diff --git a/go/tools/builders/nogo_main.go b/go/tools/builders/nogo_main.go
index 2830a666..ce0e6e39 100644
--- a/go/tools/builders/nogo_main.go
+++ b/go/tools/builders/nogo_main.go
@@ -386,13 +386,11 @@ func checkAnalysisResults(actions []*action, pkg *goPackage) string {
 		}
 		// Discard diagnostics based on the analyzer configuration.
 		for _, d := range act.diagnostics {
-			// NOTE(golang.org/issue/31008): nilness does not set positions,
-			// so don't assume the position is valid.
-			f := pkg.fset.File(d.Pos)
-			filename := "-"
-			if f != nil {
-				filename = f.Name()
+			file := pkg.fset.File(d.Pos)
+			if file == nil {
+				continue
 			}
+			filename := file.Name()
 			include := true
 			if len(config.onlyFiles) > 0 {
 				// This analyzer emits diagnostics for only a set of files.