in parent_sym.methods {
1388 generic_names := struct_sym.info.generic_types.map(c.table.sym(it).name)
1389 for i, param in method.params {
1390 if i == 0 || !param.typ.has_flag(.generic) {
1391 continue
1392 }
1393 param_sym := c.table.sym(param.typ)
1394 if param_sym.kind in [.struct, .interface, .sum_type] {
1395 c.table.unwrap_generic_type(param.typ, generic_names,
1396 struct_sym.info.concrete_types)
1397 }
1398 }
1399 }
1400 }
1401 }
1402 return node.typ
1403}
1404
1405fn (c &Checker) has_direct_numeric_alias_struct_init_mismatch(expr ast.Expr, got ast.Type, expected ast.Type) bool {
1406 if expr.remove_par() !is ast.Ident && expr.remove_par() !is ast.SelectorExpr {
1407 return false
1408 }
1409 got_sym := c.table.sym(got)
1410 if got_sym.kind != .alias || got_sym.info !is ast.Alias {
1411 return false
1412 }
1413 got_num_type := c.table.unalias_num_type(got).clear_flags()
1414 expected_num_type := c.table.unalias_num_type(expected).clear_flags()
1415 if !got_num_type.is_number() || !expected_num_type.is_number() {
1416 return false
1417 }
1418 return c.promote_num(expected_num_type, got_num_type) != expected_num_type
1419}
1420
1421// Check uninitialized refs/sum types
1422// The variable `fields` contains two parts, the first part is the same as info.fields,
1423// and the second part is all fields embedded in the structure
1424// If the return value data composition form in `c.table.struct_fields()` is modified,
1425// need to modify here accordingly.
1426fn (mut c Checker) check_uninitialized_struct_fields_and_embeds(node ast.StructInit, type_sym ast.TypeSymbol, mut info ast.Struct, mut inited_fields []string) {
1427 mut fields := c.table.struct_fields(type_sym)
1428 mut checked_types := []ast.Type{}
1429 for i, mut field in fields {
1430 if field.name in inited_fields {
1431 if c.mod != type_sym.mod {
1432 if !field.is_pub {
1433 parts := type_sym.name.split('.')
1434 for init_field in node.init_fields {
1435 if field.name == init_field.name {
1436 mod_type := if parts.len > 1 {
1437 parts#[-2..].join('.')
1438 } else {
1439 parts.last()
1440 }
1441 if !c.inside_unsafe && !(c.is_js_backend
1442 && mod_type.starts_with('Promise')) {
1443 c.error('cannot access private field `${field.name}` on `${mod_type}`',
1444 init_field.pos)
1445
1446 break
1447 }
1448 }
1449 }
1450 }
1451 if field.is_deprecated {
1452 for init_field in node.init_fields {
1453 if field.name == init_field.name {
1454 c.deprecate('field', field.name, field.attrs, init_field.pos)
1455 break
1456 }
1457 }
1458 }
1459 }
1460 continue
1461 }
1462 sym := c.table.sym(field.typ)
1463 if field.is_embed && sym.info is ast.Struct {
1464 // struct embeds
1465 continue
1466 }
1467 if field.has_default_expr {
1468 if i < info.fields.len && field.default_expr_typ == 0 {
1469 if mut field.default_expr is ast.StructInit {
1470 idx := c.table.find_type(field.default_expr.typ_str)
1471 if idx != 0 {
1472 info.fields[i].default_expr_typ = ast.new_type(int(idx))
1473 }
1474 } else if field.default_expr.is_nil() {
1475 if field.typ.is_any_kind_of_pointer() {
1476 info.fields[i].default_expr_typ = field.typ
1477 }
1478 } else {
1479 is_ident_fn_default := field.default_expr is ast.Ident
1480 && field.default_expr.info is ast.IdentFn
1481 if is_ident_fn_default {
1482 mut default_expr := field.default_expr
1483 c.expr(mut default_expr)
1484 field.default_expr = default_expr
1485 } else if const_field := c.table.global_scope.find_const('${field.default_expr}') {
1486 info.fields[i].default_expr_typ = const_field.typ
1487 } else if type_sym.info is ast.Struct && type_sym.info.is_anon {
1488 c.expected_type = field.typ
1489 field.default_expr_typ = c.expr(mut field.default_expr)
1490 info.fields[i].default_expr_typ = field.default_expr_typ
1491 }
1492 }
1493 }
1494 continue
1495 }
1496 field_is_option := field.typ.has_flag(.option)
1497 if field.typ.is_ptr() && !field.typ.has_flag(.shared_f) && !field_is_option
1498 && !node.has_update_expr && !c.pref.translated && !c.file.is_translated {
1499 // Skip this check during generic recheck (concrete instantiation),
1500 // because generic code like `T{}` or `Struct[V]{}` cannot provide
1501 // initializers for reference fields that only appear after type substitution.
