Narrow TypeGuard/TypeIs subjects bound by keyword argument

debug_probe.py

@@ -0,0 +1,38 @@
+
+p = r'/home/evin/pyrefly/pyrefly/lib/alt/narrow.rs'
+s = open(p, 'rb').read()
+nl = b'\r\n' if s.count(b'\r\n') > s.count(b'\n') // 2 else b'\n'
+old = nl.join([
+    b'        // Cheaply reject callees that cannot produce a `TypeGuard`/`TypeIs` result before',
+    b'        // paying for full call resolution.',
+    b'        if !func_ty.is_typeis() && !func_ty.is_typeguard() {',
+    b'            return None;',
+    b'        }',
+    b'        let CallTargetLookup::Ok(call_target) = self.as_call_target(func_ty.clone()) else {',
+    b'            return None;',
+    b'        };'])
+new = nl.join([
+    b'        eprintln!("DBG resolve: func_ty={} typeis={} typeguard={}", self.for_display(func_ty.clone()), func_ty.is_typeis(), func_ty.is_typeguard());',
+    b'        // Cheaply reject callees that cannot produce a `TypeGuard`/`TypeIs` result before',
+    b'        // paying for full call resolution.',
+    b'        if !func_ty.is_typeis() && !func_ty.is_typeguard() {',
+    b'            eprintln!("DBG resolve: cheap-reject");',
+    b'            return None;',
+    b'        }',
+    b'        let CallTargetLookup::Ok(call_target) = self.as_call_target(func_ty.clone()) else {',
+    b'            eprintln!("DBG resolve: no call target");',
+    b'            return None;',
+    b'        };'])
+assert s.count(old) == 1, s.count(old)
+s = s.replace(old, new)
+old2 = nl.join([
+    b'        match outcome.ty {',
+    b'            Type::TypeIs(narrowed) => {'])
+new2 = nl.join([
+    b'        eprintln!("DBG resolve: outcome-ty={} subject={:?}", self.for_display(outcome.ty.clone()), outcome.guard_subject);',
+    b'        match outcome.ty {',
+    b'            Type::TypeIs(narrowed) => {'])
+assert s.count(old2) == 1
+s = s.replace(old2, new2)
+open(p, 'wb').write(s)
+print('debug probes inserted')