feat(lang): 0.S - a reference out of a read-only state is read-only (named so), a program's type named like the runtime's is refused (PadButton), tests for both, the migrate case covers lets; changeset

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

selfhost/check/check_state.ludic

@@ -81,6 +81,10 @@ function ck_write_check(t: Node, what: pointer) -> void {
       mg_need(g_mg_cur, mg_state_named(ck_ro_st[li]), true)   # 0.S2: it becomes `mut`
       return
     }
+    if ck_is_ro(li) and li < len(ck_ro_st) and ck_ro_st[li] != null and not (ck_ro_st[li] == ck_tys[li]) {
+      ck_err("state", t, `{what}: {r.s} holds part of a read-only {ck_ro_st[li]}; take the state as mut {ck_ro_st[li]} to change it`)
+      return
+    }
     if ck_is_ro(li) {
       ck_err("state", t, `{what}: {r.s} is read-only here ({r.s}: {ck_tys[li]}); take it as {r.s}: mut {ck_tys[li]} to change it`)
     }

selfhost/check/check_stmt.ludic

@@ -208,9 +208,29 @@ function ck_runtime_shadows() -> void {
       let u = ck_fn(d.s)
       if u != null and u != d { ck_err("shadow", u, `{d.s} is also a function of the engine runtime ({d.file}); choose another name`) }
     }
+    # a type the runtime declares - `property PadButton` beside its `enum PadButton` compiled,
+    # and the two layouts met in the IR
+    if ck_type_kind(d) != "" {
+      var k = 0
+      while k < g_prog_user_end and k < len(prog) {
+        let o = prog[k]
+        if ck_type_kind(o) != "" and (o.s == d.s) {
+          ck_err("shadow", o, `{d.s} is the runtime's {ck_type_kind(d)} ({d.file}); choose another name for this {ck_type_kind(o)}`)
+        }
+        k += 1
+      }
+    }
     r += 1
   }
 }
+function ck_type_kind(d: Node) -> pointer {
+  if d.kind == N_ENUM { return "enum" }
+  if d.kind == N_COMP and d.uns == 2 { return "state" }
+  if d.kind == N_COMP { return "property" }
+  if d.kind == N_STRUCT { return "record" }
+  if d.kind == N_EVENT { return "event" }
+  return ""
+}
 function ck_hooks(hs: []Node) -> void {
   var i = 0
   while i < len(hs) {