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

test/wcc/data/samemodprefer/mod1/mod1.ww

@@ -0,0 +1,18 @@
+// samemodprefer/mod1 — exports a `read` that takes an i32 plus a
+// `caller` that invokes bare `read(1i32)`. The bare-leaf lookup must
+// resolve to mod1.read (i32 → i32) rather than mod2.read (str → i32),
+// which coexists in the flat scope. Pre-fix the lookup picked
+// whichever entry hashed earliest into the bucket; a wrong bind would
+// surface as a check-time signature mismatch. Paired with mod2/mod2.ww
+// and test/wcc/697_samemod_prefer.c.
+
+export fn read(x: i32) i32 = {
+	return x + 100i32;
+};
+
+export fn caller() i32 = {
+	// Bare-leaf call inside mod1: must bind to mod1.read (i32 arg).
+	// If preference doesn't kick in this fails check: mod2.read
+	// expects a str, so `read(1i32)` would be a signature mismatch.
+	return read(1i32);
+};

test/wcc/data/samemodprefer/mod2/mod2.ww

@@ -0,0 +1,18 @@
+// samemodprefer/mod2 — exports a `read` that takes a str plus a
+// `caller` that invokes bare `read("ok")`. The bare-leaf lookup must
+// resolve to mod2.read (str → i32) rather than mod1.read (i32 → i32),
+// which coexists in the flat scope. Pre-fix the lookup picked
+// whichever entry hashed earliest into the bucket; a wrong bind would
+// surface as a check-time signature mismatch. Paired with mod1/mod1.ww
+// and test/wcc/697_samemod_prefer.c.
+
+export fn read(x: str) i32 = {
+	return x.len + 200i32;
+};
+
+export fn caller() i32 = {
+	// Bare-leaf call inside mod2: must bind to mod2.read (str arg).
+	// If preference doesn't kick in this fails check: mod1.read
+	// expects an i32, so `read("ok")` would be a signature mismatch.
+	return read("ok");
+};

test/wcc/data/samemodprefer/pos.ww

@@ -0,0 +1,20 @@
+// Positive case: two modules each export `read` with DIFFERENT
+// signatures (mod1: i32 → i32, mod2: str → i32). Each module also
+// exports a `caller` that invokes bare `read(...)` with its own arg
+// type. The bare-leaf inside mod1 must bind to mod1.read; inside mod2
+// to mod2.read. If preference doesn't kick in and the bare lookup
+// picks the other module's `read`, the build fails with a signature
+// mismatch at check-time. The driver test asserts that this fixture
+// builds successfully.
+//
+// We don't assert runtime exit codes here because cgen still emits
+// unmangled `TEXT read` labels for both modules and the linker
+// collapses them — that's a separate codegen sweep, orthogonal to the
+// resolver fix this test pins.
+
+use mod1;
+use mod2;
+
+fn main() i32 = {
+	return 0i32;
+};