Appearance
| 1 | namespace Syntax.Process is | |
| 2 | use Logging; | |
| 3 | use Source; | |
| 4 | ||
| 5 | use Semantic.Types.Type; | |
| 6 | ||
| 7 | use IR.Values; | |
| 8 | ||
| 9 | use Ghul.Pipes; | |
| 10 | ||
| 11 | // Compiles the member-access family of expressions: member access, | |
| 12 | // identifier resolution, `?` (has-value), `!` (unwrap) and `ref`. | |
| 13 | // Split out of COMPILE_EXPRESSIONS, which delegates the matching | |
| 14 | // visit methods here. The exception-handling wrapper of | |
| 15 | // visit(identifier) stays on the visitor; visit_identifier is the | |
| 16 | // enclosed logic. | |
| 17 | class COMPILE_ACCESS is | |
| 18 | ||
| 19 | // Depth of enclosing assert conditions during the controlled | |
| 20 | // walk in the expressions pass. A presence test on a | |
| 21 | // never-optional value inside an assert is a deliberate | |
| 22 | // runtime trap for laundered nulls, not a redundant check, | |
| 23 | // so the static-type hint stays quiet there. | |
| 24 | assert_condition_depth: int public; | |
| 25 | _logger: Logger; | |
| 26 | _symbol_table: Semantic.SYMBOL_TABLE; | |
| 27 | _symbol_loader: Semantic.SYMBOL_LOADER; | |
| 28 | _symbol_use_locations: Semantic.SYMBOL_USE_LOCATIONS; | |
| 29 | _innate_symbol_lookup: Semantic.Lookups.InnateSymbolLookup; | |
| 30 | _overload_resolver: Semantic.OVERLOAD_RESOLVER; | |
| 31 | _function_caller: Semantic.FUNCTION_CALLER; | |
| 32 | _unit_variant_constructor: Semantic.UNIT_VARIANT_CONSTRUCTOR; | |
| 33 | _flow: NARROWING_FLOW; | |
| 34 | _condition_analyzer: CONDITION_ANALYZER; | |
| 35 | _build_flags: Compiler.GLOBAL_BUILD_FLAGS; | |
| 36 | _visitor: COMPILE_EXPRESSIONS; | |
| 37 | _function_reference_resolver: Semantic.FUNCTION_REFERENCE_RESOLVER; | |
| 38 | ||
| 39 | init( | |
| 40 | logger: Logger, | |
| 41 | symbol_table: Semantic.SYMBOL_TABLE, | |
| 42 | symbol_loader: Semantic.SYMBOL_LOADER, | |
| 43 | symbol_use_locations: Semantic.SYMBOL_USE_LOCATIONS, | |
| 44 | innate_symbol_lookup: Semantic.Lookups.InnateSymbolLookup, | |
| 45 | overload_resolver: Semantic.OVERLOAD_RESOLVER, | |
| 46 | function_caller: Semantic.FUNCTION_CALLER, | |
| 47 | unit_variant_constructor: Semantic.UNIT_VARIANT_CONSTRUCTOR, | |
| 48 | flow: NARROWING_FLOW, | |
| 49 | condition_analyzer: CONDITION_ANALYZER, | |
| 50 | build_flags: Compiler.GLOBAL_BUILD_FLAGS, | |
| 51 | visitor: COMPILE_EXPRESSIONS | |
| 52 | ) is | |
| 53 | super.init(); | |
| 54 | ||
| 55 | _logger = logger; | |
| 56 | _symbol_table = symbol_table; | |
| 57 | _symbol_loader = symbol_loader; | |
| 58 | _symbol_use_locations = symbol_use_locations; | |
| 59 | _innate_symbol_lookup = innate_symbol_lookup; | |
| 60 | _overload_resolver = overload_resolver; | |
| 61 | _function_caller = function_caller; | |
| 62 | _unit_variant_constructor = unit_variant_constructor; | |
| 63 | _flow = flow; | |
| 64 | _condition_analyzer = condition_analyzer; | |
| 65 | _build_flags = build_flags; | |
| 66 | _visitor = visitor; | |
| 67 | _function_reference_resolver = Semantic.FUNCTION_REFERENCE_RESOLVER(logger, symbol_table, symbol_loader, innate_symbol_lookup, overload_resolver); | |
| 68 | si | |
| 69 | ||
| 70 | visit_member(member: Trees.Expressions.MEMBER) is | |
| 71 | let need_store = member.value? /\ isa Need.STORE(member.value); | |
| 72 | let need_deref mut = false; | |
| 73 | ||
| 74 | if member.identifier == null \/ member.identifier.is_poisoned then | |
| 75 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 76 | return; | |
| 77 | fi | |
| 78 | ||
| 79 | if member.left.value? then | |
| 80 | let left_value mut = member.left.value; | |
| 81 | let type mut = left_value.type; | |
| 82 | ||
| 83 | if type == null then | |
| 84 | _logger.poison(member.left.location, "member left has no type"); | |
| 85 | ||
| 86 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 87 | return; | |
| 88 | fi | |
| 89 | ||
| 90 | // `x?.y` never dereferences a null receiver, and | |
| 91 | // `x.has_value` is the optional protocol's presence | |
| 92 | // query — asking is not dereferencing. | |
| 93 | if !member.is_coalesce /\ !(member.identifier.name =~ "has_value") then | |
| 94 | _visitor.check_receiver_present(member.left); | |
| 95 | fi | |
| 96 | ||
| 97 | // TODO we could loop here to handle multiple levels of dereferencing | |
| 98 | if type.is_ref then | |
| 99 | need_deref = true; | |
| 100 | // is_ref implies an element type; the runtime | |
| 101 | // invariant guarantees get_element_type() non-null. | |
| 102 | type = type.get_element_type()!; | |
| 103 | ||
| 104 | left_value = DEREF(left_value, type); | |
| 105 | member.left.compile_expressions_state.value = left_value; | |
| 106 | fi | |
| 107 | ||
| 108 | // Operation-constraint inference: when the receiver | |
| 109 | // is an INFERRED_VARIABLE_TYPE placeholder, record a | |
| 110 | // MEMBER_CONSTRAINT on the placeholder's origin so | |
| 111 | // the constraint-aware LUB can later filter candidate | |
| 112 | // types to those that actually expose this member. | |
| 113 | // mark_consumed_any drives the retry loop to re-walk | |
| 114 | // the body with the resolved type (if any). | |
| 115 | if isa Semantic.Types.INFERRED_VARIABLE_TYPE(type) then | |
| 116 | let placeholder = type; | |
| 117 | ||
| 118 | _logger.mark_consumed_any_if(placeholder.origin.add_constraint(Semantic.MEMBER_CONSTRAINT(member.identifier.name))); | |
| 119 | ||
| 120 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 121 | return; | |
| 122 | fi | |
| 123 | ||
| 124 | if !isa Semantic.Types.NAMED(type) then | |
| 125 | if !isa Semantic.Types.ERROR(type) /\ !type.is_inferred then | |
| 126 | // Suppress for ERROR (existing — error already | |
| 127 | // reported, the contract says don't pile on) | |
| 128 | // and for is_inferred placeholders (deferred- | |
| 129 | // inference: the lambda's arg type is awaiting | |
| 130 | // the call-site second-pass to fill it in, | |
| 131 | // and emitting a fatal "type has no members" | |
| 132 | // here breaks that flow). Both share the | |
| 133 | // intent of "don't surface a member-resolution | |
| 134 | // failure on a stand-in type". | |
| 135 | _logger.poison(member.left.location, "type has no members: {type}"); | |
| 136 | fi | |
| 137 | ||
| 138 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 139 | return; | |
| 140 | fi | |
| 141 | ||
| 142 | let named_type mut = type; | |
| 143 | ||
| 144 | // For coalescing access against any optional, look | |
| 145 | // up the member on the unwrapped (inner) type so | |
| 146 | // `a?.b` consistently means "if a is present, access | |
| 147 | // b on the unwrapped a". A value-type optional like | |
| 148 | // NULLABLE[T] / MAYBE[T] otherwise resolves `value` | |
| 149 | // / `has_value` against the wrapper rather than the | |
| 150 | // payload, surprising the user and producing IL that | |
| 151 | // mixes wrapper-thissed calls with payload-typed | |
| 152 | // stack values. | |
| 153 | if member.is_coalesce /\ named_type.is_optional then | |
| 154 | let inner = named_type.optional_inner_type; | |
| 155 | ||
| 156 | if inner? /\ isa Semantic.Types.NAMED(inner) then | |
| 157 | named_type = inner; | |
| 158 | fi | |
| 159 | fi | |
| 160 | ||
| 161 | if named_type.scope == null then | |
| 162 | _logger.poison(member.left.location, "member left type has no type: {type}"); | |
| 163 | ||
| 164 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 165 | return; | |
| 166 | fi | |
| 167 | ||
| 168 | let symbol mut = named_type.find_member(member.identifier.name); | |
| 169 | ||
| 170 | // A member that resolves to same-name types at several | |
| 171 | // generic arities comes back as a TYPE_GROUP. In value | |
| 172 | // position (`Foo.bar` with no `[...]`) collapse to the | |
| 173 | // arity-0 member; `Foo[T].bar` is handled earlier by | |
| 174 | // GENERIC_APPLICATION before reaching here. | |
| 175 | let member_group = cast Semantic.Symbols.TYPE_GROUP?(symbol); | |
| 176 | ||
| 177 | if member_group? then | |
| 178 | let arity_zero = member_group.find_by_generic_arguments_count(0); | |
| 179 | ||
| 180 | // A constructor call on the qualified name resolves to the | |
| 181 | // group's generic member when there is no constructible | |
| 182 | // arity-0 member (a static factory class shares the name | |
| 183 | // with a generic type, `Collections.KeyValuePair`); when | |
