Files
ww/selfhost/cmd/wcc/check.ww
Hojun-Cho d68d3c7eb4 lib: extract rt module from os, sweep imports
Hare puts runtime allocation in rt::, not os:: (ref/hare/rt/malloc.ha:27,
README). ww's `@symbol("rt_alloc") fn alloc(n: u64) *void;` lived at
lib/os/os.ww as a historical bootstrap shortcut; this commit relocates
it to a new lib/rt/malloc.ww and sweeps every site that depended on
`import os` for the alloc decl over to `import rt`.

This is commit 1 of 3 in the lib/rt extraction (#35):
  1. (this) move decl, sweep imports — preserves shape
  2. rename rt_alloc → rt_malloc (#38)
  3. nullable return type + OOM-propagating builtin lowering (#39)

No rename here. Symbol stays rt_alloc, function stays `alloc`, return
stays *void. Behavior identical — same ffi resolution outcome, just
sourced from a different module file. The rt::ensure runtime helper at
selfhost/rt/ensure.ww is its own compilation unit with a local decl and
is untouched.

Side effect: every wcc cgen file used `rt` as a local *node variable
name for "return type." `import rt;` shadows the module, so each
selfhost/cmd/wcc/{check,cgenstmt,cgenexpr,cgenutil}.ww site renamed
to `rtyp`. Mechanical follow-through; only the wcc module-import was
forced to do this rename.

Verified 132/132 + 995_self_rebuild byte-identity (5 wwstage tools
round-trip byte-identical).
2026-05-20 20:39:52 +09:00

2122 lines
75 KiB
Plaintext

// selfhost/cmd/wcc/check.ww — minimal port of cmd/wcc/check.c.
//
// Status: name-resolution + primitive-type seeding only. Full type
// inference, conversion rules, tagged-union dispatch typing, return-
// type checking, etc. all live in cmd/wcc/check.c (937 lines) and
// will land here in subsequent commits.
//
// What this version does:
// 1. Creates a top scope and seeds it with primitive type names so
// `i32`, `str`, `*u8` etc. resolve.
// 2. Walks the file's top-level decls (use/def/type/fn/let) and
// installs Sym entries for each.
// 3. Recursively walks fn bodies; for every nkind.N_IDENT used as an
// expression or as a type name, looks it up and counts the
// resolved vs. unresolved.
// 4. Returns a summary the caller (wwdump -r) prints; the test
// asserts unresolved == 0 on every selfhost fixture, which is
// the floor signal that the frontend can name-resolve real ww.
package wcc;
import os;
import mem;
import tok;
type checker = struct {
a: *arena,
tc: *tctx,
top: *scope,
cur: *scope,
nresolved: i32,
nunresolved: i32,
errs: i32,
verbose: i32, // when non-zero, log each unresolved name
fnret: *node, // enclosing fn's return type AST (for `?`)
curmod: str, // importing-module bareword for the decl
// currently being walked; "" for primary
// compilation unit. Drives same-module
// preference in bare-leaf lookups.
file: *node, // N_FILE root; used by checkmoduleshadow
// to consult the declaring source's own
// `use` directives.
};
// seedprimitives — install the built-in type names so `i32`, `str`,
// etc. can be looked up like ordinary symbols.
fn seedprimitives(c: *checker) void = {
scopedefine(c.top, "void", skind.SK_TYPE, c.tc.tyvoid, nil);
scopedefine(c.top, "bool", skind.SK_TYPE, c.tc.tybool, nil);
scopedefine(c.top, "rune", skind.SK_TYPE, c.tc.tyrune, nil);
scopedefine(c.top, "i8", skind.SK_TYPE, c.tc.tyi8, nil);
scopedefine(c.top, "i16", skind.SK_TYPE, c.tc.tyi16, nil);
scopedefine(c.top, "i32", skind.SK_TYPE, c.tc.tyi32, nil);
scopedefine(c.top, "i64", skind.SK_TYPE, c.tc.tyi64, nil);
scopedefine(c.top, "u8", skind.SK_TYPE, c.tc.tyu8, nil);
scopedefine(c.top, "u16", skind.SK_TYPE, c.tc.tyu16, nil);
scopedefine(c.top, "u32", skind.SK_TYPE, c.tc.tyu32, nil);
scopedefine(c.top, "u64", skind.SK_TYPE, c.tc.tyu64, nil);
scopedefine(c.top, "int", skind.SK_TYPE, c.tc.tyint, nil);
scopedefine(c.top, "uint", skind.SK_TYPE, c.tc.tyuint, nil);
scopedefine(c.top, "uintptr", skind.SK_TYPE, c.tc.tyuintptr, nil);
scopedefine(c.top, "f32", skind.SK_TYPE, c.tc.tyf32, nil);
scopedefine(c.top, "f64", skind.SK_TYPE, c.tc.tyf64, nil);
scopedefine(c.top, "str", skind.SK_TYPE, c.tc.tystr, nil);
scopedefine(c.top, "never", skind.SK_TYPE, c.tc.tynever, nil);
// #29: predeclare `type nomem = !void;` so user code needn't
// declare it locally. Synthesize an nkind.N_TYPEDECL whose lhs is
// nkind.N_TBANG{nkind.N_TNAME("void")} so varianterr and other
// iserror-aware paths treat `nomem` identically to a user-written
// alias. Mirrors cmd/wcc/check.c lookup_builtin returning
// ty_nomem (NAMED, under=ty_void, iserror=1). Note: cgen owns a
// separate alias chain — see collectaliases in cgen.ww for the
// companion seed.
let empty: str;
let tnvoid: *node = newnode(c.a, nkind.N_TNAME, empty, 0, 0);
tnvoid.str = "void";
let bang: *node = newnode(c.a, nkind.N_TBANG, empty, 0, 0);
bang.lhs = tnvoid;
let nomemdecl: *node = newnode(c.a, nkind.N_TYPEDECL, empty, 0, 0);
nomemdecl.str = "nomem";
nomemdecl.lhs = bang;
scopedefine(c.top, "nomem", skind.SK_TYPE, nil, nomemdecl);
// `nil`, `true`, `false` are keywords — handled at the lex/parser
// level, no symbol needed.
// `len`, `alloc`, `free`, `append` are pseudo-builtins; scopedefine
// them so their use sites resolve. The actual semantics live in cgen.
scopedefine(c.top, "len", skind.SK_FN, nil, nil);
scopedefine(c.top, "alloc", skind.SK_FN, nil, nil);
scopedefine(c.top, "free", skind.SK_FN, nil, nil);
scopedefine(c.top, "append", skind.SK_FN, nil, nil);
// #42: typed builtins folded to integer literals at check time —
// `size(T)` / `align(T)` (arg is a type-expression planted by the
// parser at lib/ww/parse/expr.ww:254-267) and `offset(e.f)` (arg is
// an N_DOT). exprtype intercepts these and rewrites the N_CALL to
// N_INTLIT so cgen never sees an unresolved size/align/offset symbol.
// Mirrors cmd/wcc/check.c:907-955.
scopedefine(c.top, "size", skind.SK_FN, nil, nil);
scopedefine(c.top, "align", skind.SK_FN, nil, nil);
scopedefine(c.top, "offset", skind.SK_FN, nil, nil);
};
// declmod — module-tag stamp for a top-level decl.
//
// The driver concatenates imported sources before the primary file and
// emits `// MODULE: foo` directives the lexer pins onto each decl's
// `module` field. We treat a decl as "imported" iff its module
// directive matches some `use IDENT;` bareword in this compilation
// unit. Primary-file decls return "" so they coexist (mod="") with
// imported decls of the same leaf name in scopelookupinmodule.
fn declmod(file: *node, d: *node) str = {
let empty: str;
if (d == nil) { return empty; };
if (d.nmod.len == 0) { return empty; };
if (file == nil) { return empty; };
let u: *node = file.list;
for (u != nil) {
if (u.kind == nkind.N_USE) {
if (streq(u.str, d.nmod)) { return d.nmod; };
};
u = u.next;
};
return empty;
};
// srcimports — does the source file that contributed decl-module
// `modtag` carry `use <name>;`? Mirrors cstage's src_imports —
// `modtag.len == 0` means primary, matching declmod's empty-str
// return for primary-source decls.
fn srcimports(file: *node, modtag: str, name: str) bool = {
if (file == nil) { return false; };
if (name.len == 0) { return false; };
let u: *node = file.list;
for (u != nil) {
if (u.kind == nkind.N_USE) {
// Skip self-imports: lib/fmt/fmttest.ww carries
// `use fmt;` while its module tag is also "fmt".
// That directive doesn't introduce a foreign
// module bareword and lib/fmt's own
// `fn bsprintf(fmt: str, ...)` is not a shadow.
if (u.nmod.len > 0) {
if (streq(u.nmod, u.str)) {
u = u.next;
continue;
};
};
let um: str = declmod(file, u);
let m: bool = false;
if (modtag.len == 0) {
if (um.len == 0) { m = true; };
} else { if (streq(um, modtag)) { m = true; }; };
if (m) {
if (streq(u.str, name)) { return true; };
};
};
u = u.next;
};
return false;
};
// checkmoduleshadow — enforce "value names and module names are
// disjoint" at nested-scope binds. Mirrors cstage check_module_shadow
// (cmd/wcc/check.c). Fires for fn params / lets / forrange iters /
// mcase bindings whose name matches an in-scope `use foo;` import
// declared in the same source file. Top-level decls are exempt
// (their same-leaf-as-module pattern is the intentional coexistence
// shape — `use fnmatch; fn fnmatch(...)` etc.).
fn checkmoduleshadow(c: *checker, name: str, kindstr: str) void = {
if (name.len == 0) { return; };
if (c.cur == c.top) { return; };
let seen: bool = false;
let s: *scope = c.cur;
for (s != nil) {
let r: *sym = scopelookuplocal(s, name);
if (r != nil) {
if (r.skind == skind.SK_USE) {
seen = true;
s = nil;
};
};
if (s != nil) { s = s.parent; };
};
if (!seen) { return; };
if (!srcimports(c.file, c.curmod, name)) { return; };
os.write(2, kindstr.ptr, kindstr.len: u64);
os.write(2, " '".ptr, 2u64);
os.write(2, name.ptr, name.len: u64);
os.write(2, "' shadows imported module '".ptr, 27u64);
os.write(2, name.ptr, name.len: u64);
os.write(2, "'\n".ptr, 2u64);
c.errs += 1;
};
// installdecl — install the top-level decl's name into the top scope.
// We don't compute its type yet (that's the resolve pass) — just bind
// the name so forward references resolve.
//
// Architectural note: wwstage uses COEXISTENCE rather than the cstage
// promote-SK_USE-in-place approach in cmd/wcc/check.c. SK_USE and any
// same-leaf SK_TYPE/SK_FN/SK_DEF/SK_VAR live as separate entries in
// the same scope-bucket, distinguished by `sym.mod`. The dot-prefix
// lookup in resolvewalk + scopelookupinmodule's mod-filter already
// disambiguate `fnmatch.flag` against an `fn fnmatch(...)` of the same
// leaf — no `use_alias` flag needed. So the cstage L1722-class bug
// (promotion missing use_alias) is structurally non-reachable here.
