diff --git a/conformance_test/core_language_tests/negative_tests/21_configuration_operations.script b/conformance_test/core_language_tests/negative_tests/21_configuration_operations.script
index 5bc2895a9fe66063ad2e1b6c881025bc5fa2d0e6..3857eb5b124221ad55890d4e0dce8994c153613f 100644
--- a/conformance_test/core_language_tests/negative_tests/21_configuration_operations.script
+++ b/conformance_test/core_language_tests/negative_tests/21_configuration_operations.script
@@ -4035,7 +4035,7 @@ module NegSyn_210307_done_operation_002 {
 <END_MODULE>
 
 <RESULT COUNT 1>
-error: at or before token `->': syntax error, unexpected ->, expecting '{'
+error: at or before token `->': syntax error, unexpected ->, expecting '\{'
 <END_RESULT>
 <RESULT COUNT 1>
 error: at or before token `control': syntax error, unexpected ControlKeyword, expecting \$end
@@ -4091,7 +4091,7 @@ module NegSyn_210307_done_operation_003 {
 <END_MODULE>
 
 <RESULT COUNT 1>
-error: at or before token `->': syntax error, unexpected ->, expecting '{'
+error: at or before token `->': syntax error, unexpected ->, expecting '\{'
 <END_RESULT>
 <RESULT COUNT 1>
 error: at or before token `control': syntax error, unexpected ControlKeyword, expecting \$end
@@ -4640,7 +4640,7 @@ module NegSyn_210308_killed_operation_001 {
 <END_MODULE>
 
 <RESULT COUNT 1>
-error: at or before token `->': syntax error, unexpected ->, expecting '{'
+error: at or before token `->': syntax error, unexpected ->, expecting '\{'
 <END_RESULT>
 <RESULT COUNT 1>
 error: at or before token `control': syntax error, unexpected ControlKeyword, expecting \$end
@@ -4696,7 +4696,7 @@ module NegSyn_210308_killed_operation_002 {
 <END_MODULE>
 
 <RESULT COUNT 1>
-error: at or before token `->': syntax error, unexpected ->, expecting '{'
+error: at or before token `->': syntax error, unexpected ->, expecting '\{'
 <END_RESULT>
 <RESULT COUNT 1>
 error: at or before token `control': syntax error, unexpected ControlKeyword, expecting \$end
@@ -4752,7 +4752,7 @@ module NegSyn_210308_killed_operation_003 {
 <END_MODULE>
 
 <RESULT COUNT 1>
-error: at or before token `->': syntax error, unexpected ->, expecting '{'
+error: at or before token `->': syntax error, unexpected ->, expecting '\{'
 <END_RESULT>
 <RESULT COUNT 1>
 error: at or before token `control': syntax error, unexpected ControlKeyword, expecting \$end