| 184 | // the arity-0 member is itself constructible, or this is a | |
| 185 | // plain value-position access, collapse to it. | |
| 186 | let for_call = | |
| 187 | if member.is_call_target /\ (!arity_zero? \/ arity_zero.is_abstract) then | |
| 188 | member_group.sole_generic_member() | |
| 189 | else | |
| 190 | null | |
| 191 | fi; | |
| 192 | ||
| 193 | if for_call? then | |
| 194 | symbol = for_call; | |
| 195 | elif arity_zero? then | |
| 196 | symbol = arity_zero; | |
| 197 | else | |
| 198 | let counts = member_group.generic_arguments_counts |> map(a -> string => "{a}") |> join(" or "); | |
| 199 | _logger.error(member.identifier.location, "type {member.identifier.name} requires {counts} type arguments"); | |
| 200 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 201 | return; | |
| 202 | fi | |
| 203 | fi | |
| 204 | ||
| 205 | if !symbol? then | |
| 206 | let hint = try_describe_intersection_miss(named_type, member.identifier.name); | |
| 207 | ||
| 208 | if hint? then | |
| 209 | _logger.error(member.identifier.location, hint); | |
| 210 | else | |
| 211 | _logger.error(member.identifier.location, "member {member.identifier.name} not found in {named_type}"); | |
| 212 | fi | |
| 213 | ||
| 214 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 215 | return; | |
| 216 | fi | |
| 217 | ||
| 218 | _symbol_use_locations.add_symbol_use(member.identifier.right_location, symbol); | |
| 219 | ||
| 220 | if symbol.is_instance /\ !left_value.is_consumable then | |
| 221 | _logger.error(member.identifier.location, "cannot access instance member {member.identifier.name} in {named_type}"); | |
| 222 | fi | |
| 223 | ||
| 224 | _symbol_loader.find_symbol = | |
| 225 | (name: string) is | |
| 226 | let result = named_type.find_member(name); | |
| 227 | ||
| 228 | return result; | |
| 229 | si; | |
| 230 | ||
| 231 | let value: Value? mut = _; | |
| 232 | ||
| 233 | if need_store then | |
| 234 | if member.is_coalesce then | |
| 235 | _logger.error(member.location, "cannot assign through coalescing member access"); | |
| 236 | fi | |
| 237 | ||
| 238 | // A struct-typed receiver with no in-place address is a | |
| 239 | // temporary copy - a property get, method result or | |
| 240 | // indexer element - so a store through it would be | |
| 241 | // silently lost. Field chains, locals, self and refs | |
| 242 | // all carry an address and store in place. | |
| 243 | if | |
| 244 | symbol.is_instance /\ | |
| 245 | type.is_value_type /\ | |
| 246 | !left_value.has_address | |
| 247 | then | |
| 248 | _logger.error(member.location, "cannot assign through a copy of a struct value here"); | |
| 249 | ||
| 250 | member.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), member.location); | |
| 251 | return; | |
| 252 | fi | |
| 253 | ||
| 254 | let store_value = cast Need.STORE?(member.value)!.value; | |
| 255 | ||
| 256 | if check_store_access(member.location, left_value, symbol, named_type) then | |
| 257 | value = symbol.store(member.location, left_value, store_value, _symbol_loader, false); | |
| 258 | fi | |
| 259 | ||
| 260 | // The written receiver may alias any receiver a | |
| 261 | // fact was proven on, so the stored member's own | |
| 262 | // facts and every path reading through it die — | |
| 263 | // keyed on the member symbol, not the receiver. | |
| 264 | _flow.on_member_store(symbol); | |
| 265 | else | |
| 266 | let variant = cast Semantic.Symbols.VARIANT?(symbol); | |
| 267 | ||
| 268 | if variant? /\ variant.is_unit_variant then | |
| 269 | if member.is_coalesce then | |
| 270 | _logger.error(member.location, "coalescing member access does not apply to a unit-variant constructor"); | |
| 271 | fi | |
| 272 | ||
| 273 | let lowered = _unit_variant_constructor.try_load(member.location, variant, member.expected_type, member); | |
| 274 | ||
| 275 | if lowered? then | |
| 276 | _symbol_use_locations.add_symbol_use(member.identifier.right_location, lowered.constructor); | |
| 277 | member.compile_expressions_state.value = lowered.value; | |
| 278 | return; | |
| 279 | fi | |
| 280 | fi | |
| 281 | ||
| 282 | if check_load_access(member.location, left_value, symbol, named_type) then | |
| 283 | if member.is_coalesce then | |
| 284 | value = _build_coalesce_load(member, symbol); | |
| 285 | ||
| 286 | if value? then | |
| 287 | member.compile_expressions_state.value = value; | |
| 288 | return; | |
| 289 | fi | |
| 290 | ||
| 291 | // Fallthrough on a build failure (e.g. | |
| 292 | // unsupported receiver shape): proceed with | |
| 293 | // a plain access so the user gets at most | |
| 294 | // one diagnostic instead of a cascade. | |
| 295 | value = symbol.load(member.location, left_value, _symbol_loader); | |
| 296 | else | |
| 297 | value = | |
| 298 | _function_reference_resolver.try_load(member.location, symbol, left_value, member.expected_type, member.is_call_target) ?? | |
| 299 | symbol.load(member.location, left_value, _symbol_loader); | |
| 300 | fi | |
| 301 | fi | |
| 302 | fi | |
| 303 | ||
| 304 | member.compile_expressions_state.value = value; | |
| 305 | ||
| 306 | // Path narrowing: when the flow analysis has recorded | |
| 307 | // facts for this member-access path, surface the | |
| 308 | // access at the narrower view type so | |
| 309 | // `if isa Cat(x.y) then x.y.meow() fi` and | |
| 310 | // `if x.y? then x.y.z fi` both type-check. Mirrors the | |
| 311 | // local-variable path in visit_identifier. A reference | |
| 312 | // optional shares IL with its non-optional form (a type | |
| 313 | // view); NULLABLE[T] / MAYBE[T] get a `.value` | |
| 314 | // projection. | |
| 315 | if !need_store /\ member.value? then | |
| 316 | let path = _visitor.try_build_access_path(member); | |
| 317 | ||
| 318 | if path? then | |
| 319 | // Step 1: type narrow (isa T on x.y). Wraps the | |
| 320 | // loaded value at the recorded static subtype | |
| 321 | // when the composition is sound. | |
| 322 | if let recorded = _flow.narrowed_type_of_path(path) then | |
| 323 | let loaded = member.value!; | |
| 324 | ||
| 325 | if loaded.type? then | |
| 326 | if let composed = _flow.compose_path_narrow(loaded.type, recorded) then | |
| 327 | member.compile_expressions_state.value = IR.Values.NARROW_VIEW(loaded, composed); | |
| 328 | _symbol_use_locations.replace_with_variable_use(member.identifier.right_location, symbol, member.value!); | |
| 329 | fi | |
| 330 | fi | |
| 331 | fi | |
| 332 | ||
| 333 | // Step 2: presence narrow (if x.y? then x.y). | |
| 334 | // Reads member.value again in case step 1 | |
| 335 | // already wrapped it. | |
| 336 | let loaded = member.value!; | |
| 337 | ||
| 338 | if loaded.type? /\ loaded.type!.is_optional /\ _flow.is_non_null_path(path) then | |
| 339 | let loaded_type = loaded.type!; | |
| 340 | let narrowed = loaded_type.as_non_optional(); | |
| 341 | ||
| 342 | if !narrowed.is_optional then | |
| 343 | member.compile_expressions_state.value = IR.Values.NARROW_VIEW(loaded, narrowed); | |
| 344 | // Overwrite the earlier symbol-use entry so | |
| 345 | // HOVER on the member surfaces the narrowed | |
| 346 | // type — mirroring what visit_identifier does | |
| 347 | // for a narrowed local. Same location; put | |
| 348 | // wins for the last write. | |
| 349 | _symbol_use_locations.replace_with_variable_use(member.identifier.right_location, symbol, member.value!); | |
| 350 | elif loaded_type.is_value_type then | |
| 351 | let value_member = loaded_type.find_member("value"); | |
| 352 | ||
| 353 | if value_member? then | |
| 354 | let projected = value_member.load(member.location, loaded, _symbol_loader); | |
| 355 | ||
| 356 | member.compile_expressions_state.value = IR.Values.NARROW_PROJECT(loaded, projected); | |
| 357 | _symbol_use_locations.replace_with_variable_use(member.identifier.right_location, symbol, member.value!); | |
| 358 | fi | |
| 359 | fi | |
| 360 | fi | |
| 361 | fi | |
| 362 | fi | |
| 363 | fi | |
| 364 | si | |
| 365 | ||
| 366 | // True iff any receiver in `expr`'s member-access chain has | |
| 367 | // been wrapped in a NARROW_VIEW by path narrowing. Used to | |
| 368 | // recognise loads whose result type reflects a narrowed | |
| 369 | // receiver — the declared receiver type is still optional at | |
| 370 | // this position, so an `!` against the narrowed type is | |
| 371 | // redundant rather than an error. | |
