Fix unmarshal null to existing value

gen/decoder.go

@@ -320,7 +320,6 @@ func (g *Generator) genTypeDecoderNoCheck(t reflect.Type, out string, tags field
 		return fmt.Errorf("don't know how to decode %v", t)
 	}
 	return nil
-
 }
 
 func (g *Generator) interfaceIsEasyjsonUnmarshaller(t reflect.Type) bool {
@@ -514,11 +513,6 @@ func (g *Generator) genStructDecoder(t reflect.Type) error {
 	fmt.Fprintln(g.out, "  for !in.IsDelim('}') {")
 	fmt.Fprintf(g.out, "    key := in.UnsafeFieldName(%v)\n", g.skipMemberNameUnescaping)
 	fmt.Fprintln(g.out, "    in.WantColon()")
-	fmt.Fprintln(g.out, "    if in.IsNull() {")
-	fmt.Fprintln(g.out, "       in.Skip()")
-	fmt.Fprintln(g.out, "       in.WantComma()")
-	fmt.Fprintln(g.out, "       continue")
-	fmt.Fprintln(g.out, "    }")
 
 	fmt.Fprintln(g.out, "    switch key {")
 	for _, f := range fs {

tests/basic_test.go

@@ -205,7 +205,6 @@ func TestEncodingFlags(t *testing.T) {
 			t.Errorf("[%v] easyjson.Marshal(%+v) = %v; want %v", i, test.In, v, test.Want)
 		}
 	}
-
 }
 
 func TestNestedEasyJsonMarshal(t *testing.T) {
@@ -329,3 +328,17 @@ func TestNil(t *testing.T) {
 		t.Errorf("Wanted null, got %q", s)
 	}
 }
+
+func TestUnmarshalNull(t *testing.T) {
+	p := primitiveTypesValue
+
+	data := `{"Ptr":null}`
+
+	if err := easyjson.Unmarshal([]byte(data), &p); err != nil {
+		t.Errorf("easyjson.Unmarshal() error: %v", err)
+	}
+
+	if p.Ptr != nil {
+		t.Errorf("Wanted nil, got %q", *p.Ptr)
+	}
+}