Add a warning for switch cases jumping into variable scopes

PlutoLang · Feb 28, 2024 · a9381a9 · a9381a9
1 parent 333134c
commit a9381a9
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/src/lparser.cpp b/src/lparser.cpp
@@ -2972,6 +2972,8 @@ static void switchimpl (LexState *ls, int tk, void(*caselist)(LexState*,void*),
     }
   }
 
+  const auto nactvar = fs->nactvar;
+
   std::vector<int> first{};
   TString* const begin_switch = luaS_newliteral(ls->L, "pluto_begin_switch");
   TString* default_case = nullptr;
@@ -2991,6 +2993,13 @@ static void switchimpl (LexState *ls, int tk, void(*caselist)(LexState*,void*),
 
   while (gett(ls) != TK_END) {
     auto case_line = ls->getLineNumber();
+    if (fs->nactvar != nactvar) {
+      const char *varname = getstr(getlocalvardesc(ls->fs, nactvar)->vd.name);
+      const char *msg = "switch case on line %d jumps into the scope of local '%s'. this will be a fatal error in 0.9.0.";
+      msg = luaO_pushfstring(ls->L, msg, case_line, varname);
+      throw_warn(ls, msg, WT_DEPRECATED);
+      lua_pop(ls->L, 1);  /* pop result of luaO_pushfstring */
+    }
     if (gett(ls) == TK_DEFAULT) {
       luaX_next(ls); /* Skip 'default' */
       checknext(ls, tk);