| 372 | _has_narrowed_receiver(expr: Trees.Expressions.Expression) -> bool is | |
| 373 | let cursor mut = expr; | |
| 374 | ||
| 375 | while isa Trees.Expressions.MEMBER(cursor) do | |
| 376 | let member = cast Trees.Expressions.MEMBER(cursor); | |
| 377 | ||
| 378 | if member.left.value? /\ isa IR.Values.NARROW_VIEW(member.left.value) then | |
| 379 | return true; | |
| 380 | fi | |
| 381 | ||
| 382 | cursor = member.left; | |
| 383 | od | |
| 384 | ||
| 385 | return false; | |
| 386 | si | |
| 387 | ||
| 388 | check_load_access(location: LOCATION, from: Value?, symbol: Semantic.Symbols.Symbol, type: Type) -> bool is | |
| 389 | if !symbol.is_accessible_to(_symbol_table.current_accessor) then | |
| 390 | _logger.error(location, "{symbol} is not accessible here"); | |
| 391 | // The member is assembly-reachable, so let the access through to | |
| 392 | // avoid a cascade of downstream errors: the diagnostic stands but | |
| 393 | // the generated IL is still valid. | |
| 394 | return true; | |
| 395 | fi | |
| 396 | ||
| 397 | if symbol.is_public_readable then | |
| 398 | return true; | |
| 399 | fi | |
| 400 | ||
| 401 | if from? /\ from.is_self then | |
| 402 | return true; | |
| 403 | fi | |
| 404 | ||
| 405 | let instance_context = _symbol_table.current_instance_context; | |
| 406 | let instance_context_type = if instance_context? then instance_context.type else null fi; | |
| 407 | ||
| 408 | if instance_context_type? /\ instance_context_type.is_assignable_from(type) then | |
| 409 | return true; | |
| 410 | fi | |
| 411 | ||
| 412 | _logger.error(location, "{symbol} is not publicly readable"); | |
| 413 | ||
| 414 | return false; | |
| 415 | si | |
| 416 | ||
| 417 | check_store_access(location: LOCATION, from: Value?, symbol: Semantic.Symbols.Symbol, type: Type) -> bool is | |
| 418 | if !symbol.is_accessible_to(_symbol_table.current_accessor) then | |
| 419 | _logger.error(location, "{symbol} is not accessible here"); | |
| 420 | // Assembly-reachable: allow the store so the diagnostic does not | |
| 421 | // cascade into follow-on errors. | |
| 422 | return true; | |
| 423 | fi | |
| 424 | ||
| 425 | if !symbol.is_private /\ !symbol.is_field then | |
| 426 | return true; | |
| 427 | fi | |
| 428 | ||
| 429 | if from? /\ from.is_self then | |
| 430 | return true; | |
| 431 | fi | |
| 432 | ||
| 433 | let instance_context = _symbol_table.current_instance_context; | |
| 434 | let instance_context_type = if instance_context? then instance_context.type else null fi; | |
| 435 | ||
| 436 | if instance_context_type? /\ instance_context_type.is_assignable_from(type) then | |
| 437 | return true; | |
| 438 | fi | |
| 439 | ||
| 440 | _logger.error(location, "{symbol} is not publicly assignable"); | |
| 441 | ||
| 442 | return false; | |
| 443 | si | |
| 444 | ||
| 445 | visit_identifier(identifier: Trees.Expressions.IDENTIFIER) is | |
| 446 | let need_store = identifier.value? /\ isa Need.STORE(identifier.value); | |
| 447 | ||
| 448 | let symbol mut = _visitor.find(identifier.identifier); | |
| 449 | ||
| 450 | if let shadowed = symbol, callable = _try_find_shadowed_callable(identifier, shadowed) then | |
| 451 | symbol = callable; | |
| 452 | fi | |
| 453 | ||
| 454 | let group = cast Semantic.Symbols.TYPE_GROUP?(symbol); | |
| 455 | ||
| 456 | if group? then | |
| 457 | let bare = group.find_by_generic_arguments_count(0); | |
| 458 | ||
| 459 | // A constructor call on the bare name resolves to the group's | |
| 460 | // generic member when there is no constructible arity-0 | |
| 461 | // member — the reflected shape where a static factory class | |
| 462 | // (abstract, so not constructible) shares a name with a | |
| 463 | // generic type (`KeyValuePair` + `KeyValuePair[K,V]`). When | |
| 464 | // the arity-0 member *is* constructible (a plain non-generic | |
| 465 | // class overloaded with a generic one, `FOO` + `FOO[T]`), or | |
| 466 | // this is a plain value-position reference, collapse to it. | |
| 467 | let for_call = | |
| 468 | if identifier.is_call_target /\ (!bare? \/ bare.is_abstract) then | |
| 469 | group.sole_generic_member() | |
| 470 | else | |
| 471 | null | |
| 472 | fi; | |
| 473 | ||
| 474 | if for_call? then | |
| 475 | symbol = for_call; | |
| 476 | elif bare? then | |
| 477 | symbol = bare; | |
| 478 | else | |
| 479 | let counts = group.generic_arguments_counts |> map(a -> string => "{a}") |> join(" or "); | |
| 480 | _logger.error(identifier.location, "type {identifier.identifier} requires {counts} type arguments"); | |
| 481 | identifier.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), identifier.location); | |
| 482 | return; | |
| 483 | fi | |
| 484 | fi | |
| 485 | ||
| 486 | if symbol? then | |
| 487 | if symbol.is_type then | |
| 488 | _symbol_use_locations.add_symbol_use(identifier.right_location, symbol); | |
| 489 | ||
| 490 | let variant = cast Semantic.Symbols.VARIANT?(symbol); | |
| 491 | ||
| 492 | if variant? /\ variant.is_unit_variant then | |
| 493 | let lowered = _unit_variant_constructor.try_load(identifier.location, variant, identifier.expected_type, identifier); | |
| 494 | ||
| 495 | if lowered? then | |
| 496 | // Anchor HOVER and find-references to the | |
| 497 | // specialised init so the rendered owner | |
| 498 | // carries the resolved type arguments — | |
| 499 | // matching the parenthesised path's | |
| 500 | // bookkeeping in resolve_constructor. | |
| 501 | _symbol_use_locations.add_symbol_use(identifier.right_location, lowered.constructor); | |
| 502 | identifier.compile_expressions_state.value = lowered.value; | |
| 503 | return; | |
| 504 | fi | |
| 505 | fi | |
| 506 | ||
| 507 | let symbol_type = symbol.type; | |
| 508 | ||
| 509 | if symbol_type? then | |
| 510 | identifier.compile_expressions_state.value = TYPE_EXPRESSION(symbol_type, identifier.location); | |
| 511 | else | |
| 512 | identifier.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), identifier.location); | |
| 513 | fi | |
| 514 | else | |
| 515 | // Bare-identifier (implicit-self) access to a field, including | |
| 516 | // an inherited underscore field, is subject to the same policy | |
| 517 | // as explicit member access. Log but allow: the field is | |
| 518 | // assembly-reachable, so blocking would only cascade. | |
| 519 | if symbol.is_field /\ !symbol.is_accessible_to(_symbol_table.current_accessor) then | |
| 520 | _logger.error(identifier.location, "{symbol} is not accessible here"); | |
| 521 | fi | |
| 522 | ||
| 523 | _symbol_loader.find_symbol = (name: string) => _visitor.find(name); | |
| 524 | ||
| 525 | if need_store then | |
| 526 | let store_value = cast Need.STORE?(identifier.value)!.value; | |
| 527 | identifier.compile_expressions_state.value = symbol.store(identifier.location, null, store_value, _symbol_loader, false); | |
| 528 | ||
| 529 | // Optional-narrowing, write side: a | |
| 530 | // non-optional right-hand side leaves a | |
| 531 | // declared-optional target known to hold a | |
| 532 | // value, so HOVER on the target describes | |
| 533 | // the state the assignment leaves behind — | |
| 534 | // agreeing with what a subsequent read | |
| 535 | // reports rather than with the declared | |
| 536 | // type. Gated on the same target shape the | |
| 537 | // flow analysis narrows, so hover never | |
| 538 | // claims a narrow that isn't applied. | |
| 539 | let narrowed: Semantic.Types.Type? mut = null; | |
| 540 | ||
| 541 | let target = _visitor.try_get_narrowing_target(identifier); | |
| 542 | ||
| 543 | if target? /\ _visitor.is_non_optional_value(store_value) then | |
| 544 | let declared = _flow.declared_type_of(target); | |
| 545 | ||
| 546 | if declared? /\ declared.is_optional then | |
| 547 | let inner = declared.optional_inner_type; | |
| 548 | ||
| 549 | if inner? /\ !inner.is_optional then | |
| 550 | narrowed = inner; | |
| 551 | fi | |
| 552 | fi | |
| 553 | fi | |
| 554 | ||
| 555 | if narrowed? then | |
| 556 | _symbol_use_locations.add_variable_use(identifier.right_location, symbol, narrowed); | |
| 557 | else | |
| 558 | _symbol_use_locations.add_symbol_use(identifier.right_location, symbol); | |
| 559 | fi | |
| 560 | else | |
| 561 | identifier.compile_expressions_state.value = | |
| 562 | _function_reference_resolver.try_load(identifier.location, symbol, null, identifier.expected_type, identifier.is_call_target) ?? | |
