libgo: update to Go1.17rc2

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/341629

7 files changed, 816 insertions, 181 deletions

diff --git a/libgo/go/reflect/all_test.go b/libgo/go/reflect/all_test.go
index c73ef47..7fa815f 100644
--- a/libgo/go/reflect/all_test.go
+++ b/libgo/go/reflect/all_test.go
@@ -15,6 +15,8 @@ import (
 	"math/rand"
 	"os"
 	. "reflect"
+	"reflect/internal/example1"
+	"reflect/internal/example2"
 	"runtime"
 	"sort"
 	"strconv"
@@ -1945,6 +1947,22 @@ func BenchmarkCall(b *testing.B) {
 	})
 }
 
+type myint int64
+
+func (i *myint) inc() {
+	*i = *i + 1
+}
+
+func BenchmarkCallMethod(b *testing.B) {
+	b.ReportAllocs()
+	z := new(myint)
+
+	v := ValueOf(z.inc)
+	for i := 0; i < b.N; i++ {
+		v.Call(nil)
+	}
+}
+
 func BenchmarkCallArgCopy(b *testing.B) {
 	byteArray := func(n int) Value {
 		return Zero(ArrayOf(n, TypeOf(byte(0))))
@@ -2903,6 +2921,7 @@ func TestFieldPkgPath(t *testing.T) {
 		index    []int
 		pkgPath  string
 		embedded bool
+		exported bool
 	}
 
 	checkPkgPath := func(name string, s []pkgpathTest) {
@@ -2914,27 +2933,63 @@ func TestFieldPkgPath(t *testing.T) {
 			if got, want := f.Anonymous, test.embedded; got != want {
 				t.Errorf("%s: Field(%d).Anonymous = %v, want %v", name, test.index, got, want)
 			}
+			if got, want := f.IsExported(), test.exported; got != want {
+				t.Errorf("%s: Field(%d).IsExported = %v, want %v", name, test.index, got, want)
+			}
 		}
 	}
 
 	checkPkgPath("testStruct", []pkgpathTest{
-		{[]int{0}, "", false},             // Exported
-		{[]int{1}, "reflect_test", false}, // unexported
-		{[]int{2}, "", true},              // OtherPkgFields
-		{[]int{2, 0}, "", false},          // OtherExported
-		{[]int{2, 1}, "reflect", false},   // otherUnexported
-		{[]int{3}, "reflect_test", true},  // int
-		{[]int{4}, "reflect_test", true},  // *x
+		{[]int{0}, "", false, true},              // Exported
+		{[]int{1}, "reflect_test", false, false}, // unexported
+		{[]int{2}, "", true, true},               // OtherPkgFields
+		{[]int{2, 0}, "", false, true},           // OtherExported
+		{[]int{2, 1}, "reflect", false, false},   // otherUnexported
+		{[]int{3}, "reflect_test", true, false},  // int
+		{[]int{4}, "reflect_test", true, false},  // *x
 	})
 
 	type localOtherPkgFields OtherPkgFields
 	typ = TypeOf(localOtherPkgFields{})
 	checkPkgPath("localOtherPkgFields", []pkgpathTest{
-		{[]int{0}, "", false},        // OtherExported
-		{[]int{1}, "reflect", false}, // otherUnexported
+		{[]int{0}, "", false, true},         // OtherExported
+		{[]int{1}, "reflect", false, false}, // otherUnexported
 	})
 }
 
