fix delete on sequence

Author: alexlamsl

lib/compress.js

@@ -3032,7 +3032,11 @@ merge(Compressor.prototype, {
         if (!compressor.option("side_effects"))
             return self;
         self.car = self.car.drop_side_effect_free(compressor, first_in_statement(compressor));
-        if (!self.car) return maintain_this_binding(compressor.parent(), self, self.cdr);
+        if (!self.car) {
+            if (self.cdr instanceof AST_NaN || self.cdr instanceof AST_Infinity)
+                return self.cdr.clone().optimize(compressor);
+            return maintain_this_binding(compressor.parent(), self, self.cdr);
+        }
         if (compressor.option("cascade")) {
             var left;
             if (self.car instanceof AST_Assign
@@ -3607,6 +3611,14 @@ merge(Compressor.prototype, {
         return self;
     });
 
+    function in_delete(parent) {
+        return parent instanceof AST_UnaryPrefix && parent.operator == "delete";
+    }
+
+    function is_atomic(parent, self) {
+        return parent.expression instanceof AST_SymbolRef || parent.expression.TYPE === self.TYPE;
+    }
+
     OPT(AST_Undefined, function(self, compressor){
         if (compressor.option("unsafe")) {
             var undef = find_variable(compressor, "undefined");
@@ -3621,10 +3633,7 @@ merge(Compressor.prototype, {
             }
         }
         var parent = compressor.parent();
-        if (parent instanceof AST_UnaryPrefix
-            && parent.operator == "delete"
-            && (parent.expression instanceof AST_SymbolRef
-                || parent.expression.TYPE === self.TYPE)) return self;
+        if (in_delete(parent) && is_atomic(parent, self)) return self;
         return make_node(AST_UnaryPrefix, self, {
             operator: "void",
             expression: make_node(AST_Number, self, {
@@ -3635,12 +3644,10 @@ merge(Compressor.prototype, {
 
     OPT(AST_Infinity, function(self, compressor){
         var parent = compressor.parent();
-        if (parent instanceof AST_UnaryPrefix
-            && parent.operator == "delete"
-            && (parent.expression instanceof AST_SymbolRef
-                || parent.expression.TYPE === self.TYPE))
-            return self;
+        var del = in_delete(parent);
+        if (del && is_atomic(parent, self)) return self;
         if (compressor.option("keep_infinity")
+            && !(del && !is_atomic(parent, self))
             && !find_variable(compressor, "Infinity"))
             return self;
         return make_node(AST_Binary, self, {
@@ -3656,10 +3663,7 @@ merge(Compressor.prototype, {
 
     OPT(AST_NaN, function(self, compressor){
         var parent = compressor.parent();
-        if (parent instanceof AST_UnaryPrefix
-                && parent.operator == "delete"
-                && !(parent.expression instanceof AST_SymbolRef
-                    || parent.expression.TYPE === self.TYPE)
+        if (in_delete(parent) && !is_atomic(parent, self)
             || find_variable(compressor, "NaN")) {
             return make_node(AST_Binary, self, {
                 operator: "/",

test/compress/sequences.js

@@ -466,3 +466,73 @@ issue_1758: {
     }
     expect_stdout: "undefined"
 }
+
+delete_seq_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        console.log(delete (1, undefined));
+        console.log(delete (1, void 0));
+        console.log(delete (1, Infinity));
+        console.log(delete (1, 1 / 0));
+        console.log(delete (1, NaN));
+        console.log(delete (1, 0 / 0));
+    }
+    expect: {
+        console.log(delete void 0);
+        console.log(delete void 0);
+        console.log(delete (1 / 0));
+        console.log(delete (1 / 0));
+        console.log(delete (0 / 0));
+        console.log(delete (0 / 0));
+    }
+    expect_stdout: true
+}
+
+delete_seq_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        console.log(delete (1, 2, undefined));
+        console.log(delete (1, 2, void 0));
+        console.log(delete (1, 2, Infinity));
+        console.log(delete (1, 2, 1 / 0));
+        console.log(delete (1, 2, NaN));
+        console.log(delete (1, 2, 0 / 0));
+    }
+    expect: {
+        console.log(delete void 0);
+        console.log(delete void 0);
+        console.log(delete (1 / 0));
+        console.log(delete (1 / 0));
+        console.log(delete (0 / 0));
+        console.log(delete (0 / 0));
+    }
+    expect_stdout: true
+}
+
+delete_seq_3: {
+    options = {
+        keep_infinity: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(delete (1, 2, undefined));
+        console.log(delete (1, 2, void 0));
+        console.log(delete (1, 2, Infinity));
+        console.log(delete (1, 2, 1 / 0));
+        console.log(delete (1, 2, NaN));
+        console.log(delete (1, 2, 0 / 0));
+    }
+    expect: {
+        console.log(delete void 0);
+        console.log(delete void 0);
+        console.log(delete (1 / 0));
+        console.log(delete (1 / 0));
+        console.log(delete (0 / 0));
+        console.log(delete (0 / 0));
+    }
+    expect_stdout: true
+}