| 563 | symbol.load(identifier.location, null, _symbol_loader); | |
| 564 | ||
| 565 | // Optional-narrowing: when flow analysis has | |
| 566 | // established this variable is non-null here, | |
| 567 | // surface the use as the non-optional type. | |
| 568 | // Reference `T?` is a NAMED-with-flag — IL | |
| 569 | // representation matches `T`, so the load gets | |
| 570 | // a type-view snapshot (mirrors how `isa`- | |
| 571 | // narrowing reaches the load via a mutated | |
| 572 | // `symbol.type`). The value-type lowerings | |
| 573 | // (`NULLABLE[T]` / `MAYBE[T]`) are wrapper | |
| 574 | // structs, so the load gets wrapped in | |
| 575 | // `NARROW_PROJECT` — emits `.value` at gen | |
| 576 | // time, but `visit_has_value` and | |
| 577 | // `visit_unwrap` can peel back to the | |
| 578 | // underlying wrapper for their own IR. | |
| 579 | let loaded = identifier.value; | |
| 580 | ||
| 581 | // the load's snapshot type is null for an inference placeholder | |
| 582 | @suppress("presence-test-non-optional") | |
| 583 | if | |
| 584 | isa Semantic.Symbols.Variable(symbol) /\ | |
| 585 | isa IR.Values.Load.SYMBOL(loaded) /\ | |
| 586 | loaded.type? /\ | |
| 587 | loaded.type.is_optional | |
| 588 | then | |
| 589 | let variable = symbol; | |
| 590 | ||
| 591 | if _flow.is_non_null(variable) then | |
| 592 | let loaded_type = loaded.type; | |
| 593 | let narrowed = loaded_type.as_non_optional(); | |
| 594 | ||
| 595 | if !narrowed.is_optional then | |
| 596 | (cast IR.Values.Load.SYMBOL(loaded)).narrow_snapshot_type(narrowed); | |
| 597 | elif loaded_type.is_value_type then | |
| 598 | let value_member = loaded_type.find_member("value"); | |
| 599 | ||
| 600 | if value_member? then | |
| 601 | let projected = value_member.load(identifier.location, loaded, _symbol_loader); | |
| 602 | ||
| 603 | identifier.compile_expressions_state.value = IR.Values.NARROW_PROJECT(loaded, projected); | |
| 604 | fi | |
| 605 | fi | |
| 606 | fi | |
| 607 | fi | |
| 608 | ||
| 609 | // HOVER reads a narrowed local's type off | |
| 610 | // this use-site node, not the symbol — the | |
| 611 | // symbol's `type` is restored after the walk. | |
| 612 | _symbol_use_locations.add_variable_use(identifier.right_location, symbol, identifier.value!); | |
| 613 | ||
| 614 | // Definite assignment: reading a tracked | |
| 615 | // deferred-init local before it is assigned | |
| 616 | // on every path reaching here. An address-of | |
| 617 | // operand of `ref` is not a value read — its | |
| 618 | // read-or-write is decided by the resolved call. | |
| 619 | if | |
| 620 | !_build_flags.no_warn_definite_assignment /\ | |
| 621 | isa Semantic.Symbols.Variable(symbol) /\ | |
| 622 | !_visitor.is_reference_operand_target(symbol) | |
| 623 | then | |
| 624 | let variable = symbol; | |
| 625 | ||
| 626 | if _flow.is_tracked(variable) /\ !_flow.is_assigned(variable) then | |
| 627 | _logger.warn(identifier.location, "definite-assignment", "{variable.name} may be used before it is assigned"); | |
| 628 | fi | |
| 629 | fi | |
| 630 | fi | |
| 631 | fi | |
| 632 | ||
| 633 | else | |
| 634 | identifier.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), identifier.location); | |
| 635 | fi | |
| 636 | si | |
| 637 | ||
| 638 | // A bare name in call position that resolved to something that | |
| 639 | // cannot be called - a local, field or property that holds no | |
| 640 | // function - looks past it for a callable of the same name | |
| 641 | // further out, so a value does not hide a function it shares a | |
| 642 | // name with. Returns null to leave resolution as it was, which | |
| 643 | // is every case but the shadowed one. | |
| 644 | // | |
| 645 | // Deliberately narrow: only a symbol that is not callable at all | |
| 646 | // qualifies. A function group whose overloads do not accept the | |
| 647 | // supplied arguments is left alone, so a genuine argument | |
| 648 | // mismatch still reports as one rather than silently calling | |
| 649 | // something else. | |
| 650 | _try_find_shadowed_callable( | |
| 651 | identifier: Trees.Expressions.IDENTIFIER, | |
| 652 | symbol: Semantic.Symbols.Symbol | |
| 653 | ) -> Semantic.Symbols.Symbol? is | |
| 654 | if | |
| 655 | !identifier.is_call_target \/ | |
| 656 | identifier.identifier.qualifier? \/ | |
| 657 | Semantic.SYMBOL_TABLE.is_callable_symbol(symbol) | |
| 658 | then | |
| 659 | return null; | |
| 660 | fi | |
| 661 | ||
| 662 | // A local read before its own initializer has completed | |
| 663 | // holds no value to call, whatever type it ends up with - | |
| 664 | // the case a `let` whose initializer calls the name it is | |
| 665 | // declaring runs into. Its type is still an inference | |
| 666 | // placeholder at this point, so it is settled here, ahead | |
| 667 | // of the sentinel test below. | |
| 668 | // | |
| 669 | // Restricted to a reference in the same capture context as | |
| 670 | // the declaration: inside a nested literal the same shape | |
| 671 | // is a lambda referring to itself, where reaching a | |
| 672 | // like-named function further out would be a surprise, so | |
| 673 | // that keeps its existing error. | |
| 674 | let is_uninitialized_local mut = false; | |
| 675 | ||
| 676 | if let variable: Semantic.Symbols.Variable = symbol /\ !variable.is_defined then | |
| 677 | if _symbol_table.current_capture_context != cast Semantic.Symbols.Symbol?(variable.owner) then | |
| 678 | return null; | |
| 679 | fi | |
| 680 | ||
| 681 | is_uninitialized_local = true; | |
| 682 | fi | |
| 683 | ||
| 684 | // Otherwise a sentinel type says the slot's type is not | |
| 685 | // known - inference has not settled it, or it failed and | |
| 686 | // was poisoned. Neither is evidence that the symbol holds | |
| 687 | // no function, and looking past a symbol whose declaration | |
| 688 | // already reported an error would add a second diagnostic | |
| 689 | // about the first one's consequence. | |
| 690 | if | |
| 691 | let typed: Semantic.Types.Typed = symbol /\ | |
| 692 | !is_uninitialized_local /\ | |
| 693 | (typed.type?.is_sentinel ?? false) | |
| 694 | then | |
| 695 | return null; | |
| 696 | fi | |
| 697 | ||
| 698 | let callable = _symbol_table.find_enclosing_callable(identifier.identifier.name); | |
| 699 | ||
| 700 | if !callable? \/ callable == symbol then | |
| 701 | return null; | |
| 702 | fi | |
| 703 | ||
| 704 | _logger.warn( | |
| 705 | identifier.location, | |
| 706 | "shadowed-non-callable", | |
| 707 | "{identifier.identifier.name} is not callable here, calling the one from an enclosing scope instead" | |
| 708 | ); | |
| 709 | ||
| 710 | return callable; | |
| 711 | si | |
| 712 | ||
| 713 | visit_has_value(has_value: Trees.Expressions.HAS_VALUE) is | |
| 714 | ||
| 715 | if !has_value.left.value? then | |
| 716 | _logger.poison(has_value.left.location, "has value expression has no value"); | |
| 717 | has_value.compile_expressions_state.value = DUMMY(_innate_symbol_lookup.get_bool_type(), has_value.location); | |
| 718 | return; | |
| 719 | fi | |
| 720 | ||
| 721 | if | |
| 722 | !has_value.left.value.check_is_consumable(_logger, has_value.left.location) | |
| 723 | then | |
| 724 | _logger.error(has_value.left.location, "cannot use this here"); | |
| 725 | has_value.compile_expressions_state.value = DUMMY(_innate_symbol_lookup.get_bool_type(), has_value.location); | |
| 726 | return; | |
| 727 | fi | |
| 728 | ||
| 729 | // Peel a flow-narrowing projection back to its wrapper so | |
| 730 | // `has_value` lookup hits the wrapper's bool field. | |
| 731 | has_value.left.compile_expressions_state.value = IR.Values.NARROW_PROJECT.peel(has_value.left.value!); | |
| 732 | ||
| 733 | let left_value = has_value.left.value!; | |
| 734 | let bool_type = _innate_symbol_lookup.get_bool_type(); | |
| 735 | ||
| 736 | // Union `u?` → `isa Default(u)`. Both source-defined | |
| 737 | // and cross-asm unions carry the default variant on the | |
| 738 | // symbol; cross-asm unions get it via the | |
| 739 | // `DEFAULT_VARIANT_ATTRIBUTE` marker read in | |
| 740 | // `SYMBOL_FACTORY.materialize_variant`. A union without | |
| 741 | // a default variant short-circuits to a bare null check | |
| 742 | // — `value`/`has_value` are no longer the convention | |
| 743 | // for unions. | |
| 744 | if !left_value.type!.is_value_type then | |
