diff --git a/compiler/linter.nim b/compiler/linter.nim
index 77e0a84e4d..1ae1fb0973 100644
--- a/compiler/linter.nim
+++ b/compiler/linter.nim
@@ -55,7 +55,9 @@ proc beautifyName(s: string, k: TSymKind): string =
   inc i
   while i < s.len:
     if s[i] == '_':
-      if i > 0 and s[i-1] in {'A'..'Z'}:
+      if i+1 >= s.len:
+        discard "trailing underscores should be stripped off"
+      elif i > 0 and s[i-1] in {'A'..'Z'}:
         # don't skip '_' as it's essential for e.g. 'GC_disable'
         result.add('_')
         inc i