w6c+selfhost: same-module preference for bare-leaf lookup

selfhost/cmd/w6c/main.combined.ww

@@ -4647,6 +4647,48 @@ export fn scopelookupinmodule(s: *scope, mod: str, name: str) *sym = {
 	return nil;
 };
 
+// scopelookupprefer — bare-leaf lookup with same-module preference.
+//
+// Walks the same FNV bucket + hashnext chain + parent walk scopelookup
+// uses. Within each scope's bucket: Pass 1 prefers entries whose
+// `sym.mod` matches `mod`; Pass 2 falls back to the first match
+// regardless of mod (same semantics as scopelookup). We only descend
+// to the parent scope when the current scope has no matching entry at
+// all — so a local binding in a closer scope still shadows a same-name
+// fn from a parent scope, even when the parent entry mod-matches.
+//
+// When `mod` is empty we just call scopelookup — there's no module
+// identity to prefer.
+//
+// Used at bare-leaf lookup sites inside a known current module so that
+// a bare `read` inside lib/os resolves to os.read rather than the
+// io.read that happens to hash earlier into the flat scope. Mirrors
+// cmd/wcc/sym.c scope_lookup_prefer.
+export fn scopelookupprefer(s: *scope, mod: str, name: str) *sym = {
+	if (mod.len == 0) { return scopelookup(s, name); };
+	let p: *scope = s;
+	for (p != nil) {
+		let h: u64 = hashstr(name);
+		let bi: i32 = (h % (p.nbuckets: u64)): i32;
+		let b: *sym = p.buckets[bi];
+		let fallback: *sym = nil;
+		for (b != nil) {
+			if (streq(b.name, name)) {
+				if (b.mod.len > 0) {
+					if (streq(b.mod, mod)) {
+						return b;
+					};
+				};
+				if (fallback == nil) { fallback = b; };
+			};
+			b = b.hashnext;
+		};
+		if (fallback != nil) { return fallback; };
+		p = p.parent;
+	};
+	return nil;
+};
+
 export fn scopedefine(s: *scope, name: str, k: skind, t: *tinfo, decl: *node) *sym = {
 	let empty: str;
 	return scopedefineinmodule(s, name, empty, k, t, decl);
@@ -4725,6 +4767,10 @@ type checker = struct {
 	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.
 };
 
 // seedprimitives — install the built-in type names so `i32`, `str`,
@@ -4823,7 +4869,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_IDENT) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			let s: *sym = scopelookupprefer(c.cur, c.curmod, nm);
 			if (s == nil) {
 				c.nunresolved += 1;
 				if (c.verbose != 0) {
@@ -4838,7 +4884,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_TNAME) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			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
@@ -5637,6 +5683,8 @@ export fn checkinit(c: *checker, a: *arena, tc: *tctx) void = {
 	c.errs = 0;
 	c.verbose = 0;
 	c.fnret = nil;
+	let empty: str;
+	c.curmod = empty;
 	seedprimitives(c);
 };
 
@@ -5652,8 +5700,12 @@ export fn checkfile(c: *checker, file: *node) void = {
 	};
 
 	// 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
@@ -5669,6 +5721,8 @@ export fn checkfile(c: *checker, file: *node) void = {
 		};};};};
 		d = d.next;
 	};
+	let empty: str;
+	c.curmod = empty;
 
 };
 

selfhost/cmd/wcc/check.ww

@@ -31,6 +31,10 @@ type checker = struct {
 	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.
 };
 
 // seedprimitives — install the built-in type names so `i32`, `str`,
@@ -129,7 +133,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_IDENT) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			let s: *sym = scopelookupprefer(c.cur, c.curmod, nm);
 			if (s == nil) {
 				c.nunresolved += 1;
 				if (c.verbose != 0) {
@@ -144,7 +148,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_TNAME) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			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
@@ -943,6 +947,8 @@ export fn checkinit(c: *checker, a: *arena, tc: *tctx) void = {
 	c.errs = 0;
 	c.verbose = 0;
 	c.fnret = nil;
+	let empty: str;
+	c.curmod = empty;
 	seedprimitives(c);
 };
 
