Merge branch 'bjorn/compiler/map-fixes'

* bjorn/compiler/map-fixes:
  cerl: Remove a clause in fold_map_pairs/3 that will never be reached
  Move grouping of map constructions from v3_core to v3_kernel
  core_pp: Correct printing of map literals
  Strengthen and modernize compile_SUITE
  core_parse: Always fold literal conses
  cerl: Make sure that we preserve the invariants for maps
  cerl_clauses: Fix indentation
  sys_core_fold: Strengthen optimization of letrecs in effect context
  Fix handling of binary map keys in comprehensions
  core_lib: Teach is_var_used/2 to handle keys in map patterns
  warnings_SUITE: Eliminate compiler warning for a shadowed variable
  lc_SUITE: Add shadow/1
  Modernize lc_SUITE

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/compiler/test/map_SUITE.erl b/lib/compiler/test/map_SUITE.erl
index dbac61765b..bc5ae803c6 100644
--- a/lib/compiler/test/map_SUITE.erl
+++ b/lib/compiler/test/map_SUITE.erl
@@ -319,6 +319,12 @@ t_update_exact(Config) when is_list(Config) ->
     {'EXIT',{badarg,_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
     {'EXIT',{badarg,_}} = (catch <<>>#{nonexisting:=val}),
     {'EXIT',{badarg,_}} = (catch M0#{<<0:257>> := val}), %% limitation
+
+    %% A workaround for a bug allowed an empty map to be updated.
+    {'EXIT',{badarg,_}} = (catch (id(#{}))#{a:=1}),
+    {'EXIT',{badarg,_}} = (catch #{}#{a:=1}),
+    Empty = #{},
+    {'EXIT',{badarg,_}} = (catch Empty#{a:=1}),
     ok.
 
 t_update_values(Config) when is_list(Config) ->