internal: fix unused errors reported by ineffassign

Updates #76704

Author: linsite

internal/goroot/importcfg.go

@@ -38,7 +38,7 @@ func PkgfileMap() (map[string]string, error) {
 			}
 			sp := strings.SplitN(line, " ", 2)
 			if len(sp) != 2 {
-				err = fmt.Errorf("determining pkgfile map: invalid line in go list output: %q", line)
+				stdlibPkgfileErr = fmt.Errorf("determining pkgfile map: invalid line in go list output: %q", line)
 				return
 			}
 			importPath, export := sp[0], sp[1]

internal/imports/sourcex_test.go

@@ -78,6 +78,9 @@ func TestSource(t *testing.T) {
 	opts := imports.Options{}
 	// ApplyFixes needs a non-nil opts
 	got, err := imports.ApplyFixes(fixes, "tfile.go", []byte(fx), &opts, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	fxwant := "package main\n\nimport \"bar.com/foo\"\n\nvar _ = foo.Foo\nvar _ = foo.Bar\n"
 	if diff := cmp.Diff(string(got), fxwant); diff != "" {