diff --git a/ChangeLog b/ChangeLog
index 4bf555b26a..dbd13656be 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Apr 18 12:48:51 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (parser_yylex): seems like a symbol-literal when spaces
+	  are unbalanced.  [ruby-core:29578]
+
 Sun Apr 18 12:32:03 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (string_content): preserve cond_stack and cmdarg_stack.
diff --git a/bootstraptest/test_syntax.rb b/bootstraptest/test_syntax.rb
index 44db11babf..30219c048e 100644
--- a/bootstraptest/test_syntax.rb
+++ b/bootstraptest/test_syntax.rb
@@ -890,3 +890,6 @@ assert_valid_syntax('x y { "#{}".z { } }', bug1240)
 assert_valid_syntax('x y { "#{}".z do end }', bug1240)
 
 assert_valid_syntax('y "#{a 1}" do end', '[ruby-core:29579]')
+
+bug3163 = '[ruby-core:29578]'
+assert_valid_syntax('foo = 1; foo :bar', bug3163)
diff --git a/parse.y b/parse.y
index fd788daacd..6a33f08e35 100644
--- a/parse.y
+++ b/parse.y
@@ -7192,7 +7192,8 @@ parser_yylex(struct parser_params *parser)
 	    lex_state = EXPR_DOT;
 	    return tCOLON2;
 	}
-	if (lex_state == EXPR_END || lex_state == EXPR_ENDARG || (c != -1 && ISSPACE(c))) {
+	if ((!space_seen && (lex_state == EXPR_END || lex_state == EXPR_ENDARG)) ||
+	    (c != -1 && ISSPACE(c))) {
 	    pushback(c);
 	    lex_state = EXPR_BEG;
 	    return ':';