preserve constant modification under strict mode (#2717)

2018-01-04 15:53:53 +08:00
parent 9b58b54e2d
commit 7a6d452b54
2 changed files with 57 additions and 1 deletions
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3279,7 +3279,12 @@ merge(Compressor.prototype, {
        });
        def(AST_Assign, function(compressor){
            var left = this.left;
-            if (left.has_side_effects(compressor)) return this;
+            if (left.has_side_effects(compressor)
+                || compressor.has_directive("use strict")
+                    && left instanceof AST_PropAccess
+                    && left.expression.is_constant()) {
+                return this;
+            }
            this.write_only = true;
            while (left instanceof AST_PropAccess) {
                left = left.expression;