Correctly Macro.escape :quote triplet without meta (#13594)

Closes #13593.

Author: kristofka

lib/elixir/src/elixir_quote.erl

@@ -139,7 +139,7 @@ escape(Expr, Op, Unquote) ->
     unquote=Unquote
   }).
 
-do_escape({Left, Meta, Right}, #elixir_quote{op=prune_metadata} = Q) ->
+do_escape({Left, Meta, Right}, #elixir_quote{op=prune_metadata} = Q) when is_list(Meta) ->
   TM = [{K, V} || {K, V} <- Meta, (K == no_parens) orelse (K == line)],
   TL = do_quote(Left, Q),
   TR = do_quote(Right, Q),
@@ -263,7 +263,7 @@ quote(Expr, Q) ->
 
 %% quote/unquote
 
-do_quote({quote, Meta, [Arg]}, Q) ->
+do_quote({quote, Meta, [Arg]}, Q) when is_list(Meta) ->
   TArg = do_quote(Arg, Q#elixir_quote{unquote=false}),
 
   NewMeta = case Q of
@@ -273,7 +273,7 @@ do_quote({quote, Meta, [Arg]}, Q) ->
 
   {'{}', [], [quote, meta(NewMeta, Q), [TArg]]};
 
-do_quote({quote, Meta, [Opts, Arg]}, Q) ->
+do_quote({quote, Meta, [Opts, Arg]}, Q) when is_list(Meta) ->
   TOpts = do_quote(Opts, Q),
   TArg = do_quote(Arg, Q#elixir_quote{unquote=false}),
 
@@ -284,13 +284,13 @@ do_quote({quote, Meta, [Opts, Arg]}, Q) ->
 
   {'{}', [], [quote, meta(NewMeta, Q), [TOpts, TArg]]};
 
-do_quote({unquote, _Meta, [Expr]}, #elixir_quote{unquote=true}) ->
+do_quote({unquote, Meta, [Expr]}, #elixir_quote{unquote=true}) when is_list(Meta) ->
   Expr;
 
 %% Aliases
 
 do_quote({'__aliases__', Meta, [H | T]}, #elixir_quote{aliases_hygiene=(#{}=E)} = Q)
-    when is_atom(H), H /= 'Elixir' ->
+     when is_list(Meta), is_atom(H), H /= 'Elixir' ->
   Annotation =
     case elixir_aliases:expand(Meta, [H | T], E, true) of
       Atom when is_atom(Atom) -> Atom;
@@ -312,16 +312,16 @@ do_quote({Name, Meta, nil}, #elixir_quote{op=add_context} = Q)
 
 %% Unquote
 
-do_quote({{{'.', Meta, [Left, unquote]}, _, [Expr]}, _, Args}, #elixir_quote{unquote=true} = Q) ->
+do_quote({{{'.', Meta, [Left, unquote]}, _, [Expr]}, _, Args}, #elixir_quote{unquote=true} = Q) when is_list(Meta) ->
   do_quote_call(Left, Meta, Expr, Args, Q);
 
-do_quote({{'.', Meta, [Left, unquote]}, _, [Expr]}, #elixir_quote{unquote=true} = Q) ->
+do_quote({{'.', Meta, [Left, unquote]}, _, [Expr]}, #elixir_quote{unquote=true} = Q) when is_list(Meta) ->
   do_quote_call(Left, Meta, Expr, nil, Q);
 
 %% Imports
 
 do_quote({'&', Meta, [{'/', _, [{F, _, C}, A]}] = Args},
-  #elixir_quote{imports_hygiene=(#{}=E)} = Q) when is_atom(F), is_integer(A), is_atom(C) ->
+  #elixir_quote{imports_hygiene=(#{}=E)} = Q) when is_atom(F), is_integer(A), is_atom(C), is_list(Meta) ->
   NewMeta =
     case elixir_dispatch:find_import(Meta, F, A, E) of
       false ->
@@ -571,4 +571,4 @@ annotate_def({'when', Meta, [Left, Right]}, Context) ->
 annotate_def({Fun, Meta, Args}, Context) ->
   {Fun, keystore(context, Meta, Context), Args};
 annotate_def(Other, _Context) ->
-  Other.
+  Other.

lib/elixir/test/elixir/macro_test.exs

@@ -36,6 +36,10 @@ defmodule MacroTest do
       assert Macro.escape({:a}) == {:{}, [], [:a]}
       assert Macro.escape({:a, :b, :c}) == {:{}, [], [:a, :b, :c]}
       assert Macro.escape({:a, {1, 2, 3}, :c}) == {:{}, [], [:a, {:{}, [], [1, 2, 3]}, :c]}
+
+      # False positives
+      assert Macro.escape({:quote, :foo, [:bar]}) == {:{}, [], [:quote, :foo, [:bar]]}
+      assert Macro.escape({:quote, :foo, [:bar, :baz]}) == {:{}, [], [:quote, :foo, [:bar, :baz]]}
     end
 
     test "escapes maps" do