From 22a09ea7c599e2618ee933ed56ca165a3d2d663b Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 29 Oct 2019 17:06:57 +0800
Subject: fix corner case in `unsafe_math` (#3548)

fixes #3547
---
 lib/compress.js | 37 ++++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

(limited to 'lib')

diff --git a/lib/compress.js b/lib/compress.js
index 3058b678..d37108d1 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -6024,9 +6024,12 @@ merge(Compressor.prototype, {
                 if (self.right instanceof AST_Constant
                     && self.left instanceof AST_Binary
                     && self.left.operator != "%"
-                    && PRECEDENCE[self.left.operator] == PRECEDENCE[self.operator]) {
+                    && PRECEDENCE[self.left.operator] == PRECEDENCE[self.operator]
+                    && self.left.is_number(compressor)) {
                     if (self.left.left instanceof AST_Constant
-                        && (self.left.operator != "+" || self.left.right.is_number(compressor))) {
+                        && (self.operator != "+"
+                            || self.left.left.is_boolean(compressor)
+                            || self.left.left.is_number(compressor))) {
                         self = make_node(AST_Binary, self, {
                             operator: self.left.operator,
                             left: make_node(AST_Binary, self.left, {
@@ -6038,19 +6041,23 @@ merge(Compressor.prototype, {
                             }),
                             right: self.left.right
                         });
-                    } else if (self.left.right instanceof AST_Constant
-                        && (self.left.operator != "+" || self.left.left.is_number(compressor))) {
-                        self = make_node(AST_Binary, self, {
-                            operator: self.left.operator,
-                            left: self.left.left,
-                            right: make_node(AST_Binary, self.left, {
-                                operator: align(self.left.operator, self.operator),
-                                left: self.left.right,
-                                right: self.right,
-                                start: self.left.right.start,
-                                end: self.right.end
-                            })
-                        });
+                    } else if (self.left.right instanceof AST_Constant) {
+                        var op = align(self.left.operator, self.operator);
+                        if (op != "+"
+                            || self.left.right.is_boolean(compressor)
+                            || self.left.right.is_number(compressor)) {
+                            self = make_node(AST_Binary, self, {
+                                operator: self.left.operator,
+                                left: self.left.left,
+                                right: make_node(AST_Binary, self.left, {
+                                    operator: op,
+                                    left: self.left.right,
+                                    right: self.right,
+                                    start: self.left.right.start,
+                                    end: self.right.end
+                                })
+                            });
+                        }
                     }
                 }
                 break;
-- 
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