lua: parenthesized expressions truncate multi-return via new lua-paren AST node +2 tests

lib/lua/test.sh

@@ -958,6 +958,12 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 1870)
 (eval "(lua-eval-ast \"local a = {x=0} function a:add(x) self.x = self.x+x return self end return a:add(10):add(20):add(30).x\")")
 
+;; ── Parenthesized expression truncates multi-return ──────────
+(epoch 1880)
+(eval "(lua-eval-ast \"local function f() return 1, 2, 3 end local a, b, c = (f()) return (a == 1 and b == nil and c == nil) and 1 or 0\")")
+(epoch 1881)
+(eval "(lua-eval-ast \"local function f() return 10, 20 end return (f()) + 1\")")
+
 EPOCHS
 
 OUTPUT=$(timeout 60 "$SX_SERVER" < "$TMPFILE" 2>/dev/null)
@@ -1077,7 +1083,7 @@ check 213 "parse and/or prec"               '(lua-binop "or" (lua-binop "and"'
 check 214 "parse =="                        '(lua-binop "==" (lua-name "a") (lua-name "b"))'
 check 215 "parse .. right-assoc"            '(lua-binop ".." (lua-name "a") (lua-binop ".."'
 check 216 "parse ^ right-assoc"             '(lua-binop "^" (lua-name "a") (lua-binop "^"'
-check 217 "parse paren override"            '(lua-binop "*" (lua-binop "+"'
+check 217 "parse paren override"            '(lua-binop "*" (lua-paren (lua-binop "+"'
 
 check 220 "parse -x"                        '(lua-unop "-" (lua-name "x"))'
 check 221 "parse not x"                     '(lua-unop "not" (lua-name "x"))'
@@ -1450,6 +1456,10 @@ check 1863 "break in repeat"                '3'
 # ── Method-call chaining ─────────────────────────────────────
 check 1870 "a:add():add():add().x chain"    '60'
 
+# ── Parenthesized truncates multi-return ─────────────────────
+check 1880 "(f()) scalar coerce"            '1'
+check 1881 "(f()) + 1 scalar"               '11'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL Lua-on-SX tests passed"