escape dot chains that are lua keywords

moonscript/transform.lua

@@ -1271,6 +1271,19 @@ Value = Transformer({
   end,
   chain = function(self, node)
     local stub = node[#node]
+    for i = 3, #node do
+      local part = node[i]
+      if ntype(part) == "dot" and data.lua_keywords[part[2]] then
+        node[i] = {
+          "index",
+          {
+            "string",
+            '"',
+            part[2]
+          }
+        }
+      end
+    end
     if ntype(node[2]) == "string" then
       node[2] = {
         "parens",

moonscript/transform.moon

@@ -680,6 +680,12 @@ Value = Transformer {
   chain: (node) =>
     stub = node[#node]
 
+    -- escape lua keywords used in dot accessors
+    for i=3,#node
+      part = node[i]
+      if ntype(part) == "dot" and data.lua_keywords[part[2]]
+        node[i] = { "index", {"string", '"', part[2]} }
+
     if ntype(node[2]) == "string"
       -- add parens if callee is raw string
       node[2] = {"parens", node[2] }

tests/inputs/syntax.moon

@@ -227,4 +227,9 @@ a *= 3 + 5
 a *= 3
 a /= func "cool"
 
+---
+
+x.then = "hello"
+x.while.true = "hello"
+
 -- cooool

tests/outputs/syntax.lua

@@ -227,3 +227,5 @@ a = a + (3 - 5)
 a = a * (3 + 5)
 a = a * 3
 a = a / func("cool")
+x["then"] = "hello"
+x["while"]["true"] = "hello"