diff --git a/compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/InternalCompilerArgument.kt b/compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/InternalCompilerArgument.kt
index d896cc7df18..86dc1c9a3dc 100644
--- a/compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/InternalCompilerArgument.kt
+++ b/compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/InternalCompilerArgument.kt
@@ -59,7 +59,7 @@ class LanguageSettingsParser : AbstractInternalArgumentParser<ManualLanguageFeat
             return null
         }
 
-        tail.getOrNull(0) ?: return reportAndReturnNull("Incorrect internal argument syntax, missing colon: $wholeArgument")
+        if (tail.getOrNull(0) != ':') return reportAndReturnNull("Incorrect internal argument syntax, missing colon: $wholeArgument")
 
         val modificator = tail.getOrNull(1)
         val languageFeatureState = when (modificator) {