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authorPéter Gömöri <[email protected]>2016-10-13 23:02:37 +0200
committerPéter Gömöri <[email protected]>2016-10-13 23:12:32 +0200
commit8db6c68b2d748e4a72445959f205d8d6c4dd18ed (patch)
tree4788407e98b6f886af1cbc720612ffbd4ce16851 /lib/stdlib
parent9c013e2f9f7e32de38dc9640038aee1840d68e04 (diff)
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dbg:fun2ms: allow empty list as head
Running 'dbg:fun2ms(fun([]) -> return_trace() end' resulted in an error "dbg:fun2ms requires fun with single variable or list parameter" But the empty list is actually a list and it is a valid value as a match-spec head (matching on arity-0 functions). Although its practical use is questionable this commit eliminates a small limitation of ms_transform which is not present in the match-spec grammar.
Diffstat (limited to 'lib/stdlib')
-rw-r--r--lib/stdlib/src/ms_transform.erl2
-rw-r--r--lib/stdlib/test/ms_transform_SUITE.erl2
2 files changed, 4 insertions, 0 deletions
diff --git a/lib/stdlib/src/ms_transform.erl b/lib/stdlib/src/ms_transform.erl
index c0eea652e7..98745b13f3 100644
--- a/lib/stdlib/src/ms_transform.erl
+++ b/lib/stdlib/src/ms_transform.erl
@@ -451,6 +451,8 @@ check_type(_,[{record,_,_,_}],ets) ->
ok;
check_type(_,[{cons,_,_,_}],dbg) ->
ok;
+check_type(_,[{nil,_}],dbg) ->
+ ok;
check_type(Line0,[{match,_,{var,_,_},X}],Any) ->
check_type(Line0,[X],Any);
check_type(Line0,[{match,_,X,{var,_,_}}],Any) ->
diff --git a/lib/stdlib/test/ms_transform_SUITE.erl b/lib/stdlib/test/ms_transform_SUITE.erl
index 1c5faa960b..f35013b1b2 100644
--- a/lib/stdlib/test/ms_transform_SUITE.erl
+++ b/lib/stdlib/test/ms_transform_SUITE.erl
@@ -296,6 +296,8 @@ basic_dbg(Config) when is_list(Config) ->
compile_and_run(<<"dbg:fun2ms(fun([A,B]) -> bindings() end)">>),
[{['$1','$2'],[],['$_']}] =
compile_and_run(<<"dbg:fun2ms(fun([A,B]) -> object() end)">>),
+ [{[],[],[{return_trace}]}] =
+ compile_and_run(<<"dbg:fun2ms(fun([]) -> return_trace() end)">>),
ok.
%% Test calling of ets/dbg:fun2ms from the shell.