1502 if !c.has_active_generic_recheck_context() {
1503 c.error('reference field `${type_sym.name}.${field.name}` must be initialized',
1504 node.pos)
1505 continue
1506 }
1507 }
1508 if !field_is_option && !c.has_active_generic_recheck_context() {
1509 if sym.kind == .struct {
1510 c.check_ref_fields_initialized(sym, mut checked_types,
1511 '${type_sym.name}.${field.name}', node.pos)
1512 } else if sym.kind == .alias {
1513 parent_sym := c.table.sym((sym.info as ast.Alias).parent_type)
1514 if parent_sym.kind == .struct {
1515 c.check_ref_fields_initialized(parent_sym, mut checked_types,
1516 '${type_sym.name}.${field.name}', node.pos)
1517 }
1518 }
1519 }
1520 // Do not allow empty uninitialized interfaces
1521 if sym.kind == .interface && !node.has_update_expr && !field_is_option
1522 && sym.language != .js && !field.attrs.contains('noinit') {
1523 // TODO: should be an error instead, but first `ui` needs updating.
1524 c.note('interface field `${type_sym.name}.${field.name}` must be initialized', node.pos)
1525 }
1526 // Do not allow empty uninitialized sum types
1527 /*
1528 sym := c.table.sym(field.typ)
1529 if sym.kind == .sum_type {
1530 c.warn('sum type field `${type_sym.name}.${field.name}` must be initialized',
1531 node.pos)
1532 }
1533 */
1534 // Check for `@[required]` struct attr
1535 if !node.no_keys && !node.has_update_expr && field.attrs.contains('required')
1536 && node.init_fields.all(it.name != field.name)
1537 && !c.has_active_generic_recheck_context() {
1538 c.error('field `${type_sym.name}.${field.name}` must be initialized', node.pos)
1539 }
1540 if !node.has_update_expr && !field.has_default_expr && !field.typ.is_ptr()
1541 && !field_is_option {
1542 field_final_sym := c.table.final_sym(field.typ)
1543 if field_final_sym.kind == .struct {
1544 mut zero_struct_init := ast.StructInit{
1545 pos: node.pos
1546 typ: field.typ
1547 }
1548 if field.is_part_of_union {
1549 if field.name in inited_fields {
1550 // fields that are part of an union, should only be checked, when they are explicitly initialised
1551 c.struct_init(mut zero_struct_init, true, mut inited_fields)
1552 }
1553 } else {
1554 c.struct_init(mut zero_struct_init, true, mut inited_fields)
1555 }
1556 }
1557 }
1558 }
1559
1560 for embed in info.embeds {
1561 embed_sym := c.table.final_sym(embed)
1562 if embed_sym.kind != .struct {
1563 continue
1564 }
1565 if embed_sym.info is ast.Struct {
1566 if embed_sym.info.is_union {
1567 mut embed_union_fields := c.table.struct_fields(embed_sym)
1568 mut found := false
1569 for init_field in inited_fields {
1570 for union_field in embed_union_fields {
1571 if init_field == union_field.name && found {
1572 c.error('embed union `${embed_sym.name}` can have only one field initialised',
1573 node.pos)
1574 }
1575 if init_field == union_field.name {
1576 found = true
1577 }
1578 }
1579 }
1580 }
1581 }
1582 mut zero_struct_init := ast.StructInit{
1583 pos: node.pos
1584 typ: embed
1585 }
1586 c.struct_init(mut zero_struct_init, true, mut inited_fields)
1587 }
1588}
1589
1590// Recursively check whether the struct type field is initialized
1591fn (mut c Checker) check_ref_fields_initialized(struct_sym &ast.TypeSymbol, mut checked_types []ast.Type,
1592 linked_name string, pos &token.Pos) {
1593 if (c.pref.translated || c.file.is_translated) || struct_sym.language == .c {
1594 return
1595 }
1596 for field in c.table.struct_fields(struct_sym) {
1597 if field.typ in checked_types {
1598 continue
1599 }
1600 if field.has_default_expr {
1601 // The field is already initialized by its default expression.