// Don't port the use_alias flag from cstage without first re-reading
// the architecture: adding a field to `sym` changes its size and risks
// the wwstage cgen amalloc-undersize trap (rob-pike). #11 (wwstage
// checkfile pass) will reconsider this when wwstage grows a real check
// pass on the cgen path.
// TODO(#11): cstage check.c errors on duplicate top-level type/def/fn
// (see cmd/wcc/check.c L1800/L1839/L1860 "duplicate <kind>") and on
// duplicate top-level let (cmd/wcc/check.c L1880, "duplicate let %s")
// once #32 lands. Wwstage's installdecl just drops the second insert
// silently. Add `if (s == nil) err(...)` here once #11 wires checkfile
// into w6c_ww. Silent-accept matches the deferred-check design — see
// test/wcc/708 and test/wcc/696 for the same cstage-only neg-case
// precedent.
fn installdecl(c: *checker, file: *node, d: *node) void = {
if (d == nil) { return; };
let k: nkind = d.kind;
let nm: str = d.str;
let mod: str = declmod(file, d);
if (k == nkind.N_USE) { scopedefine(c.top, nm, skind.SK_USE, nil, d); return; };
if (k == nkind.N_DEF) { scopedefineinmodule(c.top, nm, mod, skind.SK_DEF, nil, d); return; };
if (k == nkind.N_TYPEDECL) { scopedefineinmodule(c.top, nm, mod, skind.SK_TYPE, nil, d); return; };
if (k == nkind.N_FNDECL) { scopedefineinmodule(c.top, nm, mod, skind.SK_FN, nil, d); return; };
if (k == nkind.N_LET) { scopedefineinmodule(c.top, nm, mod, skind.SK_VAR, nil, d); return; };
};
// resolvewalk — recursive AST walk that, for every nkind.N_IDENT and
// nkind.N_TNAME seen, looks up the name and bumps the resolved/unresolved
// counters. Local lets are installed in the current scope as soon as
// their init/type expressions have been walked (forward use of a let
// before its declaration would resolve to nothing — same semantics as
// the C checker's collect-then-resolve flow within a function).
// Also runs the typed checks (match exhaustiveness, ? subset) in
// the same pass — they need the same scope state.
fn resolvewalk(c: *checker, n: *node) void = {
if (n == nil) { return; };
let k: nkind = n.kind;
// Typed checks fire on the way down so the scrutinee/operand
// is examined before the arm bodies install new bindings.
if (k == nkind.N_MATCH) { checkmatchexhaust(c, n); };
if (k == nkind.N_TRYPROP) { checktryprop(c, n); };
if (k == nkind.N_TYPETEST) { checkisas(c, n); };
if (k == nkind.N_TYPEASSERT) { checkisas(c, n); };
if (k == nkind.N_LET) { checkletassign(c, n); };
if (k == nkind.N_RETURN) { checkretassign(c, n); };
// `use IDENT;` — name is a module label, not a free ident.
if (k == nkind.N_USE) { return; };
if (k == nkind.N_IDENT) {
let nm: str = n.str;
if (nm.len > 0) {
let s: *sym = scopelookupprefer(c.cur, c.curmod, nm);
if (s == nil) {
c.nunresolved += 1;
if (c.verbose != 0) {
os.write(2, " unresolved id: ".ptr, 17u64);
os.write(2, nm.ptr, nm.len: u64);
os.write(2, "\n".ptr, 1u64);
};
} else { c.nresolved += 1; };
};
};
if (k == nkind.N_TNAME) {
let nm: str = n.str;
if (nm.len > 0) {
let s: *sym = scopelookupprefer(c.cur, c.curmod, nm);
// `pkg.Type` — strip the last dot prefix and look up
// the leaf with a mod filter so same-leaf-name types
// from different imports (`bufio.stream` vs
// `io.stream`) disambiguate to the right one.
// Mirrors cmd/wcc/check.c resolve_typename.
if (s == nil) {
let dot: i32 = nm.len - 1;
for (dot >= 0) {
if (nm[dot] == 46u8) { break; };
dot -= 1;
};
if (dot > 0) {
let head: str;
head.ptr = nm.ptr;
head.len = dot;
let m: *sym = scopelookup(c.cur, head);
if (m != nil) {
let leaf: str;
leaf.ptr = nm.ptr + (dot + 1): u64;
leaf.len = nm.len - (dot + 1);
s = scopelookupinmodule(c.cur, head, leaf);
};
};
};
if (s == nil) {
c.nunresolved += 1;
if (c.verbose != 0) {
os.write(2, " unresolved tname: ".ptr, 20u64);
os.write(2, nm.ptr, nm.len: u64);
os.write(2, "\n".ptr, 1u64);
};
} else { c.nresolved += 1; };
};
};
// `for (let x .. slice) body` / `for (let (a, b) .. slice) body` —
// each binding name becomes a fresh local. Walk the slice expr first
// so its idents resolve before the bindings shadow anything, then
// install bindings and walk the body/else.
//
// TODO(#11): cstage check.c (post-#32) errors `binding '%s'
// redeclared in same scope` when the tuple-pattern lists the same
// name twice (`for (let (a, a) .. xs)`). Wwstage's resolvewalk has
// no per-block scope (see resolvefnbody's docstring) and is used
// only by wwdump_ww as a diagnostic, so silent-accept here avoids
// false-positives on legal cross-block shadow until #11 adds the
// scoping infrastructure.
if (k == nkind.N_FORRANGE) {
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
if (n.list != nil) {
let m: *node = n.list;
for (m != nil) {
let bnm: str = m.str;
if (bnm.len > 0) {
checkmoduleshadow(c, bnm, "binding");
scopedefine(c.cur, bnm, skind.SK_VAR, nil, m);
};
m = m.next;
};
} else {
let bnm: str = n.str;
if (bnm.len > 0) {
checkmoduleshadow(c, bnm, "binding");
scopedefine(c.cur, bnm, skind.SK_VAR, nil, n);
};
};
if (n.body != nil) { resolvewalk(c, n.body); };
if (n.els != nil) { resolvewalk(c, n.els); };
return;
};
// `match (e) { case let v: T => stmt; ... }` — the binding `v`
// is declared by the case arm and visible inside its body. Push a
// fresh scope so `case let e: str` doesn't collide with an outer
// `let e: *T` (scopedefine drops same-scope dupes silently and
// would leave references to `e` resolving to the outer type).
// Mirrors cmd/wcc/check.c's newscope/saved-restore around cstmt.
if (k == nkind.N_MCASE) {
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
let outer: *scope = c.cur;
c.cur = newscope(c.a, outer);
let nm: str = n.str;
if (nm.len > 0) {
checkmoduleshadow(c, nm, "binding");
scopedefine(c.cur, nm, skind.SK_VAR, nil, n);
};
if (n.body != nil) { resolvewalk(c, n.body); };
c.cur = outer;
return;
};
// #53: lexical block. Push a child scope so locals introduced by
// inner-block lets (and the `let` install at the tail of this fn) go
// out of scope at block exit. Without this, a deeply nested
// `let i: u64 = 0u64;` survived to shadow a same-named outer
// `let i: i32 = 1;` for the whole fn body, and exprtype handed
// stale primitive types to checkletassign — silent miscompile
// becomes a false-positive on the next driver (`wwdump_ww -r`
// flagged the u64→i32 pair in selfhost/cmd/ww/enumeratedir).
// Mirrors cstage cstmt N_BLOCK at cmd/wcc/check.c:1559-1566.
if (k == nkind.N_BLOCK) {
let outer: *scope = c.cur;
c.cur = newscope(c.a, outer);
let m: *node = n.list;
for (m != nil) {
resolvewalk(c, m);
m = m.next;
};
c.cur = outer;
return;
};
if (k == nkind.N_DOT) {
// Walk only the base; the .field name is a member, not a
// free identifier.
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
return;
};
if (k == nkind.N_FIELD) {
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
return;
};
if (k == nkind.N_TFIELD) {
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
return;
};
// Walk children (mirroring ast.ww's printer descent order).
if (n.attr != nil) { resolvewalk(c, n.attr); };
if (n.lhs != nil) { resolvewalk(c, n.lhs); };
if (n.rhs != nil) { resolvewalk(c, n.rhs); };
if (n.cond != nil) { resolvewalk(c, n.cond); };
if (n.body != nil) { resolvewalk(c, n.body); };
if (n.els != nil) { resolvewalk(c, n.els); };
if (n.list != nil) {
let m: *node = n.list;
for (m != nil) {
resolvewalk(c, m);
m = m.next;
};
};
// #61 audit §1.8 — A.2 population: stamp tinfo onto type-expression
// nodes once their children have been walked (sub-element TNAMEs
// are now in scope so resolvealias inside tinfofornode can follow
// user-defined aliases). Cgen's slotsize fast-path reads off
// n.type_; uncovered shapes fall through to the cstage-mirror
// walker until the next sub-commit graduates them.
if (k == nkind.N_TNAME || k == nkind.N_TPTR ||
k == nkind.N_TSLICE || k == nkind.N_TCHAN ||
k == nkind.N_TBANG || k == nkind.N_TARRAY ||
k == nkind.N_TFN || k == nkind.N_TSTRUCT ||
k == nkind.N_TTUPLE || k == nkind.N_TTAGGED ||
k == nkind.N_TENUM) {
if (n.type_ == nil) {
let ti: *tinfo = tinfofornode(c, n);
if (ti != nil) { n.type_ = ti: *void; };
};
};
// #42: trigger the size/align/offset fold here so the mutation
// fires regardless of context (if-conditions, expression statements,
// etc.) — wwstage's exprtype is otherwise called only from
// checkletassign / checkretassign / TRYPROP, and an unwrapped
// `if (size(str) != 16)` would otherwise leave the N_CALL alone
// and cgen would emit a stray `CALL size(SB)`. Mirrors cstage
// cstmt's recursive cexpr discipline.
if (k == nkind.N_CALL) {
if (n.lhs != nil) {
if (n.lhs.kind == nkind.N_IDENT) {
let nm: str = n.lhs.str;
if (streq(nm, "size") || streq(nm, "align") || streq(nm, "offset")) {
let _t: *node = exprtype(c, n);
};
};
};
};
// After walking children: a local `let X: T = init;` registers
// `X` so subsequent statements can resolve it. Top-level lets
// are installed in installdecl, so this duplicate install at
// the file scope just no-ops (scopedefine returns nil on dup).
