diff --git a/exptostd.go b/exptostd.go
index c629d99..6dc61cb 100644
--- a/exptostd.go
+++ b/exptostd.go
@@ -311,7 +311,18 @@ func getGoVersion(pass *analysis.Pass) int {
 		return goDevel // true
 	}
 
-	vParts := strings.Split(strings.TrimPrefix(pkgVersion, "go"), ".")
+	raw := strings.TrimPrefix(pkgVersion, "go")
+
+	// prerelease version (go1.24rc1)
+	idx := strings.IndexFunc(raw, func(r rune) bool {
+		return (r < '0' || r > '9') && r != '.'
+	})
+
+	if idx != -1 {
+		raw = raw[:idx]
+	}
+
+	vParts := strings.Split(raw, ".")
 
 	v, err := strconv.Atoi(strings.Join(vParts[:2], ""))
 	if err != nil {