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authorBjörn Gustavsson <[email protected]>2016-08-15 15:34:06 +0200
committerBjörn Gustavsson <[email protected]>2016-09-02 14:24:36 +0200
commit0baa07cdf2754748bbc2d969bf83f08c0976fb78 (patch)
treeb5d649dbe4778d8488ae09a99e68435adc216342 /lib/stdlib/src/erl_expand_records.erl
parent8a04dd4dd2d479efe488b0bed118e10559835fb6 (diff)
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Fix overridden BIFs
The filters in a list comprehension can be guard expressions or an ordinary expressions. If a guard expression is used as a filter, an exception will basically mean the same as 'false': t() -> L = [{some_tag,42},an_atom], [X || X <- L, element(1, X) =:= some_tag] %% Returns [{some_tag,42}] On the other hand, if an ordinary expression is used as a filter, there will be an exception: my_element(N, T) -> element(N, T). t() -> L = [{some_tag,42},an_atom], [X || X <- L, my_element(1, X) =:= some_tag] %% Causes a 'badarg' exception when element(1, an_atom) is evaluated It has been allowed for several releases to override a BIF with a local function. Thus, if we define a function called element/2, it will be called instead of the BIF element/2 within the module. We must use the "erlang:" prefix to call the BIF. Therefore, the following code is expected to work the same way as in our second example above: -compile({no_auto_import,[element/2]}). element(N, T) -> erlang:element(N, T). t() -> L = [{some_tag,42},an_atom], [X || X <- L, element(1, X) =:= some_tag]. %% Causes a 'badarg' exception when element(1, an_atom) is evaluated But the compiler refuses to compile the code with the following diagnostic: call to local/imported function element/2 is illegal in guard
Diffstat (limited to 'lib/stdlib/src/erl_expand_records.erl')
-rw-r--r--lib/stdlib/src/erl_expand_records.erl11
1 files changed, 9 insertions, 2 deletions
diff --git a/lib/stdlib/src/erl_expand_records.erl b/lib/stdlib/src/erl_expand_records.erl
index ab47f05320..2280464bff 100644
--- a/lib/stdlib/src/erl_expand_records.erl
+++ b/lib/stdlib/src/erl_expand_records.erl
@@ -507,9 +507,16 @@ lc_tq(Line, [{b_generate,Lg,P0,G0} | Qs0], St0) ->
{P1,St2} = pattern(P0, St1),
{Qs1,St3} = lc_tq(Line, Qs0, St2),
{[{b_generate,Lg,P1,G1} | Qs1],St3};
-lc_tq(Line, [F0 | Qs0], St0) ->
+lc_tq(Line, [F0 | Qs0], #exprec{calltype=Calltype}=St0) ->
%% Allow record/2 and expand out as guard test.
- case erl_lint:is_guard_test(F0) of
+ IsOverriden = fun(FA) ->
+ case Calltype of
+ #{FA := local} -> true;
+ #{FA := {imported,_}} -> true;
+ _ -> false
+ end
+ end,
+ case erl_lint:is_guard_test(F0, [], IsOverriden) of
true ->
{F1,St1} = guard_test(F0, St0),
{Qs1,St2} = lc_tq(Line, Qs0, St1),