stdlib: Fix map comprehension result when a key value is replaced

Fix #9358
erlang · Jan 30, 2025 · aac7149 · aac7149
1 parent 05886b9
commit aac7149
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diff --git a/lib/stdlib/src/erl_eval.erl b/lib/stdlib/src/erl_eval.erl
@@ -970,7 +970,7 @@ eval_bc1(E, [], Bs, Lf, Ef, FUVs, Acc) ->
 
 eval_mc(E, Qs, Bs, Lf, Ef, RBs, FUVs) ->
     L = eval_mc1(E, Qs, Bs, Lf, Ef, FUVs, []),
-    Map = maps:from_list(L),
+    Map = maps:from_list(reverse(L)),
     ret_expr(Map, Bs, RBs).
 
 eval_mc1(E, [Q|Qs], Bs0, Lf, Ef, FUVs, Acc0) ->

diff --git a/lib/stdlib/test/erl_eval_SUITE.erl b/lib/stdlib/test/erl_eval_SUITE.erl
@@ -1795,7 +1795,12 @@ eep43(Config) when is_list(Config) ->
 	  "    (fun(#{X := value}) -> true end)(#{X => value}) "
 	  "end.",
 	  true),
-
+    check(fun() -> #{A => B || {A, B} <- [{1, 2}, {1, 3}]} end,
+          "#{A => B || {A, B} <- [{1, 2}, {1, 3}]}.",
+	  #{1 => 3}),
+    check(fun() -> #{A => B || X <- [1, 5], {A, B} <- [{X, X+1}, {X, X+3}]} end,
+          "#{A => B || X <- [1, 5], {A, B} <- [{X, X+1}, {X, X+3}]}.",
+	  #{1 => 4,5 => 8}),
     error_check("[camembert]#{}.", {badmap,[camembert]}),
     error_check("[camembert]#{nonexisting:=v}.", {badmap,[camembert]}),
     error_check("#{} = 1.", {badmatch,1}),