//
// Cross-block `let a; { let a; };` no longer trips dup-silence
// since #53 added N_BLOCK push/pop above — the inner `a` lands in
// the inner block's scope. Same-scope dup `let a=1; let a=2;`
// still silent-accepts here; promoting that to an error stays
// queued behind #11 (test/wcc/708 + test/wcc/696 are the cstage-
// only neg-case precedent).
if (k == nkind.N_LET) {
let nm: str = n.str;
if (nm.len > 0) {
checkmoduleshadow(c, nm, "let");
scopedefine(c.cur, nm, skind.SK_VAR, nil, n);
};
};
};
// ---- type-level helpers (AST-level, no resolved tinfo) --------------
//
// The selfhost check operates on AST type expressions rather than
// resolved Type structs. These helpers mirror what cmd/wcc/check.c
// does with tinfo, but only on the subset of cases this checker
// needs to enforce: tagged-union exhaustiveness, ? subset
// propagation, and !-flag semantics.
// unwrapbang — strip an nkind.N_TBANG wrapper; leaves other nodes alone.
fn unwrapbang(n: *node) *node = {
if (n == nil) { return nil; };
if (n.kind == nkind.N_TBANG) { return n.lhs; };
return n;
};
// resolvealias — if n is an nkind.N_TNAME pointing at a typedecl, return
// the typedecl's body (possibly recursively). Pass-through for any
// other node. The chain stops once we hit a non-nkind.N_TNAME node or a
// name we can't resolve.
fn resolvealias(c: *checker, n: *node) *node = {
let cur: *node = n;
for (cur != nil) {
if (cur.kind != nkind.N_TNAME) { return cur; };
let nm: str = cur.str;
// #51: pkg.alias type refs land here as a single TNAME whose
// str is the joined form (lib/ww/parse/parse.ww:258-265 in
// parsetype). Split on the rightmost '.' and bind the leaf in
// the head module's scope. Mirrors cstage resolve_typename
// cmd/wcc/check.c:74-83 strrchr branch — without this the
// raw `os.oserror` lookup misses and checkisas false-positives
// every cross-module tagged scrutinee.
let dotidx: i32 = -1;
let i: i32 = 0;
for (i < nm.len) {
if (nm[i] == 46u8) { dotidx = i; };
i += 1;
};
let s: *sym = nil;
if (dotidx >= 0) {
let head: str;
head.ptr = nm.ptr;
head.len = dotidx;
let leaf: str;
leaf.ptr = nm.ptr + ((dotidx + 1): u64);
leaf.len = nm.len - dotidx - 1;
s = scopelookupinmodule(c.cur, head, leaf);
} else {
s = scopelookup(c.cur, nm);
// #61 A.5: bare TNAME that collides with an imported
// module bareword. Two shapes hit this:
// - `let l: lex;` where `lex` struct lives in
// `package lex;` (mod matches leaf).
// - `let t: tok;` where `tok` struct lives in
// `package lex;` (mod differs from leaf — tok.ww
// declares `package lex;`).
// scopelookup bucket-walks the flat scope and can land
// on the SK_USE entry first; without the fallback we'd
// return the unresolved TNAME and tinfofornode aborts on
// body == n. scopelookuptype walks the same bucket but
// filters on SK_TYPE so the struct entry surfaces
// regardless of its declaring package. Mirrors the
// bare-vs-qualified pattern from task #57.
if (s != nil) {
if (s.skind != skind.SK_TYPE) {
let sm: *sym = scopelookuptype(c.cur, nm);
if (sm != nil) { s = sm; };
};
};
};
if (s == nil) { return cur; };
if (s.skind != skind.SK_TYPE) { return cur; };
let body: *node = nil;
if (s.decl != nil) { body = s.decl.lhs; };
if (body == nil) { return cur; };
cur = unwrapbang(body);
};
return n;
};
// typeeqast — structural equality on AST type expressions, mod
// the `!` wrapper. Mirrors variant_match in cgen + check.c: NAMED
// types compare by string (the closest stand-in for pointer
// identity at the AST level); other nodes recurse by kind.
fn typeeqast(a: *node, b: *node) bool = {
let aa: *node = unwrapbang(a);
let bb: *node = unwrapbang(b);
if (aa == nil) { return bb == nil; };
if (bb == nil) { return false; };
if (aa.kind != bb.kind) { return false; };
let k: nkind = aa.kind;
if (k == nkind.N_TNAME) { return streq(aa.str, bb.str); };
if (k == nkind.N_TPTR) { return typeeqast(aa.lhs, bb.lhs); };
if (k == nkind.N_TSLICE){ return typeeqast(aa.lhs, bb.lhs); };
if (k == nkind.N_TCHAN) { return typeeqast(aa.lhs, bb.lhs); };
// Conservative: anything else (struct/fn/tagged/tuple/array)
// fails the cheap check. Selfhost code doesn't currently rely
// on equality at these shapes for the targeted checks.
return false;
};
// varianterr — does this variant carry the `!` mark? Either
// the variant itself is nkind.N_TBANG or it's an alias whose typedecl
// body is `!T`. Mirrors C check.c's iserror-after-NAMED rule.
fn varianterr(c: *checker, v: *node) bool = {
if (v == nil) { return false; };
if (v.kind == nkind.N_TBANG) { return true; };
if (v.kind == nkind.N_TNAME) {
let s: *sym = scopelookup(c.cur, v.str);
if (s != nil) {
if (s.skind == skind.SK_TYPE) {
if (s.decl != nil) {
if (s.decl.lhs != nil) {
if (s.decl.lhs.kind == nkind.N_TBANG) {
return true;
};
};
};
};
};
};
return false;
};
// taggedhaserr — true iff any variant of `n` (assumed
// nkind.N_TTAGGED) is `!`-marked. Picks the explicit-flag semantics over
// the legacy "first variant = success" rule.
fn taggedhaserr(c: *checker, n: *node) bool = {
let v: *node = n.list;
for (v != nil) {
if (varianterr(c, v)) { return true; };
v = v.next;
};
return false;
};
// iserrvariant — under flag-aware mode (any !-marked variant),
// returns true iff `v` is `!`-marked. Under legacy mode (no flags),
// returns true iff `v` is not the first variant of `tagged`.
fn iserrvariant(c: *checker, tagged: *node, v: *node) bool = {
if (taggedhaserr(c, tagged)) {
return varianterr(c, v);
};
// Legacy: first variant of the union is success.
if (tagged.list == v) { return false; };
return true;
};
// scruttype — resolve the type expression for a match's
// scrutinee. Handles nkind.N_IDENT (look up local/param's declared
// type) and nkind.N_DOT (module-qualified ref). Returns nil if we
// can't statically determine the type. Used by exhaustiveness.
fn scruttype(c: *checker, e: *node) *node = {
if (e == nil) { return nil; };
if (e.kind == nkind.N_IDENT) {
let s: *sym = scopelookup(c.cur, e.str);
if (s == nil) { return nil; };
if (s.decl == nil) { return nil; };
// For nkind.N_LET / nkind.N_PARAM: declared type is decl.lhs.
return s.decl.lhs;
};
// #51: `match (pkg.var)` / `pkg.var is T` — module-qualified ref.
// lhs is N_IDENT (module bareword), str is the leaf. Bind via
// scopelookupinmodule so the declared type carries the same
// shape resolvealias' dotted-name branch now consumes. Falls
// silently to nil when lhs is a value (struct-field access) —
// the rest of the lenient-check contract.
if (e.kind == nkind.N_DOT) {
if (e.lhs == nil) { return nil; };
if (e.lhs.kind != nkind.N_IDENT) { return nil; };
let s: *sym = scopelookupinmodule(c.cur, e.lhs.str, e.str);
if (s == nil) { return nil; };
if (s.decl == nil) { return nil; };
return s.decl.lhs;
};
return nil;
};
// mktname — fabricate an nkind.N_TNAME node with str = `nm`. Used by
// exprtype to return primitive type nodes for literal
// expressions. The arena keeps them around as long as the checker.
fn mktname(c: *checker, nm: str) *node = {
let n: *node = newnode(c.a, nkind.N_TNAME, "", 0, 0);
n.str = nm;
return n;
};
// #43: SSoT for primitive type byte sizes. astsize's N_TNAME-primitive
// arm and every wwstage cgen size walker (slotsize/fieldsize/letemit-
// size/elemsizeof/paramfieldsize) consult this table so a future
// ty_str.size bump (#1) lands in one place. Returns -1 for non-prim
// names; callers fall back to alias/struct/enum lookup. Cstage's
// equivalent SSoT is cmd/wcc/type.c:46-79 (ty_void/ty_bool/.../ty_str).
fn primtypesize(nm: str) i64 = {
if (streq(nm, "void")) { return 0i64; };
if (streq(nm, "bool")) { return 1i64; };
if (streq(nm, "i8") || streq(nm, "u8")) { return 1i64; };
if (streq(nm, "i16") || streq(nm, "u16")) { return 2i64; };
if (streq(nm, "i32") || streq(nm, "u32") || streq(nm, "f32") || streq(nm, "rune")) { return 4i64; };
if (streq(nm, "i64") || streq(nm, "u64") || streq(nm, "f64")) { return 8i64; };
if (streq(nm, "int") || streq(nm, "uint") || streq(nm, "uintptr")) { return 8i64; };
if (streq(nm, "str")) { return 16i64; }; // sizelint-ok: SSoT for ty_str primtype (#64)
return -1i64;
};
// #43: SSoT for slice header size (ptr+len+cap = 24B today). Mirrors
// cstage cmd/wcc/type.c:103 (ty_slice->size = 24). Bumping a slice's
// header layout in #34 touches only this constant.
fn tyslicesize() i64 = { return 24i64; }; // sizelint-ok: SSoT for ty_slice header (#64)
// #42: AST-level layout helpers for the size(T)/align(T)/offset(e.f)
// fold. Mirror cstage resolve_type's size/align computation
// (cmd/wcc/check.c:286-528) on AST nodes — wwstage check.ww never
// materialises tinfo for user types so the fold has to walk the AST
// directly. Struct layout follows cstage check.c:471-526 (align each
// field, max align for the whole record, round size up to alignment).