| 745 | let classy = _condition_analyzer.get_classy_for_narrowing(left_value.type); | |
| 746 | ||
| 747 | if classy? /\ (classy.is_union \/ classy.is_variant) then | |
| 748 | let default_variant = _get_default_variant_for_operand(classy); | |
| 749 | ||
| 750 | if default_variant? then | |
| 751 | has_value.compile_expressions_state.value = | |
| 752 | _build_default_variant_isa( | |
| 753 | has_value.location, | |
| 754 | left_value, | |
| 755 | default_variant, | |
| 756 | bool_type | |
| 757 | ); | |
| 758 | else | |
| 759 | has_value.compile_expressions_state.value = HAS_VALUE(left_value, bool_type); | |
| 760 | fi | |
| 761 | ||
| 762 | return; | |
| 763 | fi | |
| 764 | fi | |
| 765 | ||
| 766 | let has_value_member = | |
| 767 | left_value.type!.find_member("has_value"); | |
| 768 | let has_value_valid mut = false; | |
| 769 | ||
| 770 | if has_value_member? then | |
| 771 | if !isa Semantic.Symbols.Property(has_value_member) then | |
| 772 | _logger.error( | |
| 773 | has_value.left.location, | |
| 774 | "has_value member must be a bool property" | |
| 775 | ); | |
| 776 | elif !has_value_member.type!.matches(bool_type) then | |
| 777 | _logger.error( | |
| 778 | has_value.left.location, | |
| 779 | "has_value property must be bool" | |
| 780 | ); | |
| 781 | else | |
| 782 | has_value_valid = true; | |
| 783 | fi | |
| 784 | fi | |
| 785 | ||
| 786 | let target = _visitor.try_get_narrowing_target(has_value.left); | |
| 787 | ||
| 788 | if left_value.type!.is_optional then | |
| 789 | // the test that itself proves presence is not | |
| 790 | // redundant; one on an operand already proven to | |
| 791 | // hold a value is | |
| 792 | if target? /\ _flow.is_non_null(target) then | |
| 793 | _logger.warn( | |
| 794 | has_value.location, | |
| 795 | "redundant-presence-test", | |
| 796 | "'?' is redundant here" | |
| 797 | ); | |
| 798 | fi | |
| 799 | elif !has_value_member? then | |
| 800 | // no live has_value layer to consult: a non-optional | |
| 801 | // operand narrowed from optional gets the flow-specific | |
| 802 | // "redundant here"; a never-optional value type is an | |
| 803 | // error; a never-optional reference is redundant by its | |
| 804 | // static type and gets the plain "redundant" - the type | |
| 805 | // guarantees presence everywhere, not just here. | |
| 806 | let declared = if target? then _flow.declared_type_of(target) else null fi; | |
| 807 | ||
| 808 | if declared? /\ declared.is_optional then | |
| 809 | _logger.warn( | |
| 810 | has_value.location, | |
| 811 | "redundant-presence-test", | |
| 812 | "'?' is redundant here" | |
| 813 | ); | |
| 814 | elif left_value.type!.is_value_type then | |
| 815 | _logger.error(has_value.left.location, "not optional"); | |
| 816 | has_value.compile_expressions_state.value = DUMMY(bool_type, has_value.location); | |
| 817 | return; | |
| 818 | elif assert_condition_depth == 0 then | |
| 819 | _logger.warn( | |
| 820 | has_value.location, | |
| 821 | "presence-test-non-optional", | |
| 822 | "'?' is redundant" | |
| 823 | ); | |
| 824 | fi | |
| 825 | fi | |
| 826 | ||
| 827 | if !left_value.type!.is_value_type then | |
| 828 | has_value.compile_expressions_state.value = | |
| 829 | get_reference_has_value( | |
| 830 | has_value.location, | |
| 831 | left_value, | |
| 832 | if has_value_valid then has_value_member else null fi, | |
| 833 | bool_type | |
| 834 | ); | |
| 835 | elif has_value_member? then | |
| 836 | if has_value_valid then | |
| 837 | has_value.compile_expressions_state.value = | |
| 838 | has_value_member.load( | |
| 839 | has_value.location, | |
| 840 | left_value, | |
| 841 | _symbol_loader | |
| 842 | ); | |
| 843 | else | |
| 844 | has_value.compile_expressions_state.value = DUMMY(bool_type, has_value.location); | |
| 845 | fi | |
| 846 | fi | |
| 847 | si | |
| 848 | ||
| 849 | visit_unwrap(unwrap: Trees.Expressions.UNWRAP) is | |
| 850 | let need_store = unwrap.value? /\ isa Need.STORE(unwrap.value); | |
| 851 | ||
| 852 | // Peel a flow-narrowing projection back to its wrapper so | |
| 853 | // `!` runs against the optional shape it was designed for | |
| 854 | // (avoids "no value member" on the already-projected `T`). | |
| 855 | unwrap.left.compile_expressions_state.value = IR.Values.NARROW_PROJECT.peel(unwrap.left.value); | |
| 856 | ||
| 857 | let unwrap_left_value = unwrap.left.value; | |
| 858 | ||
| 859 | if !unwrap_left_value? \/ !unwrap_left_value.type? then | |
| 860 | _logger.poison(unwrap.left.location, "unwrap expression has no value"); | |
| 861 | unwrap.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), unwrap.location); | |
| 862 | return; | |
| 863 | fi | |
| 864 | ||
| 865 | if | |
| 866 | !unwrap_left_value.check_is_consumable(_logger, unwrap.left.location) | |
| 867 | then | |
| 868 | _logger.error(unwrap.left.location, "cannot use this here"); | |
| 869 | unwrap.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), unwrap.location); | |
| 870 | return; | |
| 871 | fi | |
| 872 | ||
| 873 | if unwrap_left_value.type!.is_ref then | |
| 874 | // is_ref implies element type per the runtime invariant | |
| 875 | let element_type = unwrap_left_value.type!.get_element_type()!; | |
| 876 | ||
| 877 | if need_store then | |
| 878 | let store_value = cast Need.STORE?(unwrap.value)!.value; | |
| 879 | unwrap.compile_expressions_state.value = IR.Values.Store.INDIRECT(unwrap_left_value, store_value, element_type); | |
| 880 | else | |
| 881 | unwrap.compile_expressions_state.value = DEREF(unwrap_left_value, element_type); | |
| 882 | fi | |
| 883 | ||
| 884 | return; | |
| 885 | fi | |
| 886 | ||
| 887 | let value_member = unwrap_left_value.type!.find_member("value"); | |
| 888 | ||
| 889 | if !unwrap_left_value.type!.is_value_type then | |
| 890 | let classy = _condition_analyzer.get_classy_for_narrowing(unwrap_left_value.type); | |
| 891 | let default_variant = _get_default_variant_for_operand(classy); | |
| 892 | ||
| 893 | if classy? /\ default_variant? then | |
| 894 | // Union `u!` → cast to the default variant (no | |
| 895 | // IL cast when the operand is already narrowed | |
| 896 | // to that variant), with single-field projection | |
| 897 | // so the canonical "unwrap to the sole field" | |
| 898 | // rule is preserved. | |
| 899 | unwrap.compile_expressions_state.value = | |
| 900 | _build_default_variant_unwrap( | |
| 901 | unwrap.location, | |
| 902 | unwrap_left_value, | |
| 903 | classy, | |
| 904 | default_variant | |
| 905 | ); | |
| 906 | else | |
| 907 | // a plain reference type: `!` only asserts non-null. | |
| 908 | // The result type drops the `?` so an inferred `let` | |
| 909 | // binding or a non-optional slot downstream sees a | |
| 910 | // present value rather than a may-be-null one. | |
| 911 | // TODO we could do an explicit null check here: | |
| 912 | let left_value = unwrap_left_value; | |
| 913 | ||
| 914 | if left_value.type!.is_optional then | |
| 915 | unwrap.compile_expressions_state.value = TYPE_WRAPPER(left_value.type!.as_non_optional(), left_value); | |
| 916 | elif value_member? /\ left_value.type!.find_member("has_value")? then | |
| 917 | // an option-shaped reference type: flow | |
| 918 | // analysis does not track its has_value | |
| 919 | // layer, so `!` re-asserts it and is never | |
| 920 | // redundant. | |
| 921 | unwrap.compile_expressions_state.value = left_value; | |
| 922 | else | |
| 923 | let target = _visitor.try_get_narrowing_target(unwrap.left); | |
| 924 | let declared = if target? then _flow.declared_type_of(target) else null fi; | |
| 925 | ||
| 926 | // A NARROW_VIEW is a member-access path read | |
| 927 | // at its non-optional type because a path | |
| 928 | // fact holds here — the declared member is | |
| 929 | // optional, so the unwrap is redundant, not | |
| 930 | // an error. A load whose receiver chain | |
| 931 | // contains a NARROW_VIEW is the same case one | |
| 932 | // hop deeper: the load resolved a member on a | |
| 933 | // narrowed receiver, so its result type | |
| 934 | // reflects the narrow rather than the | |
| 935 | // declared receiver type. | |
| 936 | if declared? /\ declared.is_optional \/ isa IR.Values.NARROW_VIEW(left_value) \/ _has_narrowed_receiver(unwrap.left) then | |
| 937 | // non-optional only because flow analysis | |
| 938 | // has narrowed it at this point | |
