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fix(es/optimization): Don't create invalid sequence expressions (#4285)

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Donny/강동윤 2022-04-09 03:08:31 +09:00 committed by GitHub
parent 6c50ae6b0d
commit 4868c73d5b
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2 changed files with 42 additions and 1 deletions
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25
crates/swc_ecma_transforms_optimization/src/simplify/branch/mod.rs
View File

@ -82,6 +82,12 @@ impl VisitMut for Remover {
e.visit_mut_children_with(self);
match e {
Expr::Seq(s) => {
if s.exprs.is_empty() {
*e = Expr::dummy();
}
}
Expr::Assign(AssignExpr {
op: op!("="),
left: PatOrExpr::Pat(l),
@ -154,6 +160,19 @@ impl VisitMut for Remover {
*e = *cond.cons.take();
}
Expr::Bin(be) => match (be.left.is_invalid(), be.right.is_invalid()) {
(true, true) => {
*e = Expr::dummy();
}
(true, false) => {
*e = *be.right.take();
}
(false, true) => {
*e = *be.left.take();
}
_ => {}
},
_ => {}
}
}
@ -189,7 +208,7 @@ impl VisitMut for Remover {
if cfg!(feature = "debug") {
debug!("Removing dead branches");
}
self.fold_stmt_like(n)
self.fold_stmt_like(n);
}
fn visit_mut_object_pat(&mut self, p: &mut ObjectPat) {
@ -1483,6 +1502,10 @@ fn ignore_result(e: Expr) -> Option<Expr> {
exprs.extend(last);
if exprs.is_empty() {
return None;
}
Some(Expr::Seq(SeqExpr { span, exprs }))
}

18
crates/swc_ecma_transforms_optimization/tests/simplify.rs
View File

@ -631,6 +631,24 @@ test!(
"
);
test!(
Syntax::default(),
|_| dead_branch_remover(),
issue_4272,
"
function oe() {
var e, t;
return t !== i && (e, t = t), e = t;
}
",
"
function oe() {
var e, t;
return e = t;
}
"
);
test!(
Syntax::default(),
|_| chain!(