cmd/cgo: use slices.ContainsFunc

Now that Go 1.22.6 is the minimum bootstrap toolchain (cf. CL 606156),
the slices package (introduced in Go 1.21) can be used in packages built
using the bootstrap toolchain.

For #64751

Change-Id: Ib36f39016f57c5e110f78a85ca9c806d91356024
Reviewed-on: https://go-review.googlesource.com/c/go/+/612316
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/cgo/gcc.go

@@ -24,6 +24,7 @@ import (
 	"math"
 	"os"
 	"os/exec"
+	"slices"
 	"strconv"
 	"strings"
 	"unicode"
@@ -781,16 +782,13 @@ func (p *Package) mangleName(n *Name) {
 }
 
 func (f *File) isMangledName(s string) bool {
-	prefix := "_C"
-	if strings.HasPrefix(s, prefix) {
-		t := s[len(prefix):]
-		for _, k := range nameKinds {
-			if strings.HasPrefix(t, k+"_") {
-				return true
-			}
-		}
+	t, ok := strings.CutPrefix(s, "_C")
+	if !ok {
+		return false
 	}
-	return false
+	return slices.ContainsFunc(nameKinds, func(k string) bool {
+		return strings.HasPrefix(t, k+"_")
+	})
 }
 
 // rewriteCalls rewrites all calls that pass pointers to check that
@@ -1050,12 +1048,9 @@ func (p *Package) hasPointer(f *File, t ast.Expr, top bool) bool {
 		}
 		return p.hasPointer(f, t.Elt, top)
 	case *ast.StructType:
-		for _, field := range t.Fields.List {
-			if p.hasPointer(f, field.Type, top) {
-				return true
-			}
-		}
-		return false
+		return slices.ContainsFunc(t.Fields.List, func(field *ast.Field) bool {
+			return p.hasPointer(f, field.Type, top)
+		})
 	case *ast.StarExpr: // Pointer type.
 		if !top {
 			return true
@@ -3202,12 +3197,9 @@ func (c *typeConv) dwarfHasPointer(dt dwarf.Type, pos token.Pos) bool {
 		return c.dwarfHasPointer(dt.Type, pos)
 
 	case *dwarf.StructType:
-		for _, f := range dt.Field {
-			if c.dwarfHasPointer(f.Type, pos) {
-				return true
-			}
-		}
-		return false
+		return slices.ContainsFunc(dt.Field, func(f *dwarf.StructField) bool {
+			return c.dwarfHasPointer(f.Type, pos)
+		})
 
 	case *dwarf.TypedefType:
 		if dt.Name == "_GoString_" || dt.Name == "_GoBytes_" {