compiler,stdlib: Fix Map literals as keys for Maps in patterns

5 files changed, 26 insertions, 23 deletions

diff --git a/lib/compiler/src/cerl.erl b/lib/compiler/src/cerl.erl
index ed11c8de4d..54eac20ac4 100644
--- a/lib/compiler/src/cerl.erl
+++ b/lib/compiler/src/cerl.erl
@@ -133,7 +133,7 @@
      ]).
 
 -export_type([c_binary/0, c_bitstr/0, c_call/0, c_clause/0, c_cons/0, c_fun/0,
-	      c_literal/0, c_map_pair/0, c_module/0, c_tuple/0,
+	      c_literal/0, c_map/0, c_map_pair/0, c_module/0, c_tuple/0,
 	      c_values/0, c_var/0, cerl/0, var_name/0]).
 
 -include("core_parse.hrl").
diff --git a/lib/compiler/src/core_lib.erl b/lib/compiler/src/core_lib.erl
index 93ec3bbad5..2792fd8fa5 100644
--- a/lib/compiler/src/core_lib.erl
+++ b/lib/compiler/src/core_lib.erl
@@ -59,7 +59,7 @@ is_lit_bin(Es) ->
 
 %% Return the value of LitExpr.
 -spec literal_value(cerl:c_literal() | cerl:c_binary() |
-		    cerl:c_cons() | cerl:c_tuple()) -> term().
+		    cerl:c_map() | cerl:c_cons() | cerl:c_tuple()) -> term().
 
 literal_value(#c_literal{val=V}) -> V;
 literal_value(#c_binary{segments=Es}) ->
@@ -67,7 +67,14 @@ literal_value(#c_binary{segments=Es}) ->
 literal_value(#c_cons{hd=H,tl=T}) ->
     [literal_value(H)|literal_value(T)];
 literal_value(#c_tuple{es=Es}) ->
-    list_to_tuple(literal_value_list(Es)).
+    list_to_tuple(literal_value_list(Es));
+literal_value(#c_map{arg=Cm,es=Cmps}) ->
+    M = literal_value(Cm),
+    lists:foldl(fun(#c_map_pair{ key=Ck, val=Cv },Mi) ->
+		K = literal_value(Ck),
+		V = literal_value(Cv),
+		maps:put(K,V,Mi)
+	end, M, Cmps).
 
 literal_value_list(Vals) -> [literal_value(V) || V <- Vals].
 
diff --git a/lib/compiler/src/sys_pre_expand.erl b/lib/compiler/src/sys_pre_expand.erl
index 91a46a20fe..761ae8409c 100644
--- a/lib/compiler/src/sys_pre_expand.erl
+++ b/lib/compiler/src/sys_pre_expand.erl
@@ -232,7 +232,7 @@ pattern({map,Line,Ps}, St0) ->
     {TPs,St1} = pattern_list(Ps, St0),
     {{map,Line,TPs},St1};
 pattern({map_field_exact,Line,K0,V0}, St0) ->
-    {K,St1} = pattern(K0, St0),
+    {K,St1} = expr(K0, St0),
     {V,St2} = pattern(V0, St1),
     {{map_field_exact,Line,K,V},St2};
 %%pattern({struct,Line,Tag,Ps}, St0) ->
diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index a548ba2f7c..8c18f6a9f7 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -1605,26 +1605,17 @@ pattern_alias_map_pair_patterns([Cv1,Cv2|Cvs]) ->
     pattern_alias_map_pair_patterns([pat_alias(Cv1,Cv2)|Cvs]).
 
 pattern_map_pair({map_field_exact,L,K,V}, St) ->
-    %% FIXME: Better way to construct literals? or missing case
-    %% {Key,_,_} = expr(K, St),
-    Key = case K of
-	{bin,L,Es0} ->
-	    case constant_bin(Es0) of
-		error ->
-		    %% this will throw a cryptic error message
-		    %% but it is better than nothing
-		    throw(nomatch);
-		Bin ->
-		    #c_literal{anno=lineno_anno(L,St),val=Bin}
-	    end;
+    case expr(K,St) of
+	{#c_literal{}=Key,_,_} ->
+	    #c_map_pair{anno=lineno_anno(L, St),
+			op=#c_literal{val=exact},
+			key=Key,
+			val=pattern(V, St)};
 	_ ->
-	    pattern(K,St)
-    end,
-    #c_map_pair{anno=lineno_anno(L, St),
-                op=#c_literal{val=exact},
-		key=Key,
-		val=pattern(V, St)}.
-
+	    %% this will throw a cryptic error message
+	    %% but it is better than nothing
+	    throw(nomatch)
+    end.
 
 %% pat_bin([BinElement], State) -> [BinSeg].
 
diff --git a/lib/compiler/test/map_SUITE.erl b/lib/compiler/test/map_SUITE.erl
index cc018e4305..403b7e8405 100644
--- a/lib/compiler/test/map_SUITE.erl
+++ b/lib/compiler/test/map_SUITE.erl
@@ -113,6 +113,10 @@ t_build_and_match_literals(Config) when is_list(Config) ->
     M = #{ map_1:=#{ map_2:=#{value_3 := third}, value_2:= second}, value_1:=first} =
 	 id(#{ map_1=>#{ map_2=>#{value_3 => third}, value_2=> second}, value_1=>first}),
 
+    %% map key
+    #{ #{} := 42 } = id(#{ #{} => 42 }),
+    #{ #{ "a" => 3 } := 42 } = id(#{ #{ "a" => 3} => 42 }),
+
     %% nil key
     #{[]:=ok,1:=2} = id(#{[]=>ok,1=>2}),
 
@@ -123,6 +127,7 @@ t_build_and_match_literals(Config) when is_list(Config) ->
     {'EXIT',{{badmatch,_},_}} = (catch (#{x:=3} = id(#{y=>3}))),
     {'EXIT',{{badmatch,_},_}} = (catch (#{x:=3} = id(#{x=>"three"}))),
     {'EXIT',{badarg,_}} = (catch id(#{<<0:258>> =>"three"})),
+    {'EXIT',{{badmatch,_},_}} = (catch (#{#{"a"=>42} := 3}=id(#{#{"a"=>3}=>42}))),
     ok.
 
 t_build_and_match_aliasing(Config) when is_list(Config) ->