Permit omission of a colon before a message-typed map value.
diff --git a/proto/text_parser.go b/proto/text_parser.go
index ddd9579..d1caeff 100644
--- a/proto/text_parser.go
+++ b/proto/text_parser.go
@@ -570,7 +570,7 @@
 				if err := p.consumeToken("value"); err != nil {
 					return err
 				}
-				if err := p.consumeToken(":"); err != nil {
+				if err := p.checkForColon(props.mvalprop, dst.Type().Elem()); err != nil {
 					return err
 				}
 				if err := p.readAny(val, props.mvalprop); err != nil {