fn astalign(c: *checker, t: *node) i64 = {
if (t == nil) { return 1i64; };
let k: nkind = t.kind;
if (k == nkind.N_TBANG) { return astalign(c, t.lhs); };
if (k == nkind.N_TPTR) { return 8i64; };
if (k == nkind.N_TSLICE) { return 8i64; };
if (k == nkind.N_TCHAN) { return 8i64; };
if (k == nkind.N_TFN) { return 8i64; };
if (k == nkind.N_TARRAY) { return astalign(c, t.lhs); };
if (k == nkind.N_TTAGGED) { return 8i64; };
if (k == nkind.N_TTUPLE) {
let m: i64 = 1i64;
let p: *node = t.list;
for (p != nil) {
let pa: i64 = astalign(c, p);
if (pa > m) { m = pa; };
p = p.next;
};
return m;
};
if (k == nkind.N_TSTRUCT) {
let m: i64 = 1i64;
let f: *node = t.list;
for (f != nil) {
if (f.kind == nkind.N_TFIELD) {
let fa: i64 = astalign(c, f.lhs);
if (fa > m) { m = fa; };
};
f = f.next;
};
return m;
};
if (k == nkind.N_TENUM) {
if (t.lhs != nil) { return astalign(c, t.lhs); };
return 4i64;
};
if (k == nkind.N_TNAME) {
let nm: str = t.str;
if (streq(nm, "void") || streq(nm, "bool") || streq(nm, "i8") || streq(nm, "u8")) { return 1i64; };
if (streq(nm, "i16") || streq(nm, "u16")) { return 2i64; };
if (streq(nm, "i32") || streq(nm, "u32") || streq(nm, "f32") || streq(nm, "rune")) { return 4i64; };
if (streq(nm, "i64") || streq(nm, "u64") || streq(nm, "f64") || streq(nm, "int") || streq(nm, "uint") || streq(nm, "uintptr") || streq(nm, "str")) { return 8i64; };
let resolved: *node = resolvealias(c, t);
if (resolved != nil && resolved != t) {
return astalign(c, resolved);
};
};
return 1i64;
};
fn astsize(c: *checker, t: *node) i64 = {
if (t == nil) { return 0i64; };
let k: nkind = t.kind;
if (k == nkind.N_TBANG) { return astsize(c, t.lhs); };
if (k == nkind.N_TPTR) { return 8i64; };
if (k == nkind.N_TSLICE) { return tyslicesize(); };
if (k == nkind.N_TCHAN) { return 8i64; };
if (k == nkind.N_TFN) { return 8i64; };
if (k == nkind.N_TARRAY) {
let elen: i64 = 0i64;
if (t.rhs != nil) {
if (t.rhs.kind == nkind.N_INTLIT) { elen = t.rhs.uval: i64; };
};
return astsize(c, t.lhs) * elen;
};
if (k == nkind.N_TTUPLE) {
let total: i64 = 0i64;
let p: *node = t.list;
for (p != nil) {
total += astsize(c, p);
p = p.next;
};
return total;
};
if (k == nkind.N_TSTRUCT) {
let off: i64 = 0i64;
let maxal: i64 = 1i64;
let f: *node = t.list;
for (f != nil) {
if (f.kind == nkind.N_TFIELD) {
let fa: i64 = astalign(c, f.lhs);
if (fa > maxal) { maxal = fa; };
off = (off + fa - 1i64) & ~(fa - 1i64);
off += astsize(c, f.lhs);
};
f = f.next;
};
return (off + maxal - 1i64) & ~(maxal - 1i64);
};
if (k == nkind.N_TTAGGED) {
// 8 (tag) + max variant payload, rounded up to 8.
let maxsz: i64 = 0i64;
let v: *node = t.list;
for (v != nil) {
let sz: i64 = astsize(c, v);
if (sz > maxsz) { maxsz = sz; };
v = v.next;
};
let pad: i64 = (maxsz + 7i64) & ~7i64;
return 8i64 + pad;
};
if (k == nkind.N_TENUM) {
if (t.lhs != nil) { return astsize(c, t.lhs); };
return 4i64;
};
if (k == nkind.N_TNAME) {
let nm: str = t.str;
let ps: i64 = primtypesize(nm);
if (ps >= 0i64) { return ps; };
let resolved: *node = resolvealias(c, t);
if (resolved != nil && resolved != t) {
return astsize(c, resolved);
};
};
return 0i64;
};
// astoffset — byte offset of `dot.str` inside the struct type of
// `dot.lhs`. Mirrors cstage cmd/wcc/check.c:932-961: peel one N_TPTR
// (for `p.field` where p is *Struct), require N_TSTRUCT, walk fields
// honouring per-field alignment, return -1 if the field name is
// absent so the caller can flag the error and fold to 0.
fn astoffset(c: *checker, dot: *node) i64 = {
if (dot == nil) { return -1i64; };
if (dot.kind != nkind.N_DOT) { return -1i64; };
let recv: *node = scruttype(c, dot.lhs);
if (recv == nil) { return -1i64; };
let rtyp: *node = resolvealias(c, unwrapbang(recv));
if (rtyp == nil) { return -1i64; };
if (rtyp.kind == nkind.N_TPTR) {
rtyp = resolvealias(c, unwrapbang(rtyp.lhs));
};
if (rtyp == nil) { return -1i64; };
if (rtyp.kind != nkind.N_TSTRUCT) { return -1i64; };
let off: i64 = 0i64;
let f: *node = rtyp.list;
for (f != nil) {
if (f.kind == nkind.N_TFIELD) {
let fa: i64 = astalign(c, f.lhs);
off = (off + fa - 1i64) & ~(fa - 1i64);
if (streq(f.str, dot.str)) { return off; };
off += astsize(c, f.lhs);
};
f = f.next;
};
return -1i64;
};
// arenau64tos — decimal string for the folded INTLIT's `str` field.
// Cstage uses aprintf("%llu") at the same site (cmd/wcc/check.c:921);
// wwstage cgen only reads `uval` for N_INTLIT codegen so `str` is
// just for the AST printer, but set it for parity with the parser's
// own literal-emit shape.
fn arenau64tos(a: *arena, v: u64) str = {
let buf: *u8 = amalloc(a, 24u64): *u8;
let i: i32 = 23;
buf[i] = 0u8;
if (v == 0u64) { i -= 1; buf[i] = 48u8; };
let n: u64 = v;
for (n > 0u64) {
i -= 1;
buf[i] = (48u64 + (n % 10u64)): u8;
n /= 10u64;
};
let r: str;
r.ptr = buf + (i: u64);
r.len = 23 - i;
return r;
};
// foldtointlit — mutate `n` in place to an N_INTLIT with value `v`.
// Used by the #42 size/align/offset intercepts so cgen sees the
// folded literal rather than an unresolved call. Mirrors cstage
// cmd/wcc/check.c:919-927 / :951-958.
fn foldtointlit(c: *checker, n: *node, v: i64) void = {
n.kind = nkind.N_INTLIT;
n.uval = v: u64;
n.str = arenau64tos(c.a, v: u64);
n.lhs = nil;
n.list = nil;
let empty: str;
n.tsuffix = empty;
};
// #61 A.5 helper: per-element slot size when `pt` appears inside a
// tuple. Mirrors cgenutil.ww slotsize TTUPLE — cstage's tuple ABI
// spills each element into its own register / 8B eightbyte, so narrow
// scalars pad to 8 (cgen's let_emit_size + AX:DX:CX positional layout).
// str/slice and composites consult `pt.size` so a future #1 bump on
// any primitive layout propagates through the typ.ww SSoT seed
// instead of getting baked into this detour. pointer/fn/chan stay
// 8; void contributes 0 (never appears in tuples emitted by user
// code, but kept for SSoT symmetry with cgen's N_TNAME-"void"
// fallback arm).
fn tupleelemslot(pt: *tinfo) u64 = {
if (pt == nil) { return 8u64; };
let pk: tykind = pt.kind;
if (pk == tykind.TY_VOID) { return 0u64; };
if (pk == tykind.TY_STR) { return pt.size; };
if (pk == tykind.TY_SLICE) { return pt.size; };
if (pk == tykind.TY_PTR || pk == tykind.TY_FN ||
pk == tykind.TY_CHAN || pk == tykind.TY_I64 ||
pk == tykind.TY_U64 || pk == tykind.TY_INT ||
pk == tykind.TY_UINT || pk == tykind.TY_UINTPTR ||
pk == tykind.TY_F64) { return 8u64; };
if (pk == tykind.TY_BOOL || pk == tykind.TY_RUNE ||
pk == tykind.TY_I8 || pk == tykind.TY_I16 ||
pk == tykind.TY_I32 || pk == tykind.TY_U8 ||
pk == tykind.TY_U16 || pk == tykind.TY_U32 ||
pk == tykind.TY_F32 || pk == tykind.TY_ENUM) { return 8u64; };
// Composite — struct/tuple/array/tagged carry their own slot total.
return pt.slotsize;
};
// #61 A.5 helper: per-field slot size mirroring cgenutil.ww
// registerstruct/fieldsize. Nested struct fields contribute their
// slot-padded total (si.totsize equivalent); primitives keep their
// natural width (struct interior packing is unaffected by stack-slot
// pad-to-8); arrays use their slot-padded element-stride * elen.
fn fieldslotsize(ft: *tinfo) u64 = {
if (ft == nil) { return 8u64; };
let fk: tykind = ft.kind;
if (fk == tykind.TY_STRUCT) { return ft.slotsize; };
if (fk == tykind.TY_ARRAY) { return ft.slotsize; };
if (fk == tykind.TY_TAGGED) { return ft.size; };
// str / slice read ft.size so the typ.ww SSoT seed is the single
// source for #1 (str→24) / #34 (slice graduation) — no hardcoded
// literal here to drift.
if (fk == tykind.TY_SLICE) { return ft.size; };
if (fk == tykind.TY_PTR || fk == tykind.TY_FN ||
fk == tykind.TY_CHAN) { return 8u64; };
if (fk == tykind.TY_STR) { return ft.size; };
// Primitives keep natural width inside structs (matches
// cgenutil fieldsize: primsize, not pad-to-8). TY_TUPLE inside a
// struct currently defaults to 8 in cgenutil — preserve that
// shape until a future graduation aligns the two.
if (fk == tykind.TY_BOOL || fk == tykind.TY_RUNE ||
fk == tykind.TY_I8 || fk == tykind.TY_I16 ||
fk == tykind.TY_I32 || fk == tykind.TY_I64 ||
fk == tykind.TY_U8 || fk == tykind.TY_U16 ||
fk == tykind.TY_U32 || fk == tykind.TY_U64 ||
fk == tykind.TY_INT || fk == tykind.TY_UINT ||
fk == tykind.TY_UINTPTR || fk == tykind.TY_F32 ||
fk == tykind.TY_F64 || fk == tykind.TY_ENUM) { return ft.size; };
return 8u64;
};
// #61 audit §1.8 — resolve a type-expression AST node to its *tinfo.
// Mirrors cstage's resolve_type (cmd/wcc/check.c:286-565) which
// produces ty_* singletons / arena-allocated composites from a Node*.
// Cache lives in c.tc (typ.ww) so the same shape can be reused across
// modules within one check pass. Rob+Drew convergence 2026-05-20: cgen
// reads sizes from here starting with slotsize in A.2; subsequent
// sub-commits graduate elemsize/fieldsize/letemitsize/etc. onto the
// same pivot.
