Correctly handle non-matching patterns against literal values

The pass sys_core_fold did not correctly handle non-matching patterns in code
such as:

    0 = case <<>> of
            <<>> -> 0;
            a -> 1
        end.

Function case_opt_lit/3 is rewritten in two passes to first remove any
non-matching clause and only then potentially remove the related patterns
in each clause.

Reported-by: Ulf Norell

1 files changed, 12 insertions, 2 deletions

diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl
index 9c986576d5..6a7036d728 100644
--- a/lib/compiler/test/core_fold_SUITE.erl
+++ b/lib/compiler/test/core_fold_SUITE.erl
@@ -23,7 +23,7 @@
 	 t_element/1,setelement/1,t_length/1,append/1,t_apply/1,bifs/1,
 	 eq/1,nested_call_in_case/1,guard_try_catch/1,coverage/1,
 	 unused_multiple_values_error/1,unused_multiple_values/1,
-	 multiple_aliases/1,redundant_boolean_clauses/1]).
+	 multiple_aliases/1,redundant_boolean_clauses/1,mixed_matching_clauses/1]).
 
 -export([foo/0,foo/1,foo/2,foo/3]).
 
@@ -40,7 +40,7 @@ groups() ->
       [t_element,setelement,t_length,append,t_apply,bifs,
        eq,nested_call_in_case,guard_try_catch,coverage,
        unused_multiple_values_error,unused_multiple_values,
-       multiple_aliases,redundant_boolean_clauses]}].
+       multiple_aliases,redundant_boolean_clauses,mixed_matching_clauses]}].
 
 
 init_per_suite(Config) ->
@@ -373,5 +373,15 @@ redundant_boolean_clauses(Config) when is_list(Config) ->
             true -> yes
         end.
 
+mixed_matching_clauses(Config) when is_list(Config) ->
+  0 = case #{} of
+          #{} -> 0;
+          a -> 1
+      end,
+  0 = case <<>> of
+          <<>> -> 0;
+          a -> 1
+      end,
+  ok.
 
 id(I) -> I.