fix corner case in call binding (#2541)

2 files changed, 18 insertions, 22 deletions

diff --git a/lib/compress.js b/lib/compress.js
index dc761948..6bdd1599 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -701,7 +701,7 @@ merge(Compressor.prototype, {
     function make_sequence(orig, expressions) {
         if (expressions.length == 1) return expressions[0];
         return make_node(AST_Sequence, orig, {
-            expressions: expressions
+            expressions: expressions.reduce(merge_sequence, [])
         });
     }
 
@@ -758,6 +758,7 @@ merge(Compressor.prototype, {
         } else {
             array.push(node);
         }
+        return array;
     }
 
     function as_statement_array(thing) {
@@ -1397,13 +1398,7 @@ merge(Compressor.prototype, {
             function cons_seq(right) {
                 n--;
                 var left = prev.body;
-                if (!(left instanceof AST_Sequence)) {
-                    left = make_node(AST_Sequence, left, {
-                        expressions: [ left ]
-                    });
-                }
-                merge_sequence(left.expressions, right);
-                return left.transform(compressor);
+                return make_sequence(left, [ left, right ]).transform(compressor);
             };
             var n = 0, prev;
             for (var i = 0, len = statements.length; i < len; i++) {
@@ -2501,7 +2496,7 @@ merge(Compressor.prototype, {
                                 if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) {
                                     compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
                                     if (def.value) {
-                                        merge_sequence(side_effects, make_node(AST_Assign, def, {
+                                        side_effects.push(make_node(AST_Assign, def, {
                                             operator: "=",
                                             left: make_node(AST_SymbolRef, def.name, def.name),
                                             right: def.value
@@ -2515,7 +2510,7 @@ merge(Compressor.prototype, {
                             if (def.value) {
                                 if (side_effects.length > 0) {
                                     if (tail.length > 0) {
-                                        merge_sequence(side_effects, def.value);
+                                        side_effects.push(def.value);
                                         def.value = make_sequence(def.value, side_effects);
                                     } else {
                                         body.push(make_node(AST_SimpleStatement, node, {
@@ -2530,14 +2525,14 @@ merge(Compressor.prototype, {
                             }
                         } else if (sym.orig[0] instanceof AST_SymbolCatch) {
                             var value = def.value && def.value.drop_side_effect_free(compressor);
-                            if (value) merge_sequence(side_effects, value);
+                            if (value) side_effects.push(value);
                             def.value = null;
                             head.push(def);
                         } else {
                             var value = def.value && def.value.drop_side_effect_free(compressor);
                             if (value) {
                                 compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
-                                merge_sequence(side_effects, value);
+                                side_effects.push(value);
                             } else {
                                 compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
                             }
@@ -2868,7 +2863,7 @@ merge(Compressor.prototype, {
                 var node = nodes[i].drop_side_effect_free(compressor, first_in_statement);
                 changed |= node !== nodes[i];
                 if (node) {
-                    merge_sequence(ret, node);
+                    ret.push(node);
                     first_in_statement = false;
                 }
             }
@@ -2983,7 +2978,7 @@ merge(Compressor.prototype, {
             var expr = last.drop_side_effect_free(compressor);
             if (expr === last) return this;
             var expressions = this.expressions.slice(0, -1);
-            if (expr) merge_sequence(expressions, expr);
+            if (expr) expressions.push(expr);
             return make_sequence(this, expressions);
         });
     })(function(node, func){
@@ -3692,7 +3687,7 @@ merge(Compressor.prototype, {
         trim_right_for_undefined();
         if (end > 0 && compressor.option("cascade")) trim_left_for_assignment();
         if (end == 0) {
-            self = maintain_this_binding(compressor.parent(), self, expressions[0]);
+            self = maintain_this_binding(compressor.parent(), compressor.self(), expressions[0]);
             if (!(self instanceof AST_Sequence)) self = self.optimize(compressor);
             return self;
         }
@@ -4044,10 +4039,10 @@ merge(Compressor.prototype, {
                 var ll = self.left.evaluate(compressor);
                 if (!ll) {
                     compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start);
-                    return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
+                    return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor);
                 } else if (ll !== self.left) {
                     compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
-                    return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
+                    return maintain_this_binding(compressor.parent(), compressor.self(), self.right).optimize(compressor);
                 }
                 if (compressor.option("booleans") && compressor.in_boolean_context()) {
                     var rr = self.right.evaluate(compressor);
@@ -4067,10 +4062,10 @@ merge(Compressor.prototype, {
                 var ll = self.left.evaluate(compressor);
                 if (!ll) {
                     compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start);
-                    return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
+                    return maintain_this_binding(compressor.parent(), compressor.self(), self.right).optimize(compressor);
                 } else if (ll !== self.left) {
                     compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start);
-                    return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
+                    return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor);
                 }
                 if (compressor.option("booleans") && compressor.in_boolean_context()) {
                     var rr = self.right.evaluate(compressor);
@@ -4509,10 +4504,10 @@ merge(Compressor.prototype, {
         if (cond !== self.condition) {
             if (cond) {
                 compressor.warn("Condition always true [{file}:{line},{col}]", self.start);
-                return maintain_this_binding(compressor.parent(), self, self.consequent);
+                return maintain_this_binding(compressor.parent(), compressor.self(), self.consequent);
             } else {
                 compressor.warn("Condition always false [{file}:{line},{col}]", self.start);
-                return maintain_this_binding(compressor.parent(), self, self.alternative);
+                return maintain_this_binding(compressor.parent(), compressor.self(), self.alternative);
             }
         }
         var negated = cond.negate(compressor, first_in_statement(compressor));
diff --git a/test/compress/issue-973.js b/test/compress/issue-973.js
index fee05dfc..a9fcd84f 100644
--- a/test/compress/issue-973.js
+++ b/test/compress/issue-973.js
@@ -1,7 +1,8 @@
 this_binding_conditionals: {
     options = {
         conditionals: true,
-        evaluate    : true
+        evaluate: true,
+        side_effects: true,
     };
     input: {
         (1 && a)();