//
// A.2 coverage: primitive TNAME singletons, TNAME aliases (via
// resolvealias), TBANG (inner unchanged — see iserror note), TPTR,
// TSLICE, TCHAN, TARRAY, TFN, TENUM, TTUPLE, TSTRUCT, TTAGGED. Size
// computation tracks cstage natural sizes; cgen's slot-padding
// contract (cmd/w6c/cgen.c let_emit_size:691-720 pads narrow scalars
// to 8B) stays in slotsize's fallback walker.
fn tinfofornode(c: *checker, n: *node) *tinfo = {
if (n == nil) { return nil; };
let cached: *tinfo = tinfocachelookup(c.tc, n);
if (cached != nil) { return cached; };
let r: *tinfo = nil;
let k: nkind = n.kind;
if (k == nkind.N_TNAME) {
let nm: str = n.str;
if (streq(nm, "void")) { r = c.tc.tyvoid; };
if (streq(nm, "bool")) { r = c.tc.tybool; };
if (streq(nm, "rune")) { r = c.tc.tyrune; };
if (streq(nm, "i8")) { r = c.tc.tyi8; };
if (streq(nm, "i16")) { r = c.tc.tyi16; };
if (streq(nm, "i32")) { r = c.tc.tyi32; };
if (streq(nm, "i64")) { r = c.tc.tyi64; };
if (streq(nm, "u8")) { r = c.tc.tyu8; };
if (streq(nm, "u16")) { r = c.tc.tyu16; };
if (streq(nm, "u32")) { r = c.tc.tyu32; };
if (streq(nm, "u64")) { r = c.tc.tyu64; };
if (streq(nm, "int")) { r = c.tc.tyint; };
if (streq(nm, "uint")) { r = c.tc.tyuint; };
if (streq(nm, "uintptr")) { r = c.tc.tyuintptr; };
if (streq(nm, "f32")) { r = c.tc.tyf32; };
if (streq(nm, "f64")) { r = c.tc.tyf64; };
if (streq(nm, "str")) { r = c.tc.tystr; };
if (streq(nm, "never")) { r = c.tc.tynever; };
if (streq(nm, "untyped_int")) { r = c.tc.tyuntypedint; };
if (streq(nm, "untyped_float")) { r = c.tc.tyuntypedfloat; };
if (streq(nm, "untyped_str")) { r = c.tc.tyuntypedstr; };
if (streq(nm, "untyped_rune")) { r = c.tc.tyuntypedrune; };
if (streq(nm, "untyped_bool")) { r = c.tc.tyuntypedbool; };
if (streq(nm, "untyped_nil")) { r = c.tc.tyuntypednil; };
if (r == nil) {
// Alias / user-defined name: resolve via scope and recurse.
// Mirrors astsize's TNAME fallback so the helpers stay in
// lockstep until A.2 collapses each cgen size-walker onto
// tinfo.size directly.
//
// #61 A.4: bind the resolved body too so future
// tinfofornode calls on either the TNAME or its target
// short-circuit on the cache hit instead of re-walking
// the chain. Pre-bind matches A.2's TSTRUCT/TFN/TTUPLE/
// TTAGGED cycle-break pattern (a self-referential
// struct field's *T → TNAME → body would otherwise
// re-enter the same chain).
let body: *node = resolvealias(c, n);
if (body != nil && body != n) {
let cached2: *tinfo = tinfocachelookup(c.tc, body);
if (cached2 != nil) {
r = cached2;
} else {
r = tinfofornode(c, body);
if (r != nil) {
tinfocachebind(c.tc, body, r);
};
};
};
};
} else { if (k == nkind.N_TBANG) {
// #61 audit §1.8: `!T` propagates the inner shape; cstage's
// resolve_type sets ty->iserror on the wrapper but no wwstage
// cgen reader consumes it yet, so A.1 drops the flag and
// returns the inner tinfo unchanged. Mirrors typeeqast's
// unwrapbang pre-walk; graduate alongside the first cgen
// site that needs iserror discrimination.
r = tinfofornode(c, n.lhs);
} else { if (k == nkind.N_TPTR) {
r = typeptr(c.a, tinfofornode(c, n.lhs));
} else { if (k == nkind.N_TSLICE) {
r = typeslice(c.a, tinfofornode(c, n.lhs));
} else { if (k == nkind.N_TCHAN) {
r = typechan(c.a, tinfofornode(c, n.lhs));
} else { if (k == nkind.N_TARRAY) {
// Cstage cmd/wcc/check.c:314-326: length must be an integer
// literal (`[_]T` keeps alen=0 as the inferred-length sentinel
// patched at letslotsize-time).
//
// #61 A.5: ti.size = natural (sub.size * elen), ti.slotsize =
// slot-padded (sub.slotsize * elen) — typearray handles both.
// Reverts A.4's r.size override (which conflated stride with
// natural size); the slot-padded stride now lives in slotsize
// where cgenutil's fast-path reads it.
let elen: u64 = 0u64;
if (n.rhs != nil) {
if (n.rhs.kind == nkind.N_INTLIT) { elen = n.rhs.uval; };
};
let sub: *tinfo = tinfofornode(c, n.lhs);
r = typearray(c.a, sub, elen);
} else { if (k == nkind.N_TFN) {
// Cstage cmd/wcc/check.c:437-466: function types are 8B / 8B
// (call-target pointer shape). Pre-bind before recursing into
// the return type so a recursive `type F = fn() F` self-ref
// doesn't spin (cycle-break mirror of the TSTRUCT/TTAGGED
// pattern below).
r = newtype(c.a, tykind.TY_FN);
r.size = 8u64;
r.align = 8u64;
r.slotsize = 8u64;
tinfocachebind(c.tc, n, r);
r.ret = tinfofornode(c, n.lhs);
} else { if (k == nkind.N_TENUM) {
// Cstage cmd/wcc/check.c:529-542: storage type's size/align
// (default i32 = 4B/4B). Cgen's slotsize-TENUM fallback pads
// to 8B per its stack-slot contract; tinfo.size carries the
// raw storage width so size(EnumT) folds to the correct value.
r = newtype(c.a, tykind.TY_ENUM);
let storage: *tinfo = nil;
if (n.lhs != nil) { storage = tinfofornode(c, n.lhs); };
if (storage == nil) { storage = c.tc.tyi32; };
r.sub = storage;
r.size = storage.size;
r.align = storage.align;
r.slotsize = storage.size;
} else { if (k == nkind.N_TTUPLE) {
// Cstage cmd/wcc/check.c:329-345: sum of element sizes with
// per-element alignment NOT padded — cstage uses raw sums for
// tuples and 8B-rounding lives at the call/return ABI layer.
// Pre-bind for cycle protection (recursive tuple shapes).
//
// #61 A.5: ti.size = natural sum (cstage parity); ti.slotsize
// = per-element slot sum mirroring cgenutil.ww:2018-2029
// slotsize TTUPLE — narrow scalars pad to 8 (cgen spills each
// tuple element into its own register / stack-slot eightbyte),
// composites contribute their own ti.slotsize.
r = newtype(c.a, tykind.TY_TUPLE);
tinfocachebind(c.tc, n, r);
let total: u64 = 0u64;
let slottotal: u64 = 0u64;
let maxal: u64 = 1u64;
let p: *node = n.list;
for (p != nil) {
let pt: *tinfo = tinfofornode(c, p);
if (pt != nil) {
if (pt.align > maxal) { maxal = pt.align; };
total += pt.size;
slottotal += tupleelemslot(pt);
};
p = p.next;
};
r.size = total;
r.align = maxal;
r.slotsize = slottotal;
} else { if (k == nkind.N_TSTRUCT) {
// Cstage cmd/wcc/check.c:468-527: per-field alignment, max
// align for the whole record, total rounded up to alignment.
// Anonymous-embed promotion is deferred (#13).
//
// Pre-bind into the cache BEFORE walking fields so a
// self-referential pointer field (e.g., `next: *node` inside
// `type node = struct {..., next: *node, ...}`) terminates:
// the inner tinfofornode(TNAME(node)) resolvealias-recurses
// back to this same body node, hits the cache, and returns
// the in-progress stub. r.size is filled in below; the stub's
// only consumer during the recursion is typeptr (8B/8B
// regardless of pointee size), so partial-fill is safe.
//
// #61 A.5: alongside the natural layout (cstage parity), walk
// the same fields with the slot-padded sizing cgenutil.ww
// registerstruct uses (fieldsize → si.totsize for nested
// struct; size-derived alignment; final round to 8). That
// slot total lands in ti.slotsize so the cgen fast-path can
// graduate TY_STRUCT off the AST walker.
r = newtype(c.a, tykind.TY_STRUCT);
tinfocachebind(c.tc, n, r);
let off: u64 = 0u64;
let maxalign: u64 = 1u64;
let soff: u64 = 0u64;
let f: *node = n.list;
for (f != nil) {
if (f.kind == nkind.N_TFIELD) {
let ft: *tinfo = tinfofornode(c, f.lhs);
if (ft != nil) {
if (ft.align > maxalign) { maxalign = ft.align; };
if (ft.align > 0u64) {
off = (off + ft.align - 1u64) & ~(ft.align - 1u64);
};
off += ft.size;
// Slot-padded layout (mirror of cgenutil
// fieldsize + registerstruct align rules).
let fsz: u64 = fieldslotsize(ft);
let faln: u64 = 1u64;
if (fsz >= 8u64) { faln = 8u64; }
else { if (fsz >= 4u64) { faln = 4u64; }
else { if (fsz >= 2u64) { faln = 2u64; }; }; };
if ((soff & (faln - 1u64)) != 0u64) {
soff = (soff + faln - 1u64) & ~(faln - 1u64);
};
soff += fsz;
};
};
f = f.next;
};
if (maxalign > 0u64) {
r.size = (off + maxalign - 1u64) & ~(maxalign - 1u64);
};
r.align = maxalign;
if ((soff & 7u64) != 0u64) {
soff = (soff + 7u64) & ~7u64;
};
r.slotsize = soff;
} else { if (k == nkind.N_TTAGGED) {
// Cstage cmd/wcc/check.c:347-435: 8B tag + max(variant)
// rounded up to 8. Pre-bind for cycle protection (recursive
// sum-type shapes through NAMED variants).
r = newtype(c.a, tykind.TY_TAGGED);
tinfocachebind(c.tc, n, r);
// #61 A.3 nullable fold: `(*T | void)` collapses to a single
// 8B pointer slot, null is the void variant. Mirrors
// cmd/wcc/check.c:412-426 — bare TNAME("void"), not `!void`,
// and not NAMED — so wwstage slotsize fast-path can graduate
// TY_TAGGED off the AST-walker fallback. Match before counting
// variants so the 8B fold lands in tinfo.size directly.
let a: *node = n.list;
if (a != nil) {
let b: *node = a.next;
if (b != nil && b.next == nil) {
let aptr: bool = (a.kind == nkind.N_TPTR);
let bptr: bool = (b.kind == nkind.N_TPTR);
let avoid: bool = (a.kind == nkind.N_TNAME);
if (avoid) { avoid = streq(a.str, "void"); };
let bvoid: bool = (b.kind == nkind.N_TNAME);
if (bvoid) { bvoid = streq(b.str, "void"); };
let isnull: bool = false;
if (aptr) { if (bvoid) { isnull = true; }; };
if (avoid) { if (bptr) { isnull = true; }; };
if (isnull) {
r.size = 8u64;
r.align = 8u64;
r.nullable = 1;
r.slotsize = 8u64;
tinfocachebind(c.tc, n, r);
return r;
};
};
};
let maxsz: u64 = 0u64;
let al: u64 = 8u64;
let v: *node = n.list;
for (v != nil) {
let vt: *tinfo = tinfofornode(c, v);
if (vt != nil) {
if (vt.size > maxsz) { maxsz = vt.size; };
if (vt.align > al) { al = vt.align; };
};
v = v.next;
};
let pad: u64 = (maxsz + 7u64) & ~7u64;
r.size = 8u64 + pad;
r.align = al;
r.slotsize = 8u64 + pad;
};};};};};};};};};};};
if (r != nil) {
// #61 A.5: any arm that didn't set slotsize gets ti.size as
// the default (covers primitives via prim() + the ptr/slice/
// chan paths which already populate slotsize, plus TBANG which
// inherits the inner's tinfo unchanged).
