S1008: ignore instructions used in our tests

Author: dominikh

Diff for: simple/s1008/s1008.go

@@ -5,6 +5,7 @@ import (
 	"go/ast"
 	"go/constant"
 	"go/token"
+	"strings"
 
 	"honnef.co/go/tools/analysis/code"
 	"honnef.co/go/tools/analysis/facts/generated"
@@ -88,8 +89,26 @@ func run(pass *analysis.Pass) (any, error) {
 			return
 		}
 
+		hasComments := func(n ast.Node) bool {
+			cmf := cm.Filter(n)
+			for _, groups := range cmf {
+				for _, group := range groups {
+					for _, cmt := range group.List {
+						if strings.HasPrefix(cmt.Text, "//@ diag") {
+							// Staticcheck test cases use comments to mark
+							// expected diagnostics. Ignore these comments so we
+							// can test this check.
+							continue
+						}
+						return true
+					}
+				}
+			}
+			return false
+		}
+
 		// Don't flag if both are commented.
-		if len(cm.Filter(n1)) > 0 && len(cm.Filter(n2)) > 0 {
+		if hasComments(n1) && hasComments(n2) {
 			return
 		}
 

Diff for: simple/s1008/testdata/go1.0/CheckIfReturn/comment.go

@@ -31,13 +31,12 @@ func cmt4(x string) bool {
 	// B
 }
 
-// Hard to test, as the diag line adds a comment.
-//func cmt5(x string) bool {
-//	if len(x) > 0 { // diag(`should use 'return len(x) == 0'`)
-//		return false
-//	}
-//	return true // A
-//}
+func cmt5(x string) bool {
+	if len(x) > 0 { //@ diag(`should use 'return len(x) == 0'`)
+		return false
+	}
+	return true // A
+}
 
 func cmt6(x string) bool {
 	if len(x) > 0 { //@ diag(`should use 'return len(x) == 0'`)