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fix corner cases with logical assignment operators (#4816)

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fixes #4815
This commit is contained in:
Alex Lam S.L
2021-03-23 05:02:45 +00:00
committed by GitHub
parent 44394e61c9
commit e7be38b42a
2 changed files with 74 additions and 15 deletions
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49
lib/compress.js
View File

@@ -814,26 +814,39 @@ merge(Compressor.prototype, {
def(AST_Assign, function(tw, descend, compressor) {
var node = this;
var left = node.left;
if (node.operator == "=" && left.equivalent_to(node.right) && !left.has_side_effects(compressor)) {
node.right.walk(tw);
walk_prop(left);
node.__drop = true;
} else if (!(left instanceof AST_Destructured || left instanceof AST_SymbolRef)) {
var scan = left instanceof AST_Destructured || left instanceof AST_SymbolRef;
switch (node.operator) {
case "=":
if (left.equivalent_to(node.right) && !left.has_side_effects(compressor)) {
node.right.walk(tw);
walk_prop(left);
node.__drop = true;
return true;
}
if (scan) {
walk_assign();
return true;
}
mark_assignment_to_arguments(left);
return;
} else switch (node.operator) {
case "=":
walk_assign();
break;
case "&&=":
case "||=":
case "??=":
left.walk(tw);
push(tw);
walk_assign();
if (scan) {
walk_assign();
} else {
mark_assignment_to_arguments(left);
node.right.walk(tw);
}
pop(tw);
break;
return true;
default:
if (!scan) {
mark_assignment_to_arguments(left);
return;
}
var d = left.definition();
d.assignments++;
var fixed = d.fixed;
@@ -860,8 +873,8 @@ merge(Compressor.prototype, {
left.walk(tw);
d.fixed = false;
}
return true;
}
return true;
function walk_prop(lhs) {
if (lhs instanceof AST_Dot) {
@@ -7229,9 +7242,15 @@ merge(Compressor.prototype, {
}
if (left.has_side_effects(compressor)) return this;
var right = this.right;
this.write_only = !(lazy_op[this.operator.slice(0, -1)] && right.has_side_effects(compressor));
if (!root_expr(left).is_constant_expression(compressor.find_parent(AST_Scope))) return this;
return right.drop_side_effect_free(compressor);
if (lazy_op[this.operator.slice(0, -1)]) {
this.write_only = !right.has_side_effects(compressor);
} else {
this.write_only = true;
if (root_expr(left).is_constant_expression(compressor.find_parent(AST_Scope))) {
return right.drop_side_effect_free(compressor);
}
}
return this;
});
def(AST_Await, function(compressor) {
if (!compressor.option("awaits")) return this;

40
test/compress/assignments.js
View File

@@ -549,3 +549,43 @@ logical_side_effects: {
expect_stdout: "PASS"
node_version: ">=15"
}
issue_4815_1: {
options = {
evaluate: true,
reduce_vars: true,
toplevel: true,
unused: true,
}
input: {
var a = "PASS";
42..p &&= a = "FAIL";
console.log(a);
}
expect: {
var a = "PASS";
42..p &&= a = "FAIL";
console.log(a);
}
expect_stdout: "PASS"
node_version: ">=15"
}
issue_4815_2: {
options = {
pure_getters: "strict",
side_effects: true,
}
input: {
var a = "PASS";
42..p &&= a = "FAIL";
console.log(a);
}
expect: {
var a = "PASS";
42..p &&= a = "FAIL";
console.log(a);
}
expect_stdout: "PASS"
node_version: ">=15"
}