| 939 | if !_build_flags.no_warn_redundant_unwrap then | |
| 940 | _logger.warn( | |
| 941 | unwrap.location, | |
| 942 | "redundant-unwrap", | |
| 943 | "'!' is redundant here" | |
| 944 | ); | |
| 945 | fi | |
| 946 | ||
| 947 | unwrap.compile_expressions_state.value = left_value; | |
| 948 | else | |
| 949 | _logger.error(unwrap.left.location, "cannot unwrap this"); | |
| 950 | unwrap.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), unwrap.location); | |
| 951 | fi | |
| 952 | fi | |
| 953 | fi | |
| 954 | elif value_member? then | |
| 955 | // TODO we could do an explicit has-value check here: | |
| 956 | if | |
| 957 | !_build_flags.no_warn_redundant_unwrap /\ | |
| 958 | unwrap_left_value.type!.is_optional | |
| 959 | then | |
| 960 | let unwrap_target = _visitor.try_get_narrowing_target(unwrap.left); | |
| 961 | ||
| 962 | if unwrap_target? /\ _flow.is_non_null(unwrap_target) then | |
| 963 | _logger.warn( | |
| 964 | unwrap.location, | |
| 965 | "redundant-unwrap", | |
| 966 | "'!' is redundant here" | |
| 967 | ); | |
| 968 | fi | |
| 969 | fi | |
| 970 | ||
| 971 | unwrap.compile_expressions_state.value = value_member.load(unwrap.location, unwrap_left_value, _symbol_loader); | |
| 972 | else | |
| 973 | _logger.error(unwrap.left.location, "cannot unwrap this"); | |
| 974 | unwrap.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), unwrap.location); | |
| 975 | fi | |
| 976 | ||
| 977 | // `x!` asserts `x` holds a value — record it, so a | |
| 978 | // subsequent dereference of `x` is not flagged. Skipped | |
| 979 | // when the target's current type is already non-optional | |
| 980 | // (the redundant-unwrap warning fires separately at that | |
| 981 | // site; recording the presence bit only grows every | |
| 982 | // downstream env for nothing). | |
| 983 | let target = _visitor.try_get_narrowing_target(unwrap.left); | |
| 984 | let target_type = if target? then target.type else null fi; | |
| 985 | ||
| 986 | if target? /\ target_type? /\ target_type.is_optional then | |
| 987 | _flow.mark_non_null(target); | |
| 988 | _flow.report_narrowing_site( | |
| 989 | unwrap.location, | |
| 990 | "narrowing-unwrap", | |
| 991 | "►", | |
| 992 | INLAY_TYPE.render(target_type.as_non_optional()) | |
| 993 | ); | |
| 994 | fi | |
| 995 | ||
| 996 | // TODO, we could handle ref and ptr here as well | |
| 997 | si | |
| 998 | ||
| 999 | visit_reference(reference: Trees.Expressions.REFERENCE) is | |
| 1000 | let left_value = reference.left.value; | |
| 1001 | ||
| 1002 | if !left_value? \/ !left_value.type? then | |
| 1003 | _logger.poison(reference.left.location, "reference expression has no value"); | |
| 1004 | reference.compile_expressions_state.value = DUMMY(Semantic.Types.ERROR(), reference.location); | |
| 1005 | return; | |
| 1006 | elif !left_value.has_address then | |
| 1007 | _logger.warn(reference.left.location, "reference-to-expression", "reference to an expression"); | |
| 1008 | fi | |
| 1009 | ||
| 1010 | left_value.check_is_consumable(_logger, reference.left.location); | |
| 1011 | ||
| 1012 | reference.compile_expressions_state.value = ADDRESS(left_value, _innate_symbol_lookup.get_reference_type(left_value.type!)); | |
| 1013 | si | |
| 1014 | ||
| 1015 | get_reference_has_value( | |
| 1016 | location: LOCATION, | |
| 1017 | value: Value, | |
| 1018 | member: Semantic.Symbols.Symbol?, | |
| 1019 | bool_type: Type | |
| 1020 | ) -> Value is | |
| 1021 | let null_check = HAS_VALUE(value, bool_type); | |
| 1022 | ||
| 1023 | if member? then | |
| 1024 | let member_check = member.load(location, value, _symbol_loader); | |
| 1025 | ||
| 1026 | let and_identifier = Trees.Identifiers.Identifier(location, "/\\"); | |
| 1027 | let and_symbol = _visitor.find(and_identifier); | |
| 1028 | ||
| 1029 | if and_symbol? /\ isa Semantic.Symbols.FUNCTION_GROUP(and_symbol) then | |
| 1030 | _symbol_loader.find_symbol = (name: string) => _visitor.find(name); | |
| 1031 | ||
| 1032 | let argument_types = Collections.LIST[Type](); | |
| 1033 | argument_types.add(bool_type); | |
| 1034 | argument_types.add(bool_type); | |
| 1035 | ||
| 1036 | let overload_result = | |
| 1037 | _overload_resolver.resolve( | |
| 1038 | location, | |
| 1039 | and_symbol, | |
| 1040 | argument_types, | |
| 1041 | false, | |
| 1042 | false, | |
| 1043 | false | |
| 1044 | ); | |
| 1045 | ||
| 1046 | if overload_result? then | |
| 1047 | let function = overload_result.function; | |
| 1048 | if function.is_unsafe_constraints then | |
| 1049 | _logger.warn(location, "unchecked-constraints", "call to {function} has unchecked constraints"); | |
| 1050 | fi | |
| 1051 | ||
| 1052 | let arguments = Collections.LIST[Value](); | |
| 1053 | arguments.add(null_check); | |
| 1054 | arguments.add(member_check); | |
| 1055 | ||
| 1056 | return function.call( | |
| 1057 | location, | |
| 1058 | null, | |
| 1059 | arguments, | |
| 1060 | bool_type, | |
| 1061 | _function_caller | |
| 1062 | ); | |
| 1063 | fi | |
| 1064 | fi | |
| 1065 | fi | |
| 1066 | ||
| 1067 | return null_check; | |
| 1068 | si | |
| 1069 | ||
| 1070 | // For a `?` / `!` operand, identify the default variant to | |
| 1071 | // dispatch against. Returns the union's `default_variant` | |
| 1072 | // when the operand is the union (null when the union has | |
| 1073 | // no default — a source union without one, or an older | |
| 1074 | // cross-asm union compiled before the | |
| 1075 | // `DEFAULT_VARIANT_ATTRIBUTE` marker existed); returns the | |
| 1076 | // variant itself when the operand is already narrowed to | |
| 1077 | // its parent union's default variant so the caller can | |
| 1078 | // skip an extra cast. Null for any other shape — the | |
| 1079 | // caller's branch then short-circuits `?` to a bare null | |
| 1080 | // check and `!` to a non-null assert on the operand. | |
| 1081 | _get_default_variant_for_operand( | |
| 1082 | classy: Semantic.Symbols.Classy? | |
| 1083 | ) -> Semantic.Symbols.VARIANT? is | |
| 1084 | if !classy? then | |
| 1085 | return null; | |
| 1086 | fi | |
| 1087 | ||
| 1088 | if classy.is_union then | |
| 1089 | let union_classy = cast Semantic.Symbols.UNION?(classy)!; | |
| 1090 | return union_classy.default_variant; | |
| 1091 | fi | |
| 1092 | ||
| 1093 | if classy.is_variant then | |
| 1094 | let variant_classy = cast Semantic.Symbols.VARIANT?(classy)!; | |
| 1095 | ||
| 1096 | if !variant_classy.owner? \/ !isa Semantic.Symbols.UNION(variant_classy.owner) then | |
| 1097 | return null; | |
| 1098 | fi | |
| 1099 | ||
| 1100 | let owner_union = cast Semantic.Symbols.UNION(variant_classy.owner); | |
| 1101 | ||
| 1102 | if owner_union.default_variant == variant_classy then | |
| 1103 | return variant_classy; | |
| 1104 | fi | |
| 1105 | fi | |
| 1106 | ||
| 1107 | return null; | |
| 1108 | si | |
| 1109 | ||
| 1110 | // `u?` lowers to `isa Default(u)`. The receiver's type | |
| 1111 | // (often a generic instantiation of the union) drives | |
| 1112 | // specialisation of the variant target type so the emitted | |
| 1113 | // `isinst` references a loadable closed-generic class. | |
| 1114 | _build_default_variant_isa( | |
| 1115 | location: LOCATION, | |
| 1116 | operand: Value, | |
| 1117 | default_variant: Semantic.Symbols.VARIANT, | |
| 1118 | bool_type: Type | |
| 1119 | ) -> Value is | |
| 1120 | let variant_type = | |
| 1121 | _condition_analyzer.try_get_variant_type_for_classy( | |
| 1122 | operand.type!, | |
| 1123 | default_variant | |
| 1124 | ); | |
| 1125 | ||
| 1126 | if !variant_type? then | |
| 1127 | return DUMMY(bool_type, location); | |
| 1128 | fi | |
| 1129 | ||
| 1130 | return IR.Values.ISA(bool_type, variant_type, operand); | |
| 1131 | si | |
| 1132 | ||
| 1133 | // `u!` lowers to `cast Default(u)`, with single-field | |
| 1134 | // projection so the existing rule "default variant with one | |
| 1135 | // field unwraps to that field" rides on the new lowering. | |
| 1136 | // When the operand is already narrowed to the default | |
| 1137 | // variant the cast is elided — the CLR accepts loading the | |
| 1138 | // field directly off the variant-shaped receiver. | |
| 1139 | _build_default_variant_unwrap( | |
| 1140 | location: LOCATION, | |
| 1141 | operand: Value, | |
| 1142 | classy: Semantic.Symbols.Classy, | |
| 1143 | default_variant: Semantic.Symbols.VARIANT | |
| 1144 | ) -> Value is | |
| 1145 | let variant_type = | |