1602 // Its nested reference fields should not be treated as missing.
1603 continue
1604 }
1605 if field.typ.is_ptr() && !field.typ.has_flag(.shared_f) && !field.typ.has_flag(.option) {
1606 c.error('reference field `${linked_name}.${field.name}` must be initialized (part of struct `${struct_sym.name}`)',
1607 pos)
1608 continue
1609 }
1610 sym := c.table.sym(field.typ)
1611 if sym.info is ast.Struct {
1612 if sym.language == .c {
1613 continue
1614 }
1615 if field.is_embed && sym.language == .v {
1616 // an embedded struct field
1617 continue
1618 }
1619 if field.typ.has_flag(.option) {
1620 // defaults to `none`
1621 continue
1622 }
1623 checked_types << field.typ
1624 c.check_ref_fields_initialized(sym, mut checked_types, '${linked_name}.${field.name}',
1625 pos)
1626 } else if sym.info is ast.Alias {
1627 psym := c.table.sym(sym.info.parent_type)
1628 if psym.kind == .struct {
1629 checked_types << field.typ
1630 c.check_ref_fields_initialized(psym, mut checked_types,
1631 '${linked_name}.${field.name}', pos)
1632 }
1633 }
1634 }
1635}
1636
1637// Recursively check whether the struct type field is initialized
1638// NOTE:
1639// This method is temporary and will only be called by the do_check_elements_ref_fields_initialized() method.
1640// The goal is to give only a notice, not an error, for now. After a while,
1641// when we change the notice to error, we can remove this temporary method.
1642fn (mut c Checker) check_ref_fields_initialized_note(struct_sym &ast.TypeSymbol, mut checked_types []ast.Type,
1643 linked_name string, pos &token.Pos) {
1644 if (c.pref.translated || c.file.is_translated) || struct_sym.language == .c {
1645 return
1646 }
1647 for field in c.table.struct_fields(struct_sym) {
1648 if field.typ in checked_types {
1649 continue
1650 }
1651 if field.has_default_expr {
1652 // The field is already initialized by its default expression.
1653 // Its nested reference fields should not be treated as missing.
1654 continue
1655 }
1656 if field.typ.is_ptr() && !field.typ.has_flag(.shared_f) && !field.typ.has_flag(.option) {
1657 c.note('reference field `${linked_name}.${field.name}` must be initialized (part of struct `${struct_sym.name}`)',
1658 pos)
1659 continue
1660 }
1661 sym := c.table.sym(field.typ)
1662 if sym.info is ast.Struct {
1663 if sym.language == .c {
1664 continue
1665 }
1666 if field.is_embed && sym.language == .v {
1667 // an embedded struct field
1668 continue
1669 }
1670 if field.typ.has_flag(.option) {
1671 // defaults to `none`
1672 continue
1673 }
1674 checked_types << field.typ
1675 c.check_ref_fields_initialized(sym, mut checked_types, '${linked_name}.${field.name}',
1676 pos)
1677 } else if sym.info is ast.Alias {
1678 psym := c.table.sym(sym.info.parent_type)
1679 if psym.kind == .struct {
1680 checked_types << field.typ
1681 c.check_ref_fields_initialized(psym, mut checked_types,
1682 '${linked_name}.${field.name}', pos)
1683 }
1684 }
1685 }
1686}
1687
1688fn (mut c Checker) is_anon_struct_compatible(s1 ast.Struct, s2 ast.Struct) bool {
1689 if !(s1.is_anon && s2.is_anon && s1.fields.len == s2.fields.len) {
1690 return false
1691 }
1692 mut is_compatible := true
1693 for k, field in s1.fields {
1694 if !c.check_basic(field.typ, s2.fields[k].typ) {
1695 is_compatible = false
1696 break
1697 }
1698 }
1699 return is_compatible
1700}
1701