@@ -958,8 +964,12 @@ export fn checkfile(c: *checker, file: *node) void = {
 	};
 
 	// 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
@@ -975,5 +985,7 @@ export fn checkfile(c: *checker, file: *node) void = {
 		};};};};
 		d = d.next;
 	};
+	let empty: str;
+	c.curmod = empty;
 
 };

selfhost/cmd/wwdump/main.combined.ww

@@ -4647,6 +4647,48 @@ export fn scopelookupinmodule(s: *scope, mod: str, name: str) *sym = {
 	return nil;
 };
 
+// scopelookupprefer — bare-leaf lookup with same-module preference.
+//
+// Walks the same FNV bucket + hashnext chain + parent walk scopelookup
+// uses. Within each scope's bucket: Pass 1 prefers entries whose
+// `sym.mod` matches `mod`; Pass 2 falls back to the first match
+// regardless of mod (same semantics as scopelookup). We only descend
+// to the parent scope when the current scope has no matching entry at
+// all — so a local binding in a closer scope still shadows a same-name
+// fn from a parent scope, even when the parent entry mod-matches.
+//
+// When `mod` is empty we just call scopelookup — there's no module
+// identity to prefer.
+//
+// Used at bare-leaf lookup sites inside a known current module so that
+// a bare `read` inside lib/os resolves to os.read rather than the
+// io.read that happens to hash earlier into the flat scope. Mirrors
+// cmd/wcc/sym.c scope_lookup_prefer.
+export fn scopelookupprefer(s: *scope, mod: str, name: str) *sym = {
+	if (mod.len == 0) { return scopelookup(s, name); };
+	let p: *scope = s;
+	for (p != nil) {
+		let h: u64 = hashstr(name);
+		let bi: i32 = (h % (p.nbuckets: u64)): i32;
+		let b: *sym = p.buckets[bi];
+		let fallback: *sym = nil;
+		for (b != nil) {
+			if (streq(b.name, name)) {
+				if (b.mod.len > 0) {
+					if (streq(b.mod, mod)) {
+						return b;
+					};
+				};
+				if (fallback == nil) { fallback = b; };
+			};
+			b = b.hashnext;
+		};
+		if (fallback != nil) { return fallback; };
+		p = p.parent;
+	};
+	return nil;
+};
+
 export fn scopedefine(s: *scope, name: str, k: skind, t: *tinfo, decl: *node) *sym = {
 	let empty: str;
 	return scopedefineinmodule(s, name, empty, k, t, decl);
@@ -4725,6 +4767,10 @@ type checker = struct {
 	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.
 };
 
 // seedprimitives — install the built-in type names so `i32`, `str`,
@@ -4823,7 +4869,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_IDENT) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			let s: *sym = scopelookupprefer(c.cur, c.curmod, nm);
 			if (s == nil) {
 				c.nunresolved += 1;
 				if (c.verbose != 0) {
@@ -4838,7 +4884,7 @@ fn resolvewalk(c: *checker, n: *node) void = {
 	if (k == nkind.N_TNAME) {
 		let nm: str = n.str;
 		if (nm.len > 0) {
-			let s: *sym = scopelookup(c.cur, nm);
+			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
@@ -5637,6 +5683,8 @@ export fn checkinit(c: *checker, a: *arena, tc: *tctx) void = {
 	c.errs = 0;
 	c.verbose = 0;
 	c.fnret = nil;
+	let empty: str;
+	c.curmod = empty;
 	seedprimitives(c);
 };
 
@@ -5652,8 +5700,12 @@ export fn checkfile(c: *checker, file: *node) void = {
 	};
 
 	// 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
@@ -5669,6 +5721,8 @@ export fn checkfile(c: *checker, file: *node) void = {
 		};};};};
 		d = d.next;
 	};
+	let empty: str;
+	c.curmod = empty;
 
 };