if (r.slotsize == 0u64) { r.slotsize = r.size; };
tinfocachebind(c.tc, n, r);
};
return r;
};
// exprtype — best-effort type-AST inference for an expression
// node. Handles literals, identifiers, calls, and casts; returns
// nil for shapes we don't statically know (binary ops, struct
// field access into non-primitive types, etc).
fn exprtype(c: *checker, e: *node) *node = {
if (e == nil) { return nil; };
let k: nkind = e.kind;
// #61 audit §1.8 — A.2 widens A.1's single N_INTLIT population to
// every primitive literal arm + N_IDENT. Cgen size walkers
// (slotsize first; elemsize/fieldsize/letemitsize follow) consult
// node.type_ as the SSoT; populating literals + idents closes the
// loop from the read side.
if (k == nkind.N_INTLIT) {
let tn: *node = mktname(c, "untyped_int");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_FLOATLIT) {
let tn: *node = mktname(c, "untyped_float");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_STRLIT) {
let tn: *node = mktname(c, "str");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_RUNELIT) {
let tn: *node = mktname(c, "rune");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_TRUE) {
let tn: *node = mktname(c, "bool");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_FALSE) {
let tn: *node = mktname(c, "bool");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_VOIDLIT) {
let tn: *node = mktname(c, "void");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_NIL) {
let tn: *node = mktname(c, "untyped_nil");
e.type_ = tinfofornode(c, tn): *void;
return tn;
};
if (k == nkind.N_IDENT) {
let s: *sym = scopelookup(c.cur, e.str);
if (s == nil) { return nil; };
if (s.decl == nil) { return nil; };
let t: *node = s.decl.lhs;
// Propagate the declared type's tinfo onto the use site so
// downstream cgen walkers can read n.type_ off an ident.
if (t != nil) {
if (t.type_ != nil) {
e.type_ = t.type_;
} else {
let ti: *tinfo = tinfofornode(c, t);
if (ti != nil) {
e.type_ = ti: *void;
t.type_ = ti: *void;
};
};
};
return t;
};
if (k == nkind.N_CAST) {
// `expr: T` — explicit cast; the type expr is e.rhs.
return e.rhs;
};
if (k == nkind.N_CALL) {
let callee: *node = e.lhs;
if (callee == nil) { return nil; };
// #31: synthesize the `alloc(value)` / `alloc([], n)` builtin
// return shape so checkletassign sees the same `(*T | nomem)` /
// `([]T | nomem)` cstage's check.c stamps at L981-1006. Without
// this, exprtype returns the seeded decl's nil lhs and the let
// silently accepts `let p: *T = alloc(v);` — rule 10 trap.
// Same-module gate mirrors cstage's `c->cur_mod &&
// scope_lookup_in_module(...)` check from task #23.
if (callee.kind == nkind.N_IDENT) {
if (streq(callee.str, "alloc")) {
let shadowed: bool = false;
if (c.curmod.len > 0) {
if (scopelookupinmodule(c.cur, c.curmod, "alloc") != nil) {
shadowed = true;
};
};
if (!shadowed) {
if (e.list != nil) {
// Slice form: `alloc([], n)`.
if (e.list.kind == nkind.N_ARRLIT) {
if (e.list.list == nil) {
if (e.list.next != nil) {
if (e.list.next.next == nil) {
let sl: *node = newnode(c.a, nkind.N_TSLICE, "", 0, 0);
sl.lhs = mktname(c, "u8");
let nome: *node = mktname(c, "nomem");
sl.next = nome;
let tt: *node = newnode(c.a, nkind.N_TTAGGED, "", 0, 0);
tt.list = sl;
return tt;
};
};
};
};
// Value form: `alloc(value)`.
if (e.list.next == nil) {
let argt: *node = exprtype(c, e.list);
let ptr: *node = newnode(c.a, nkind.N_TPTR, "", 0, 0);
ptr.lhs = argt;
let nome: *node = mktname(c, "nomem");
ptr.next = nome;
let tt: *node = newnode(c.a, nkind.N_TTAGGED, "", 0, 0);
tt.list = ptr;
return tt;
};
};
};
};
};
// #42: size(T) / align(T) / offset(e.f) typed-builtin intercepts.
// Fold the N_CALL in place to an N_INTLIT so cgen never sees an
// unresolved size/align/offset symbol. Same-module shadow gate
// mirrors the alloc precedent (#23) so a user `fn size(...)`
// inside this module suppresses the builtin. Mirrors cstage
// cmd/wcc/check.c:907-960.
if (callee.kind == nkind.N_IDENT) {
let bname: str = callee.str;
let issize: bool = streq(bname, "size");
let isalign: bool = streq(bname, "align");
let isoffset: bool = streq(bname, "offset");
if (issize || isalign || isoffset) {
let shadowed: bool = false;
if (c.curmod.len > 0) {
if (scopelookupinmodule(c.cur, c.curmod, bname) != nil) {
shadowed = true;
};
};
if (!shadowed) {
if (e.list != nil) {
if (issize) {
let v: i64 = astsize(c, e.list);
foldtointlit(c, e, v);
return mktname(c, "i32");
};
if (isalign) {
let v: i64 = astalign(c, e.list);
foldtointlit(c, e, v);
return mktname(c, "i32");
};
// offset(e.f): the arg is a value expression
// (N_DOT), parsed via parsearglist — not a
// type expression.
if (isoffset) {
if (e.list.next == nil && e.list.kind == nkind.N_DOT) {
let off: i64 = astoffset(c, e.list);
if (off < 0i64) {
os.write(2, "offset: no field '".ptr, 18u64);
os.write(2, e.list.str.ptr, e.list.str.len: u64);
os.write(2, "'\n".ptr, 2u64);
c.errs += 1;
off = 0i64;
};
foldtointlit(c, e, off);
return mktname(c, "i32");
};
};
};
};
};
};
let nm: str;
nm.ptr = nil; nm.len = 0;
if (callee.kind == nkind.N_IDENT) { nm = callee.str; };
if (callee.kind == nkind.N_DOT) { nm = callee.str; };
if (nm.len == 0) { return nil; };
// #56: bare-leaf N_IDENT calls go through scopelookupprefer so
// `foo()` inside module M binds to M.foo rather than another
// module's same-leaf foo at the head of the flat scope bucket.
// Mirrors cstage cexpr N_IDENT routing through
// scope_lookup_prefer with c->cur_mod. N_DOT keeps the bare
// scopelookup — its module-qualified resolution is a separate
// gap (parser stores the leaf in callee.str; mod is in
// callee.lhs.str, not consumed here yet).
let s: *sym = nil;
if (callee.kind == nkind.N_IDENT) {
s = scopelookupprefer(c.cur, c.curmod, nm);
} else {
s = scopelookup(c.cur, nm);
};
if (s == nil) { return nil; };
if (s.skind != skind.SK_FN) { return nil; };
if (s.decl == nil) { return nil; };
return s.decl.lhs; // fn-decl's lhs is the return type
};
if (k == nkind.N_TRYPROP) {
// success unwrap: the success-variant type of operand's
// tagged union.
let opt: *node = exprtype(c, e.lhs);
let ou: *node = resolvealias(c, unwrapbang(opt));
if (ou == nil) { return nil; };
if (ou.kind != nkind.N_TTAGGED) { return nil; };
// Hare semantics: success = first non-error variant if
// any !-flag is present; else first variant.
if (taggedhaserr(c, ou)) {
let v: *node = ou.list;
for (v != nil) {
if (!iserrvariant(c, ou, v)) { return v; };
v = v.next;
};
return nil;
};
return ou.list;
};
if (k == nkind.N_TRYUNW) {
// `e!` abort-on-error unwrap; success variant is what the
// receiver gets, identical to `?` shape modulo control flow.
// #31: required so `let p: *T = alloc(v)!;` resolves to *T.
let opt: *node = exprtype(c, e.lhs);
let ou: *node = resolvealias(c, unwrapbang(opt));
if (ou == nil) { return nil; };
if (ou.kind != nkind.N_TTAGGED) { return nil; };
if (taggedhaserr(c, ou)) {
let v: *node = ou.list;
for (v != nil) {
if (!iserrvariant(c, ou, v)) { return v; };
v = v.next;
};
return nil;
};
return ou.list;
};
if (k == nkind.N_TYPEASSERT) {
// `e as T` → T
return e.rhs;
};
if (k == nkind.N_TYPETEST) {
// `e is T` → bool
return mktname(c, "bool");
};
return nil;
};
// isuntypedint / is_str_like / is_bool_like — helpers used
// by the assignability check below to allow common AST shapes
// through without needing real type inference.
fn isuntypedint(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind != nkind.N_TNAME) { return false; };
return streq(t.str, "untyped_int");
};
fn isuntypedfloat(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind != nkind.N_TNAME) { return false; };
return streq(t.str, "untyped_float");
};
fn isuntypednil(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind != nkind.N_TNAME) { return false; };
return streq(t.str, "untyped_nil");
};
// isinttypeast — int-typed AST node. Either a primitive int name
// (i8..i64/u8..u64/int/uint/uintptr/rune) or an N_TENUM. Floats are
// excluded so the enum↔int reinterpret in checkisas (#52) refuses a
// surprise `enum as f64` shape. Mirrors cstage's type_isint
// (cmd/wcc/type.c) restricted to the kinds reachable from AST.
