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-rw-r--r--lib/compiler/src/sys_core_fold.erl24
1 files changed, 17 insertions, 7 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index b78507c47e..e134a37f22 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -277,7 +277,7 @@ expr(#c_fun{}=Fun, effect, _) ->
add_warning(Fun, useless_building),
void();
expr(#c_fun{vars=Vs0,body=B0}=Fun, Ctxt0, Sub0) ->
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
Ctxt = case Ctxt0 of
{letrec,Ctxt1} -> Ctxt1;
value -> value
@@ -420,13 +420,13 @@ expr(#c_try{anno=A,arg=E0,vars=Vs0,body=B0,evars=Evs0,handler=H0}=Try, _, Sub0)
%% Here is the general try/catch construct outside of guards.
%% We can remove try if the value is simple and replace it with a let.
E1 = body(E0, value, Sub0),
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
B1 = body(B0, value, Sub1),
case is_safe_simple(E1, Sub0) of
true ->
expr(#c_let{anno=A,vars=Vs1,arg=E1,body=B1}, value, Sub0);
false ->
- {Evs1,Sub2} = pattern_list(Evs0, Sub0),
+ {Evs1,Sub2} = var_list(Evs0, Sub0),
H1 = body(H0, value, Sub2),
Try#c_try{arg=E1,vars=Vs1,body=B1,evars=Evs1,handler=H1}
end.
@@ -1124,7 +1124,7 @@ clause(#c_clause{pats=Ps0,guard=G0,body=B0}=Cl, Cexpr, Ctxt, Sub0) ->
%% the unsubstituted variables and values.
let_substs(Vs0, As0, Sub0) ->
- {Vs1,Sub1} = pattern_list(Vs0, Sub0),
+ {Vs1,Sub1} = var_list(Vs0, Sub0),
{Vs2,As1,Ss} = let_substs_1(Vs1, As0, Sub1),
Sub2 = sub_add_scope([V || #c_var{name=V} <- Vs2], Sub1),
{Vs2,As1,
@@ -1224,6 +1224,16 @@ pattern_list(Ps, Sub) -> pattern_list(Ps, Sub, Sub).
pattern_list(Ps0, Isub, Osub0) ->
mapfoldl(fun (P, Osub) -> pattern(P, Isub, Osub) end, Osub0, Ps0).
+%% var_list([Var], InSub) -> {Pattern,OutSub}.
+%% Works like pattern_list/2 but only accept variables and is
+%% guaranteed not to throw an exception.
+
+var_list(Vs, Sub0) ->
+ mapfoldl(fun (#c_var{}=V, Sub) ->
+ pattern(V, Sub, Sub)
+ end, Sub0, Vs).
+
+
%% is_subst(Expr) -> true | false.
%% Test whether an expression is a suitable substitution.
@@ -2255,11 +2265,11 @@ move_let_into_expr(#c_let{vars=InnerVs0,body=InnerBody0}=Inner,
%%
Arg = body(Arg0, Sub0),
ScopeSub0 = sub_subst_scope(Sub0#sub{t=#{}}),
- {OuterVs,ScopeSub} = pattern_list(OuterVs0, ScopeSub0),
+ {OuterVs,ScopeSub} = var_list(OuterVs0, ScopeSub0),
OuterBody = body(OuterBody0, ScopeSub),
- {InnerVs,Sub} = pattern_list(InnerVs0, Sub0),
+ {InnerVs,Sub} = var_list(InnerVs0, Sub0),
InnerBody = body(InnerBody0, Sub),
Outer#c_let{vars=OuterVs,arg=Arg,
body=Inner#c_let{vars=InnerVs,arg=OuterBody,body=InnerBody}};
@@ -2599,7 +2609,7 @@ move_case_into_arg(#c_case{arg=#c_let{vars=OuterVars0,arg=OuterArg,
%% in case <InnerArg> of <InnerClauses> end
%%
ScopeSub0 = sub_subst_scope(Sub#sub{t=#{}}),
- {OuterVars,ScopeSub} = pattern_list(OuterVars0, ScopeSub0),
+ {OuterVars,ScopeSub} = var_list(OuterVars0, ScopeSub0),
InnerArg = body(InnerArg0, ScopeSub),
Outer#c_let{vars=OuterVars,arg=OuterArg,
body=Inner#c_case{arg=InnerArg,clauses=InnerClauses}};