| 1146 | _condition_analyzer.try_get_variant_type_for_classy( | |
| 1147 | operand.type!, | |
| 1148 | default_variant | |
| 1149 | ); | |
| 1150 | ||
| 1151 | if !variant_type? then | |
| 1152 | return DUMMY(Semantic.Types.ERROR(), location); | |
| 1153 | fi | |
| 1154 | ||
| 1155 | let variant_value: Value mut = operand; | |
| 1156 | ||
| 1157 | if !classy.is_variant then | |
| 1158 | variant_value = IR.Values.CAST(variant_type, operand); | |
| 1159 | fi | |
| 1160 | ||
| 1161 | // Single-field unwrap rides on the cast: a default | |
| 1162 | // variant declaring exactly one field — own or inherited | |
| 1163 | // from the union's primary header — projects to that | |
| 1164 | // field. Multi-field defaults return the variant itself | |
| 1165 | // so callers can read every field via member access. | |
| 1166 | if default_variant.field_count == 1 then | |
| 1167 | let field_name = default_variant.get_destructure_member_name(0); | |
| 1168 | ||
| 1169 | if field_name? then | |
| 1170 | let field_member = variant_type.find_member(field_name); | |
| 1171 | ||
| 1172 | if field_member? then | |
| 1173 | return field_member.load(location, variant_value, _symbol_loader); | |
| 1174 | fi | |
| 1175 | fi | |
| 1176 | fi | |
| 1177 | ||
| 1178 | return variant_value; | |
| 1179 | si | |
| 1180 | ||
| 1181 | // Build a hinted "narrow further" message when a member | |
| 1182 | // access on a ONE_OF fails to find the member on the root | |
| 1183 | // but every in-set subtype has a same-named member. Returns | |
| 1184 | // null when the hint doesn't apply (receiver isn't a ONE_OF, | |
| 1185 | // or the name is missing on at least one in-set subtype). | |
| 1186 | // Subtype-private fields can't be accessed through ONE_OF | |
| 1187 | // without IL-side subtype-dispatching support — for now we | |
| 1188 | // just direct the user to narrow further. Applies uniformly | |
| 1189 | // to a union's variants and a closed class's subclasses. | |
| 1190 | try_describe_intersection_miss( | |
| 1191 | receiver_type: Type, | |
| 1192 | member_name: string | |
| 1193 | ) -> string? is | |
| 1194 | if !isa Semantic.Types.ONE_OF(receiver_type) then | |
| 1195 | return null; | |
| 1196 | fi | |
| 1197 | ||
| 1198 | let one_of = receiver_type; | |
| 1199 | ||
| 1200 | let any_subtype mut = false; | |
| 1201 | for subtype in one_of.subtypes do | |
| 1202 | if !subtype.find_member(member_name)? then | |
| 1203 | return null; | |
| 1204 | fi | |
| 1205 | any_subtype = true; | |
| 1206 | od | |
| 1207 | ||
| 1208 | if !any_subtype then | |
| 1209 | return null; | |
| 1210 | fi | |
| 1211 | ||
| 1212 | let names = System.Text.StringBuilder(); | |
| 1213 | let seen_any mut = false; | |
| 1214 | for subtype in one_of.subtypes do | |
| 1215 | if seen_any then | |
| 1216 | names.append(" | "); | |
| 1217 | fi | |
| 1218 | names.append(subtype.name); | |
| 1219 | seen_any = true; | |
| 1220 | od | |
| 1221 | ||
| 1222 | return "member {member_name} is ambiguous in {names}"; | |
| 1223 | si | |
| 1224 | ||
| 1225 | // Build the IR value for an `a?.b` access. Returns the | |
| 1226 | // COALESCE_LOAD wrap when the member is a readable field or | |
| 1227 | // property; returns null (so the caller falls back to a plain | |
| 1228 | // access) on shapes that aren't lowered here. Emits a | |
| 1229 | // diagnostic for each unsupported shape so the user learns | |
| 1230 | // why the `?.` had no effect. | |
| 1231 | _build_coalesce_load( | |
| 1232 | member: Trees.Expressions.MEMBER, | |
| 1233 | symbol: Semantic.Symbols.Symbol | |
| 1234 | ) -> Value? is | |
| 1235 | // A method selection is coalesced at the enclosing call - | |
| 1236 | // the whole call, argument evaluation included, must | |
| 1237 | // short-circuit on an absent receiver - so a function | |
| 1238 | // group falls through silently to the plain load the call | |
| 1239 | // path consumes. An uncalled method reference through | |
| 1240 | // `?.` then fails downstream exactly as it does through | |
| 1241 | // `.`. | |
| 1242 | if isa Semantic.Symbols.FUNCTION_GROUP(symbol) then | |
| 1243 | return null; | |
| 1244 | fi | |
| 1245 | ||
| 1246 | if | |
| 1247 | !isa Semantic.Symbols.Field(symbol) /\ | |
| 1248 | !isa Semantic.Symbols.Property(symbol) | |
| 1249 | then | |
| 1250 | _logger.error( | |
| 1251 | member.location, | |
| 1252 | "coalescing member access supports fields, properties and method calls only" | |
| 1253 | ); | |
| 1254 | return null; | |
| 1255 | fi | |
| 1256 | ||
| 1257 | return build_coalesce_wrap( | |
| 1258 | member, | |
| 1259 | symbol.is_instance, | |
| 1260 | from => symbol.load(member.location, from, _symbol_loader) | |
| 1261 | ); | |
| 1262 | si | |
| 1263 | ||
| 1264 | // Shared lowering for `a?.b` accesses and `a?.m(...)` calls: | |
| 1265 | // receiver presence diagnostics, unwrap of the optional | |
| 1266 | // receiver, optional widening of the result and the | |
| 1267 | // COALESCE_LOAD composition. `build_member_value` produces | |
| 1268 | // the member load or call against the supplied receiver | |
| 1269 | // stand-in: the original receiver value when it is statically | |
| 1270 | // present, or a STACK_TOP of the unwrapped receiver type | |
| 1271 | // inside the short-circuit arm. `receiver_consumed` is false | |
| 1272 | // when the member is static - the present arm then pops the | |
| 1273 | // tested receiver instead of feeding it to the member value. | |
| 1274 | // Returns null, with any diagnostic already emitted, when the | |
| 1275 | // shape can't be lowered. | |
| 1276 | build_coalesce_wrap( | |
| 1277 | member: Trees.Expressions.MEMBER, | |
| 1278 | receiver_consumed: bool, | |
| 1279 | build_member_value: (Value) -> Value? | |
| 1280 | ) -> Value? is | |
| 1281 | let receiver = member.left.value; | |
| 1282 | ||
| 1283 | if !receiver? \/ !receiver.type? then | |
| 1284 | return null; | |
| 1285 | fi | |
| 1286 | ||
| 1287 | let receiver_type = receiver.type!; | |
| 1288 | ||
| 1289 | // A non-optional receiver (declared so, or flow-narrowed | |
| 1290 | // from `T?` to `T`) is statically present, so the null | |
| 1291 | // test can never fail. One flow-narrowed from optional | |
| 1292 | // gets a redundancy warning; a never-optional value type | |
| 1293 | // is an error (a struct is never null, so the test has | |
| 1294 | // no defensive value); a never-optional reference stays | |
| 1295 | // legal with no diagnostic, as the null-defense idiom at | |
| 1296 | // unsound boundaries (reflected APIs, staged tree | |
| 1297 | // construction) where null can arrive despite the static | |
| 1298 | // type. The access is emitted directly — the conditional | |
| 1299 | // path is unsound for a value-type receiver (`dup; | |
| 1300 | // brfalse` rejects a struct on the stack) and unnecessary | |
| 1301 | // work for a reference receiver. The result is still | |
| 1302 | // widened to the optional shape the user asked for with | |
| 1303 | // `?.`. | |
| 1304 | if !receiver_type.is_optional then | |
| 1305 | let target = _visitor.try_get_narrowing_target(member.left); | |
| 1306 | let declared = if target? then _flow.declared_type_of(target) else null fi; | |
| 1307 | ||
| 1308 | if declared? /\ declared.is_optional then | |
| 1309 | _logger.warn( | |
| 1310 | member.location, | |
| 1311 | "redundant-coalesce", | |
| 1312 | "'?.' is redundant here" | |
| 1313 | ); | |
| 1314 | elif receiver_type.is_value_type then | |
| 1315 | _logger.error(member.left.location, "receiver is not optional"); | |
| 1316 | return null; | |
| 1317 | fi | |
| 1318 | ||
| 1319 | let direct = build_member_value(receiver); | |
| 1320 | ||
| 1321 | if !direct? then | |
| 1322 | return null; | |
| 1323 | fi | |
| 1324 | ||
| 1325 | return widen_coalesce_result(direct); | |
| 1326 | fi | |
| 1327 | ||
| 1328 | let receiver_is_value_optional = receiver_type.is_value_type; | |
| 1329 | ||
| 1330 | // The member symbol lives on the receiver's underlying | |
| 1331 | // type regardless of the `?` flag, so the member value is | |
| 1332 | // built against a STACK_TOP of the non-optional type and | |
| 1333 | // emits the expected access or call ops with no preceding | |
| 1334 | // receiver gen. | |
| 1335 | let inner_type = | |
| 1336 | if receiver_is_value_optional then | |
| 1337 | receiver_type.optional_inner_type; | |
| 1338 | else | |