fn isinttypeast(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind == nkind.N_TENUM) { return true; };
if (t.kind != nkind.N_TNAME) { return false; };
let s: str = t.str;
if (streq(s, "i8")) { return true; };
if (streq(s, "i16")) { return true; };
if (streq(s, "i32")) { return true; };
if (streq(s, "i64")) { return true; };
if (streq(s, "u8")) { return true; };
if (streq(s, "u16")) { return true; };
if (streq(s, "u32")) { return true; };
if (streq(s, "u64")) { return true; };
if (streq(s, "int")) { return true; };
if (streq(s, "uint")) { return true; };
if (streq(s, "uintptr")) { return true; };
if (streq(s, "rune")) { return true; };
return false;
};
fn isnumerictname(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind != nkind.N_TNAME) { return false; };
let s: str = t.str;
if (streq(s, "i8")) { return true; };
if (streq(s, "i16")) { return true; };
if (streq(s, "i32")) { return true; };
if (streq(s, "i64")) { return true; };
if (streq(s, "u8")) { return true; };
if (streq(s, "u16")) { return true; };
if (streq(s, "u32")) { return true; };
if (streq(s, "u64")) { return true; };
if (streq(s, "int")) { return true; };
if (streq(s, "uint")) { return true; };
if (streq(s, "uintptr")) { return true; };
if (streq(s, "rune")) { return true; };
if (streq(s, "f32")) { return true; };
if (streq(s, "f64")) { return true; };
return false;
};
fn isstrtname(t: *node) bool = {
if (t == nil) { return false; };
if (t.kind != nkind.N_TNAME) { return false; };
return streq(t.str, "str");
};
// isassignable — AST-level approximation of C check.c
// type_assignable. Returns true when we know the assignment is
// OK, false only when we're confident it isn't, and "skip" (true)
// when we can't tell — to avoid false positives. The trailing bool
// `confident` lets the caller decide whether to emit an error
// when the result is false: if !confident, the caller should not
// flag it.
fn isassignable(c: *checker, dst: *node, src: *node, confident: *bool) bool = {
*confident = false;
if (dst == nil) { return true; }; // no declared target
if (src == nil) { return true; }; // unknown src type
*confident = true;
let du: *node = resolvealias(c, unwrapbang(dst));
let su: *node = resolvealias(c, unwrapbang(src));
if (du == nil) { *confident = false; return true; };
if (su == nil) { *confident = false; return true; };
if (typeeqast(du, su)) { return true; };
// untyped numeric → any numeric named type.
if (isuntypedint(su)) {
if (isnumerictname(du)) { return true; };
// (T | ...) tagged: only OK if some variant accepts untyped_int.
if (du.kind == nkind.N_TTAGGED) {
let v: *node = du.list;
for (v != nil) {
let vu: *node = resolvealias(c, unwrapbang(v));
if (vu != nil) {
if (isnumerictname(vu)) { return true; };
};
v = v.next;
};
*confident = false;
return true;
};
// Known non-numeric primitive: confidently wrong.
if (du.kind == nkind.N_TNAME) {
if (streq(du.str, "bool")) { return false; };
if (streq(du.str, "void")) { return false; };
if (streq(du.str, "str")) { return false; };
};
// Unknown shapes: stay quiet.
*confident = false;
return true;
};
if (isuntypedfloat(su)) {
if (isnumerictname(du)) { return true; };
if (du.kind == nkind.N_TNAME) {
if (streq(du.str, "bool")) { return false; };
if (streq(du.str, "void")) { return false; };
if (streq(du.str, "str")) { return false; };
};
*confident = false;
return true;
};
if (isuntypednil(su)) {
// nil → ptr/slice/chan/fn/nullable
if (du.kind == nkind.N_TPTR) { return true; };
if (du.kind == nkind.N_TSLICE) { return true; };
if (du.kind == nkind.N_TCHAN) { return true; };
if (du.kind == nkind.N_TFN) { return true; };
// nullable `(*T | void)` — already accepted by typeeqast
// when matched whole; nil is OK there too.
if (du.kind == nkind.N_TTAGGED) {
let v: *node = du.list;
for (v != nil) {
if (v.kind == nkind.N_TPTR) { return true; };
if (v.kind == nkind.N_TSLICE){ return true; };
v = v.next;
};
};
*confident = false;
return true;
};
// Tagged-union variant inclusion: src is one of dst's variants.
if (du.kind == nkind.N_TTAGGED && su.kind != nkind.N_TTAGGED) {
// #55: nominal-first compare. Cstage variant_match
// (cmd/wcc/check.c:90-100) takes NAMED types as
// pointer-identical, so two `err`s match before bodies
// are resolved. Wwstage's typeeqast already does
// string-nominal on N_TNAME, but pre-fix this branch
// resolvealias-d both v and src to their bodies (e.g.
// N_TSTRUCT), and typeeqast's conservative struct arm
// returned false — `return e;` inside `fn f() (void | err)`
// got flagged. Compare surface forms first; fall through
// to resolved compare only when the surface mismatches
// (covers structurally-anonymous variant cases that
// resolvealias actually disambiguates). Residual: bare-vs-
// qualified TNAME (`(void | modM.err)` variant vs bare `err`
// inside modM) still misses both arms — filed as #57.
let srcraw: *node = unwrapbang(src);
let v: *node = du.list;
for (v != nil) {
let vraw: *node = unwrapbang(v);
if (typeeqast(vraw, srcraw)) { return true; };
let vu: *node = resolvealias(c, vraw);
if (vu != nil) {
if (typeeqast(vu, su)) { return true; };
};
v = v.next;
};
return false;
};
// tagged → tagged: structural variant list compare. Skip
// (don't be confident) — common when forwarding a fallible
// return through another fn with the same shape but possibly
// a different surface spelling.
if (du.kind == nkind.N_TTAGGED && su.kind == nkind.N_TTAGGED) {
*confident = false;
return true;
};
// tagged → non-tagged: requires `?` / `!` / match to project a
// variant. #31: this is what traps `let p: *T = alloc(v);`
// where the builtin returns `(*T | nomem)` and the LHS is bare.
if (su.kind == nkind.N_TTAGGED && du.kind != nkind.N_TTAGGED) {
return false;
};
// Two known primitives with different names are confidently
// incompatible. `i32 ↔ bool`, `str ↔ i32`, etc.
if (du.kind == nkind.N_TNAME && su.kind == nkind.N_TNAME) {
let known_d: bool = isnumerictname(du) || isstrtname(du);
if (!known_d) { if (streq(du.str, "bool")) { known_d = true; }; };
if (!known_d) { if (streq(du.str, "void")) { known_d = true; }; };
let known_s: bool = isnumerictname(su) || isstrtname(su);
if (!known_s) { if (streq(su.str, "bool")) { known_s = true; }; };
if (!known_s) { if (streq(su.str, "void")) { known_s = true; }; };
if (known_d) {
if (known_s) {
// Both primitives, different names → no.
return false;
};
};
};
// Anything else: don't claim confidence.
*confident = false;
return true;
};
// ---- match exhaustiveness --------------------------------------------
//
// For every match arm, verify that every variant of the scrutinee's
// tagged-union type is handled by some case (or a default arm
// exists). Multi-pattern `case A | B =>` covers all alts.
fn casecovers(c: *checker, cs: *node, want: *node) bool = {
if (cs.lhs != nil) {
if (typeeqast(cs.lhs, want)) { return true; };
};
let alt: *node = cs.list;
for (alt != nil) {
if (typeeqast(alt, want)) { return true; };
alt = alt.next;
};
return false;
};
fn errmatchvariant(c: *checker, n: *node, vname: *node) void = {
os.write(2, "match: variant not handled".ptr, 26u64);
if (vname != nil) {
if (vname.kind == nkind.N_TNAME) {
os.write(2, " (".ptr, 2u64);
os.write(2, vname.str.ptr, vname.str.len: u64);
os.write(2, ")".ptr, 1u64);
};
};
os.write(2, "\n".ptr, 1u64);
c.errs += 1;
};
// casevariantin — true iff `pat` (a `case T` pattern, including
// each alt of a multi-pattern) names a variant of the tagged
// union `tagged`.
fn casevariantin(tagged: *node, pat: *node) bool = {
let v: *node = tagged.list;
for (v != nil) {
if (typeeqast(v, pat)) { return true; };
v = v.next;
};
return false;
};
fn errbadcase(c: *checker, pat: *node) void = {
os.write(2, "case: not a variant of scrutinee".ptr, 32u64);
if (pat != nil) {
if (pat.kind == nkind.N_TNAME) {
os.write(2, " (".ptr, 2u64);
os.write(2, pat.str.ptr, pat.str.len: u64);
os.write(2, ")".ptr, 1u64);
};
};
os.write(2, "\n".ptr, 1u64);
c.errs += 1;
};
fn checkmatchexhaust(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) { return; };
let st: *node = scruttype(c, n.lhs);
let u: *node = resolvealias(c, unwrapbang(st));
if (u == nil) { return; };
if (u.kind != nkind.N_TTAGGED) { return; };
// Validity: every `case T` pattern (and multi-pattern alts)
// must name a variant of u. Catches typos and dead arms that
// the dispatch would never reach.
let cs0: *node = n.list;
for (cs0 != nil) {
if (cs0.lhs != nil) {
if (!casevariantin(u, cs0.lhs)) {
errbadcase(c, cs0.lhs);
};
let alt: *node = cs0.list;
for (alt != nil) {
if (!casevariantin(u, alt)) {
errbadcase(c, alt);
};
alt = alt.next;
};
};
cs0 = cs0.next;
};
// Default arm absorbs anything; skip exhaustiveness.
let cs: *node = n.list;
for (cs != nil) {
if (cs.lhs == nil) { return; }; // default
cs = cs.next;
};
// For each variant of u, look for a covering case.
let v: *node = u.list;
for (v != nil) {
let covered: bool = false;
let cs2: *node = n.list;
for (cs2 != nil) {
if (casecovers(c, cs2, v)) {
covered = true;
cs2 = nil;
} else {
cs2 = cs2.next;
};
};
if (!covered) { errmatchvariant(c, n, v); };
v = v.next;
};
};
// ---- let init / return assignability --------------------------------
//
// AST-level approximation: when we can infer src's type and dst is
// explicitly declared, verify isassignable. We only emit an error
// when isassignable says "false with confidence." If we can't tell
// (binary ops, complex exprs we don't infer), we stay quiet — full
// type inference lives only on the C side.
fn errnotassign(c: *checker, dst: *node, src: *node, where: str) void = {
os.write(2, where.ptr, where.len: u64);
os.write(2, ": not assignable".ptr, 16u64);
if (src != nil) {
if (src.kind == nkind.N_TNAME) {
os.write(2, " (".ptr, 2u64);
os.write(2, src.str.ptr, src.str.len: u64);
os.write(2, " → ".ptr, 5u64);
if (dst != nil) {
if (dst.kind == nkind.N_TNAME) {
os.write(2, dst.str.ptr, dst.str.len: u64);
};
};
os.write(2, ")".ptr, 1u64);
};
};
os.write(2, "\n".ptr, 1u64);
c.errs += 1;
};
fn checkletassign(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) { return; }; // no declared type, nothing to check
if (n.rhs == nil) { return; }; // no init
let src: *node = exprtype(c, n.rhs);
if (src == nil) { return; }; // can't infer
// #45: alloc([], n) defers element type to the let-init context
// (Hare-style). exprtype's alloc-slice branch synthesizes
// ([]u8 | nomem) / []u8 (for the ?/! wrap) with no LHS context;
// when the let declares []T, retype src to []T / ([]T | nomem)
// so isassignable sees exact equality. cgenstmt cglet drives the
// element size from n.lhs already (cmd/wcc/cgenstmt.ww), so this
// stays symmetric with cstage check.c clet's parallel retype.
