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fix corner case in dead_code (#3579)

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fixes #3578
This commit is contained in:
Alex Lam S.L
2019-11-12 05:16:14 +08:00
committed by GitHub
parent 765a06340f
commit 5b20bad4b3
2 changed files with 33 additions and 4 deletions
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10
lib/compress.js
View File

@@ -6545,7 +6545,8 @@ merge(Compressor.prototype, {
} else if (self.left instanceof AST_SymbolRef) { } else if (self.left instanceof AST_SymbolRef) {
if (self.left.is_immutable()) return strip_assignment(); if (self.left.is_immutable()) return strip_assignment();
var def = self.left.definition(); var def = self.left.definition();
var local = def.scope.resolve() === compressor.find_parent(AST_Lambda); var scope = def.scope.resolve();
var local = scope === compressor.find_parent(AST_Lambda);
var level = 0, node, parent = self; var level = 0, node, parent = self;
do { do {
node = parent; node = parent;
@@ -6553,12 +6554,13 @@ merge(Compressor.prototype, {
if (parent instanceof AST_Assign) { if (parent instanceof AST_Assign) {
if (!(parent.left instanceof AST_SymbolRef)) continue; if (!(parent.left instanceof AST_SymbolRef)) continue;
if (parent.left.definition() !== def) continue; if (parent.left.definition() !== def) continue;
if (in_try(level, parent)) break;
def.fixed = false; def.fixed = false;
return strip_assignment(); return strip_assignment();
} else if (parent instanceof AST_Exit) { } else if (parent instanceof AST_Exit) {
if (!local) break; if (!local) break;
if (in_try(level, parent)) break; if (in_try(level, parent)) break;
if (is_reachable(def.scope, [ def ])) break; if (is_reachable(scope, [ def ])) break;
def.fixed = false; def.fixed = false;
return strip_assignment(); return strip_assignment();
} }
@@ -6604,9 +6606,9 @@ merge(Compressor.prototype, {
self.right = make_node(AST_Null, right); self.right = make_node(AST_Null, right);
var may_throw = node.may_throw(compressor); var may_throw = node.may_throw(compressor);
self.right = right; self.right = right;
var scope = self.left.definition().scope.resolve();
var parent; var parent;
while ((parent = compressor.parent(level++)) !== scope) { while (parent = compressor.parent(level++)) {
if (parent === scope) return false;
if (parent instanceof AST_Try) { if (parent instanceof AST_Try) {
if (parent.bfinally) return true; if (parent.bfinally) return true;
if (may_throw && parent.bcatch) return true; if (may_throw && parent.bcatch) return true;

27
test/compress/dead-code.js
View File

@@ -1102,3 +1102,30 @@ catch_return_assign: {
} }
expect_stdout: "PASS" expect_stdout: "PASS"
} }
issue_3578: {
options = {
dead_code: true,
}
input: {
var a = "FAIL", b, c;
try {
b = c.p = b = 0;
} catch (e) {
b += 42;
b && (a = "PASS");
}
console.log(a);
}
expect: {
var a = "FAIL", b, c;
try {
b = c.p = b = 0;
} catch (e) {
b += 42;
b && (a = "PASS");
}
console.log(a);
}
expect_stdout: "PASS"
}