types2, go/types: use slices.SortFunc

Now that we're bootstrapping from a toolchain that has the slices
package.

Updates #64751

Change-Id: I3227e55f87e033dae63a2d1712b7f9373fe49731
Reviewed-on: https://go-review.googlesource.com/c/go/+/610603
Reviewed-by: Robert Griesemer <[email protected]>
Auto-Submit: Cuong Manh Le <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Findley <[email protected]>

Author: cuonglm

src/cmd/compile/internal/types2/initorder.go

@@ -5,10 +5,11 @@
 package types2
 
 import (
+	"cmp"
 	"container/heap"
 	"fmt"
 	. "internal/types/errors"
-	"sort"
+	"slices"
 )
 
 // initOrder computes the Info.InitOrder for package variables.
@@ -257,8 +258,8 @@ func dependencyGraph(objMap map[Object]*declInfo) []*graphNode {
 	// throughout the function graph, the cost of removing a function at
 	// position X is proportional to cost * (len(funcG)-X). Therefore, we should
 	// remove high-cost functions last.
-	sort.Slice(funcG, func(i, j int) bool {
-		return funcG[i].cost() < funcG[j].cost()
+	slices.SortFunc(funcG, func(a, b *graphNode) int {
+		return cmp.Compare(a.cost(), b.cost())
 	})
 	for _, n := range funcG {
 		// connect each predecessor p of n with each successor s

src/cmd/compile/internal/types2/stmt.go

@@ -11,7 +11,7 @@ import (
 	"go/constant"
 	"internal/buildcfg"
 	. "internal/types/errors"
-	"sort"
+	"slices"
 )
 
 func (check *Checker) funcBody(decl *declInfo, name string, sig *Signature, body *syntax.BlockStmt, iota constant.Value) {
@@ -60,8 +60,8 @@ func (check *Checker) usage(scope *Scope) {
 			unused = append(unused, v)
 		}
 	}
-	sort.Slice(unused, func(i, j int) bool {
-		return cmpPos(unused[i].pos, unused[j].pos) < 0
+	slices.SortFunc(unused, func(a, b *Var) int {
+		return cmpPos(a.pos, b.pos)
 	})
 	for _, v := range unused {
 		check.softErrorf(v.pos, UnusedVar, "declared and not used: %s", v.name)

src/go/types/initorder.go

@@ -12,7 +12,7 @@ import (
 	"go/token"
 	"internal/buildcfg"
 	. "internal/types/errors"
-	"sort"
+	"slices"
 )
 
 func (check *Checker) funcBody(decl *declInfo, name string, sig *Signature, body *ast.BlockStmt, iota constant.Value) {
@@ -61,8 +61,8 @@ func (check *Checker) usage(scope *Scope) {
 			unused = append(unused, v)
 		}
 	}
-	sort.Slice(unused, func(i, j int) bool {
-		return cmpPos(unused[i].pos, unused[j].pos) < 0
+	slices.SortFunc(unused, func(a, b *Var) int {
+		return cmpPos(a.pos, b.pos)
 	})
 	for _, v := range unused {
 		check.softErrorf(v, UnusedVar, "declared and not used: %s", v.name)