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authorBjörn Gustavsson <[email protected]>2018-11-21 05:55:12 +0100
committerBjörn Gustavsson <[email protected]>2018-11-21 06:10:16 +0100
commitdf0ce3328e4ac64c0bd82fb10a879d4f0732b261 (patch)
treec94dcb451c6ce1490641a70a5d41fa0b411e804e
parentc0812d51fbb550d4a53df128e4ec322746f015ca (diff)
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Fix inadvertently suppressed warning for unused variable
An external fun could inadvertently suppress warnings for unused variables, such as in this example: bug() -> BugVar = foo(), if true -> fun m:f/1 end. There would be no warning that `BugVar` was unused. The bug was introduced in ff432e262e652, which was the commit that extended external funs to allow variables. https://bugs.erlang.org/browse/ERL-762
-rw-r--r--lib/stdlib/src/erl_lint.erl3
-rw-r--r--lib/stdlib/test/erl_lint_SUITE.erl20
2 files changed, 19 insertions, 4 deletions
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index e9ac2fcdff..e0cd68617b 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -2262,8 +2262,7 @@ expr({'fun',Line,Body}, Vt, St) ->
{[],St};
{function,M,F,A} ->
%% New in R15.
- {Bvt, St1} = expr_list([M,F,A], Vt, St),
- {vtupdate(Bvt, Vt),St1}
+ expr_list([M,F,A], Vt, St)
end;
expr({named_fun,_,'_',Cs}, Vt, St) ->
fun_clauses(Cs, Vt, St);
diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl
index f9ab83a120..d18c7c255c 100644
--- a/lib/stdlib/test/erl_lint_SUITE.erl
+++ b/lib/stdlib/test/erl_lint_SUITE.erl
@@ -67,7 +67,8 @@
record_errors/1, otp_11879_cont/1,
non_latin1_module/1, otp_14323/1,
stacktrace_syntax/1,
- otp_14285/1, otp_14378/1]).
+ otp_14285/1, otp_14378/1,
+ external_funs/1]).
suite() ->
[{ct_hooks,[ts_install_cth]},
@@ -88,7 +89,7 @@ all() ->
maps, maps_type, maps_parallel_match,
otp_11851, otp_11879, otp_13230,
record_errors, otp_11879_cont, non_latin1_module, otp_14323,
- stacktrace_syntax, otp_14285, otp_14378].
+ stacktrace_syntax, otp_14285, otp_14378, external_funs].
groups() ->
[{unused_vars_warn, [],
@@ -4134,6 +4135,21 @@ otp_14285(Config) ->
run(Config, Ts),
ok.
+external_funs(Config) when is_list(Config) ->
+ Ts = [{external_funs_1,
+ %% ERL-762: Unused variable warning not being emitted.
+ <<"f() ->
+ BugVar = process_info(self()),
+ if true -> fun m:f/1 end.
+ f(M, F) ->
+ BugVar = process_info(self()),
+ if true -> fun M:F/1 end.">>,
+ [],
+ {warnings,[{2,erl_lint,{unused_var,'BugVar'}},
+ {5,erl_lint,{unused_var,'BugVar'}}]}}],
+ run(Config, Ts),
+ ok.
+
format_error(E) ->
lists:flatten(erl_lint:format_error(E)).