diff --git a/src/asm/symbol.c b/src/asm/symbol.c
index 1c70b04e..2d6005b1 100644
--- a/src/asm/symbol.c
+++ b/src/asm/symbol.c
@@ -96,6 +96,7 @@ static char const *Callback__FILE__(void)
 	char const *fileName = fstk_GetFileName();
 	size_t j = 1;
 
+	assert(fileName[0]);
 	/* The assertion above ensures the loop runs at least once */
 	for (size_t i = 0; fileName[i]; i++, j++) {
 		/* Account for the extra backslash inserted below */