if (n.lhs.kind == nkind.N_TSLICE) {
let wrapped: bool = false;
let inner: *node = n.rhs;
if (inner.kind == nkind.N_TRYPROP) {
wrapped = true;
inner = inner.lhs;
} else { if (inner.kind == nkind.N_TRYUNW) {
wrapped = true;
inner = inner.lhs;
}; };
if (inner != nil && inner.kind == nkind.N_CALL) {
let callee: *node = inner.lhs;
let a0: *node = inner.list;
let a1: *node = nil;
let a2: *node = nil;
if (a0 != nil) { a1 = a0.next; };
if (a1 != nil) { a2 = a1.next; };
if (callee != nil
&& callee.kind == nkind.N_IDENT
&& streq(callee.str, "alloc")
&& a0 != nil && a0.kind == nkind.N_ARRLIT
&& a0.list == nil
&& a1 != nil && a2 == nil) {
let shadowed: bool = false;
if (c.curmod.len > 0) {
if (scopelookupinmodule(c.cur, c.curmod, "alloc") != nil) {
shadowed = true;
};
};
if (!shadowed) {
let sl: *node = newnode(c.a, nkind.N_TSLICE, "", 0, 0);
sl.lhs = n.lhs.lhs;
if (wrapped) {
src = sl;
} else {
let nome: *node = mktname(c, "nomem");
sl.next = nome;
let tt: *node = newnode(c.a, nkind.N_TTAGGED, "", 0, 0);
tt.list = sl;
src = tt;
};
};
};
};
};
let conf: bool = false;
let ok: bool = isassignable(c, n.lhs, src, &conf);
if (!conf) { return; };
if (!ok) { errnotassign(c, n.lhs, src, "let"); };
};
fn checkretassign(c: *checker, n: *node) void = {
if (n == nil) { return; };
if (n.lhs == nil) {
// bare `return;` — OK iff fnret is void or a tagged union
// with a void variant. Skip flagging for now; cgen handles
// the void-variant tag synthesis already.
return;
};
if (c.fnret == nil) { return; };
let src: *node = exprtype(c, n.lhs);
if (src == nil) { return; };
let conf: bool = false;
let ok: bool = isassignable(c, c.fnret, src, &conf);
if (!conf) { return; };
if (!ok) { errnotassign(c, c.fnret, src, "return"); };
};
// ---- is / as validity ------------------------------------------------
//
// `e is T` and `e as T` require that e's declared type be a tagged
// union and that T name one of its variants. Operates on AST type
// expressions; falls back silently when we can't determine e's
// type (matches the case-variant rule for match).
fn checkisas(c: *checker, n: *node) void = {
if (n == nil) { return; };
// e is in n.lhs (value), T is in n.rhs (type expr).
let st: *node = scruttype(c, n.lhs);
let u: *node = resolvealias(c, unwrapbang(st));
if (u == nil) { return; };
// #52: enum ↔ int reinterpret (`enum as intT` / `intT as enum`).
// Mirrors cstage cmd/wcc/check.c:1346-1357 — N_TYPEASSERT with an
// enum on either side and integer types on both reinterprets in
// the same register, no tag check involved. Returns early before
// the tagged-union gate so lib/time/instant.ww `(c as i32)` and
// the lib/os syscall casts stop false-positiving. `is` (TYPETEST)
// stays rejected on non-tagged operands — cstage cmd/wcc/check.c
// gates the bypass on N_TYPEASSERT only.
if (n.kind == nkind.N_TYPEASSERT) {
let v: *node = resolvealias(c, unwrapbang(n.rhs));
let lhsenum: bool = false;
let rhsenum: bool = false;
if (u != nil) { if (u.kind == nkind.N_TENUM) { lhsenum = true; }; };
if (v != nil) { if (v.kind == nkind.N_TENUM) { rhsenum = true; }; };
if (lhsenum || rhsenum) {
if (isinttypeast(u)) { if (isinttypeast(v)) { return; }; };
};
};
if (u.kind != nkind.N_TTAGGED) {
os.write(2, "is/as: operand is not a tagged union\n".ptr, 37u64);
c.errs += 1;
return;
};
let want: *node = n.rhs;
if (want == nil) { return; };
if (!casevariantin(u, want)) {
os.write(2, "is/as: not a variant of operand".ptr, 31u64);
if (want.kind == nkind.N_TNAME) {
os.write(2, " (".ptr, 2u64);
os.write(2, want.str.ptr, want.str.len: u64);
os.write(2, ")".ptr, 1u64);
};
os.write(2, "\n".ptr, 1u64);
c.errs += 1;
};
};
// ---- ? subset propagation --------------------------------------------
//
// For `expr?`, the operand's error subset must be a subset of the
// enclosing fn's return-type variants. Mirrors C check.c. Operand
// is nkind.N_TRYPROP; its lhs is the value-bearing expr; we look at the
// expr's *declared* type for nkind.N_IDENT/nkind.N_CALL cases.
fn exprtypeoftry(c: *checker, e: *node) *node = {
if (e == nil) { return nil; };
if (e.kind == nkind.N_IDENT) {
let s: *sym = scopelookup(c.cur, e.str);
if (s == nil) { return nil; };
if (s.decl == nil) { return nil; };
return s.decl.lhs;
};
if (e.kind == nkind.N_CALL) {
// callee return type lookup: callee is e.lhs (nkind.N_IDENT or
// nkind.N_DOT). We need the fn-decl's lhs (return-type AST).
let callee: *node = e.lhs;
if (callee == nil) { return nil; };
let nm: str;
nm.ptr = nil; nm.len = 0;
if (callee.kind == nkind.N_IDENT) { nm = callee.str; };
if (callee.kind == nkind.N_DOT) { nm = callee.str; };
if (nm.len == 0) { return nil; };
let s: *sym = scopelookup(c.cur, nm);
if (s == nil) { return nil; };
if (s.skind != skind.SK_FN) { return nil; };
if (s.decl == nil) { return nil; };
return s.decl.lhs;
};
return nil;
};
fn checktryprop(c: *checker, n: *node) void = {
if (n == nil) { return; };
let t: *node = exprtypeoftry(c, n.lhs);
let u: *node = resolvealias(c, unwrapbang(t));
if (u == nil) { return; };
if (u.kind != nkind.N_TTAGGED) { return; };
// Does the operand have any error variants?
let haserr: bool = false;
let v: *node = u.list;
for (v != nil) {
if (iserrvariant(c, u, v)) { haserr = true; };
v = v.next;
};
if (!haserr) { return; };
// Enclosing fn must return a tagged union with each operand
// error variant present.
let r: *node = resolvealias(c, unwrapbang(c.fnret));
if (r == nil) {
os.write(2, "?: enclosing fn has no tagged-union return\n".ptr, 43u64);
c.errs += 1;
return;
};
if (r.kind != nkind.N_TTAGGED) {
os.write(2, "?: enclosing fn return is not tagged\n".ptr, 37u64);
c.errs += 1;
return;
};
let ev: *node = u.list;
for (ev != nil) {
if (iserrvariant(c, u, ev)) {
let found: bool = false;
let rv: *node = r.list;
for (rv != nil) {
if (typeeqast(rv, ev)) {
found = true;
rv = nil;
} else { rv = rv.next; };
};
if (!found) {
os.write(2, "?: error variant not in enclosing return\n".ptr, 41u64);
c.errs += 1;
};
};
ev = ev.next;
};
};
// install_param — when entering a fn body, define its params in a
// fresh local scope.
//
// TODO(#11): cstage check.c (post-#32) errors `param '%s' redeclared`
// when two params share a name. The fn body's scope IS fresh here
// (resolvefnbody opens it before calling us), so guarding scopedefine's
// nil return would be sound — but we defer until #11 wires checkfile
// into w6c_ww so the diagnostic class lands as a single coordinated
// step rather than dribbling in. Matches the cstage-only neg-case
// precedent at test/wcc/708 + test/wcc/696.
fn installparams(c: *checker, params: *node) void = {
let p: *node = params;
for (p != nil) {
if (p.kind == nkind.N_PARAM) {
let nm: str = p.str;
if (nm.len > 0) {
checkmoduleshadow(c, nm, "param");
scopedefine(c.cur, nm, skind.SK_PARAM, nil, p);
};
};
p = p.next;
};
};
// resolvefnbody — open a child scope for the fn, install its params,
// then walk the body. Local lets installed by walk_stmt (a future
// extension); for the current pass we just resolve-walk without
// per-statement scopes.
fn resolvefnbody(c: *checker, fnnode: *node) void = {
let outer: *scope = c.cur;
c.cur = newscope(c.a, c.cur);
installparams(c, fnnode.list);
// #61 audit §1.8 — A.2: walk each param's declared type-expr so
// tinfofornode stamps n.type_ on it. installparams binds the name
// but never recurses into the type; without this, cgen's slotsize
// fast-path hits the fallback for every param load/store.
let p: *node = fnnode.list;
for (p != nil) {
if (p.kind == nkind.N_PARAM) {
if (p.lhs != nil) { resolvewalk(c, p.lhs); };
};
p = p.next;
};
let prevret: *node = c.fnret;
c.fnret = fnnode.lhs; // return type AST, used by `?` check
if (fnnode.body != nil) {
resolvewalk(c, fnnode.body);
};
c.fnret = prevret;
c.cur = outer;
};
export fn checkinit(c: *checker, a: *arena, tc: *tctx) void = {
c.a = a;
c.tc = tc;
c.top = newscope(a, nil);
c.cur = c.top;
c.nresolved = 0;
c.nunresolved = 0;
c.errs = 0;
c.verbose = 0;
c.fnret = nil;
let empty: str;
c.curmod = empty;
c.file = nil;
seedprimitives(c);
};
export fn checkfile(c: *checker, file: *node) void = {
if (file == nil) { return; };
if (file.kind != nkind.N_FILE) { return; };
c.file = file;
// Pass 1: install all top-level names.
let d: *node = file.list;
for (d != nil) {
installdecl(c, file, d);
d = d.next;
};
// Pass 2: walk decl bodies/types and resolve identifiers.
// Track the per-decl module bareword so bare-leaf lookups inside
// the body prefer same-module entries over alphabetically-earlier
// same-leaf imports.
d = file.list;
for (d != nil) {
c.curmod = declmod(file, d);
let k: nkind = d.kind;
if (k == nkind.N_FNDECL) {
if (d.lhs != nil) { resolvewalk(c, d.lhs); }; // return type
resolvefnbody(c, d);
} else { if (k == nkind.N_DEF) {
if (d.lhs != nil) { resolvewalk(c, d.lhs); };
if (d.rhs != nil) { resolvewalk(c, d.rhs); };
} else { if (k == nkind.N_TYPEDECL) {
if (d.lhs != nil) { resolvewalk(c, d.lhs); };
} else { if (k == nkind.N_LET) {
if (d.lhs != nil) { resolvewalk(c, d.lhs); };
if (d.rhs != nil) { resolvewalk(c, d.rhs); };
};};};};
d = d.next;
};
let empty: str;
c.curmod = empty;
};