| 1339 | receiver_type.as_non_optional(); | |
| 1340 | fi; | |
| 1341 | ||
| 1342 | if !inner_type? then | |
| 1343 | return null; | |
| 1344 | fi | |
| 1345 | ||
| 1346 | // STACK_TOP (has_address=false): the inner-receiver | |
| 1347 | // value is on the stack, not its address. A struct | |
| 1348 | // member access reads the value off the top, and the | |
| 1349 | // existing call_struct_method path's `ADDRESS(from)` | |
| 1350 | // spill takes its address as needed. A STACK_TOP_ADDRESS | |
| 1351 | // here would tell that spill the address is already | |
| 1352 | // present and skip it — producing a `call instance` on a | |
| 1353 | // bare value, which segfaults at the JIT. | |
| 1354 | let stack_top: IR.Values.Value = IR.Values.STACK_TOP(inner_type); | |
| 1355 | ||
| 1356 | let raw = build_member_value(stack_top); | |
| 1357 | ||
| 1358 | if !raw? then | |
| 1359 | return null; | |
| 1360 | fi | |
| 1361 | ||
| 1362 | let arm = _widen_coalesce_arm(raw); | |
| 1363 | ||
| 1364 | if !arm? then | |
| 1365 | return null; | |
| 1366 | fi | |
| 1367 | ||
| 1368 | if receiver_is_value_optional then | |
| 1369 | // Build presence test (get_has_value) and value | |
| 1370 | // extract (get_value) against a STACK_TOP_ADDRESS so | |
| 1371 | // both consume the address dup'd by COALESCE_LOAD. | |
| 1372 | let address_stand_in = IR.Values.STACK_TOP_ADDRESS(receiver_type); | |
| 1373 | let has_value_member = receiver_type.find_member("has_value"); | |
| 1374 | let value_member = receiver_type.find_member("value"); | |
| 1375 | ||
| 1376 | if !has_value_member? \/ !value_member? then | |
| 1377 | _logger.poison( | |
| 1378 | member.location, | |
| 1379 | "coalescing member access receiver {receiver_type} missing has_value or value member" | |
| 1380 | ); | |
| 1381 | return null; | |
| 1382 | fi | |
| 1383 | ||
| 1384 | let presence_test = has_value_member.load(member.location, address_stand_in, _symbol_loader); | |
| 1385 | ||
| 1386 | let value_extract = | |
| 1387 | if receiver_consumed then | |
| 1388 | value_member.load(member.location, address_stand_in, _symbol_loader) | |
| 1389 | else | |
| 1390 | null | |
| 1391 | fi; | |
| 1392 | ||
| 1393 | return IR.Values.COALESCE_LOAD( | |
| 1394 | receiver, | |
| 1395 | presence_test, | |
| 1396 | value_extract, | |
| 1397 | arm.member_value, | |
| 1398 | arm.null_value, | |
| 1399 | arm.result_type, | |
| 1400 | receiver_consumed | |
| 1401 | ); | |
| 1402 | fi | |
| 1403 | ||
| 1404 | return IR.Values.COALESCE_LOAD(receiver, arm.member_value, arm.null_value, arm.result_type, receiver_consumed); | |
| 1405 | si | |
| 1406 | ||
| 1407 | // Re-seat a coalescing member access whose loaded member is | |
| 1408 | // itself then invoked - `a?.f(...)` where f is a | |
| 1409 | // function-typed field or property. The invocation must sit | |
| 1410 | // inside the short-circuit arm, so the original wrap's | |
| 1411 | // receiver plumbing is reused around the call value, which | |
| 1412 | // consumes the original member load from the same arm. | |
| 1413 | rewrap_coalesce_call( | |
| 1414 | original: IR.Values.COALESCE_LOAD, | |
| 1415 | call_value: Value | |
| 1416 | ) -> Value? is | |
| 1417 | let arm = _widen_coalesce_arm(call_value); | |
| 1418 | ||
| 1419 | if !arm? then | |
| 1420 | return null; | |
| 1421 | fi | |
| 1422 | ||
| 1423 | if original.receiver_is_value_type then | |
| 1424 | return IR.Values.COALESCE_LOAD( | |
| 1425 | original.receiver, | |
| 1426 | original.presence_test!, | |
| 1427 | original.value_extract, | |
| 1428 | arm.member_value, | |
| 1429 | arm.null_value, | |
| 1430 | arm.result_type, | |
| 1431 | true | |
| 1432 | ); | |
| 1433 | fi | |
| 1434 | ||
| 1435 | return IR.Values.COALESCE_LOAD( | |
| 1436 | original.receiver, | |
| 1437 | arm.member_value, | |
| 1438 | arm.null_value, | |
| 1439 | arm.result_type, | |
| 1440 | true | |
| 1441 | ); | |
| 1442 | si | |
| 1443 | ||
| 1444 | // The direct result of a coalescing access or call whose | |
| 1445 | // receiver is statically present, widened to the optional | |
| 1446 | // shape the `?.` asked for. A void result stays void. | |
| 1447 | widen_coalesce_result(direct: Value) -> Value? is | |
| 1448 | let direct_type = direct.type; | |
| 1449 | ||
| 1450 | if !direct_type? then | |
| 1451 | return null; | |
| 1452 | fi | |
| 1453 | ||
| 1454 | if direct_type.is_void then | |
| 1455 | return direct; | |
| 1456 | fi | |
| 1457 | ||
| 1458 | let direct_result = build_optional_type(direct_type, _innate_symbol_lookup); | |
| 1459 | ||
| 1460 | if !direct_type.is_optional /\ direct_result.is_value_type then | |
| 1461 | return IR.Values.WRAP_OPTIONAL(direct_result, direct); | |
| 1462 | fi | |
| 1463 | ||
| 1464 | // Reference T and T? share IL — re-type the load. | |
| 1465 | if !direct_type.matches(direct_result) then | |
| 1466 | return IR.Values.TYPE_WRAPPER(direct_result, direct); | |
| 1467 | fi | |
| 1468 | ||
| 1469 | return direct; | |
| 1470 | si | |
| 1471 | ||
| 1472 | // Widen a present-arm member value to the optional result | |
| 1473 | // shape of the enclosing `?.`: | |
| 1474 | // - void → no widening, no null sentinel. | |
| 1475 | // - reference T → T flagged optional, IL identity. | |
| 1476 | // - value T → NULLABLE[T] via WRAP_OPTIONAL (newobj | |
| 1477 | // Nullable<T>::.ctor(T)). | |
| 1478 | // - already-optional U → identity. | |
| 1479 | _widen_coalesce_arm(raw: Value) -> COALESCE_ARM? is | |
| 1480 | let raw_type = raw.type; | |
| 1481 | ||
| 1482 | if !raw_type? then | |
| 1483 | return null; | |
| 1484 | fi | |
| 1485 | ||
| 1486 | if raw_type.is_void then | |
| 1487 | return COALESCE_ARM(raw, null, raw_type); | |
| 1488 | fi | |
| 1489 | ||
| 1490 | let result_type = build_optional_type(raw_type, _innate_symbol_lookup); | |
| 1491 | ||
| 1492 | let member_value: Value = | |
| 1493 | if !raw_type.is_optional /\ result_type.is_value_type then | |
| 1494 | IR.Values.WRAP_OPTIONAL(result_type, raw) | |
| 1495 | else | |
| 1496 | raw | |
| 1497 | fi; | |
| 1498 | ||
| 1499 | let null_value = _build_null_sentinel(result_type); | |
| 1500 | ||
| 1501 | if !null_value? then | |
| 1502 | return null; | |
| 1503 | fi | |
| 1504 | ||
| 1505 | return COALESCE_ARM(member_value, null_value, result_type); | |
| 1506 | si | |
| 1507 | ||
| 1508 | // The null-arm sentinel for a coalescing access of result | |
| 1509 | // type `result_type`: `ldnull` for a reference type, a fresh | |
| 1510 | // DEFAULT (which hoists a `.locals init` and pushes the zero | |
| 1511 | // value) for a value-type optional like NULLABLE[T] or | |
| 1512 | // MAYBE[T]. | |
| 1513 | _build_null_sentinel(result_type: Type?) -> Value? is | |
| 1514 | if !result_type? then | |
| 1515 | return null; | |
| 1516 | fi | |
| 1517 | ||
| 1518 | if result_type.is_value_type then | |
| 1519 | return IR.Values.DEFAULT(result_type); | |
| 1520 | fi | |
| 1521 | ||
| 1522 | return IR.RAW(result_type, "ldnull"); | |
| 1523 | si | |
| 1524 | ||
| 1525 | // The `T?` form of `t`: NULLABLE[T] for a value type, the | |
| 1526 | // flagged reference for a reference type. `as_optional()` | |
| 1527 | // alone returns the receiver for a value type — leaving the | |
| 1528 | // result mistyped as `T` — so this dispatches the way | |
| 1529 | // `resolve_type_expressions` does for a written `T?`. Static | |
| 1530 | // so the rule can be pinned without standing up a full | |
| 1531 | // COMPILE_ACCESS instance. | |
| 1532 | build_optional_type(t: Type, lookup: Semantic.Lookups.InnateSymbolLookup) -> Type static is | |
| 1533 | // t may be null | |
| 1534 | @suppress("presence-test-non-optional") | |
| 1535 | if !t? then | |
| 1536 | return t; | |
| 1537 | fi | |
| 1538 | ||
| 1539 | if t.is_optional then | |
| 1540 | return t; | |
| 1541 | fi | |
| 1542 | ||
| 1543 | if t.is_value_type then | |
| 1544 | return lookup.get_optional_type(t); | |
| 1545 | fi | |
| 1546 | ||
| 1547 | return t.as_optional(); | |
| 1548 | si | |
| 1549 | si | |
| 1550 | ||
| 1551 | // The present-arm pieces of a coalescing wrap: the member value | |
| 1552 | // widened to the optional result shape, the null-arm sentinel | |
| 1553 | // (absent when the member value is void) and the result type. | |
| 1554 | class COALESCE_ARM( | |
| 1555 | member_value: Value, | |
| 1556 | null_value: Value?, | |
| 1557 | result_type: Type | |
| 1558 | ) is | |
| 1559 | si | |
| 1560 | si |