+func TestMethodPkgPath(t *testing.T) {
+	type I interface {
+		x()
+		X()
+	}
+	typ := TypeOf((*interface {
+		I
+		y()
+		Y()
+	})(nil)).Elem()
+
+	tests := []struct {
+		name     string
+		pkgPath  string
+		exported bool
+	}{
+		{"X", "", true},
+		{"Y", "", true},
+		{"x", "reflect_test", false},
+		{"y", "reflect_test", false},
+	}
+
+	for _, test := range tests {
+		m, _ := typ.MethodByName(test.name)
+		if got, want := m.PkgPath, test.pkgPath; got != want {
+			t.Errorf("MethodByName(%q).PkgPath = %q, want %q", test.name, got, want)
+		}
+		if got, want := m.IsExported(), test.exported; got != want {
+			t.Errorf("MethodByName(%q).IsExported = %v, want %v", test.name, got, want)
+		}
+	}
+}
+
 func TestVariadicType(t *testing.T) {
 	// Test example from Type documentation.
 	var f func(x int, y ...float64)
@@ -3765,8 +3820,22 @@ type Empty struct{}
 type MyStruct struct {
 	x int `some:"tag"`
 }
+type MyStruct1 struct {
+	x struct {
+		int `some:"bar"`
+	}
+}
+type MyStruct2 struct {
+	x struct {
+		int `some:"foo"`
+	}
+}
 type MyString string
 type MyBytes []byte
+type MyBytesArrayPtr0 *[0]byte
+type MyBytesArrayPtr *[4]byte
+type MyBytesArray0 [0]byte
+type MyBytesArray [4]byte
 type MyRunes []int32
 type MyFunc func()
 type MyByte byte
@@ -4073,6 +4142,30 @@ var convertTests = []struct {
 	{V(MyString("runes♝")), V(MyRunes("runes♝"))},
 	{V(MyRunes("runes♕")), V(MyString("runes♕"))},
 
+	// slice to array pointer
+	{V([]byte(nil)), V((*[0]byte)(nil))},
+	{V([]byte{}), V(new([0]byte))},
+	{V([]byte{7}), V(&[1]byte{7})},
+	{V(MyBytes([]byte(nil))), V((*[0]byte)(nil))},
+	{V(MyBytes([]byte{})), V(new([0]byte))},
+	{V(MyBytes([]byte{9})), V(&[1]byte{9})},
+	{V([]byte(nil)), V(MyBytesArrayPtr0(nil))},
+	{V([]byte{}), V(MyBytesArrayPtr0(new([0]byte)))},
+	{V([]byte{1, 2, 3, 4}), V(MyBytesArrayPtr(&[4]byte{1, 2, 3, 4}))},
+	{V(MyBytes([]byte{})), V(MyBytesArrayPtr0(new([0]byte)))},
+	{V(MyBytes([]byte{5, 6, 7, 8})), V(MyBytesArrayPtr(&[4]byte{5, 6, 7, 8}))},
+
+	{V([]byte(nil)), V((*MyBytesArray0)(nil))},
+	{V([]byte{}), V((*MyBytesArray0)(new([0]byte)))},
+	{V([]byte{1, 2, 3, 4}), V(&MyBytesArray{1, 2, 3, 4})},
+	{V(MyBytes([]byte(nil))), V((*MyBytesArray0)(nil))},
+	{V(MyBytes([]byte{})), V((*MyBytesArray0)(new([0]byte)))},
+	{V(MyBytes([]byte{5, 6, 7, 8})), V(&MyBytesArray{5, 6, 7, 8})},
+	{V(new([0]byte)), V(new(MyBytesArray0))},
+	{V(new(MyBytesArray0)), V(new([0]byte))},
+	{V(MyBytesArrayPtr0(nil)), V((*[0]byte)(nil))},
+	{V((*[0]byte)(nil)), V(MyBytesArrayPtr0(nil))},
+
 	// named types and equal underlying types
 	{V(new(int)), V(new(integer))},
 	{V(new(integer)), V(new(int))},
@@ -4115,6 +4208,9 @@ var convertTests = []struct {
 		x int `some:"bar"`
 	}{}), V(MyStruct{})},
 
+	{V(MyStruct1{}), V(MyStruct2{})},
+	{V(MyStruct2{}), V(MyStruct1{})},
+
 	// can convert *byte and *MyByte
 	{V((*byte)(nil)), V((*MyByte)(nil))},
 	{V((*MyByte)(nil)), V((*byte)(nil))},
@@ -4218,6 +4314,9 @@ func TestConvert(t *testing.T) {
 
 		// vout1 represents the in value converted to the in type.
 		v1 := tt.in
+		if !v1.CanConvert(t1) {
+			t.Errorf("ValueOf(%T(%[1]v)).CanConvert(%s) = false, want true", tt.in.Interface(), t1)
+		}
 		vout1 := v1.Convert(t1)
 		out1 := vout1.Interface()
 		if vout1.Type() != tt.in.Type() || !DeepEqual(out1, tt.in.Interface()) {
@@ -4225,11 +4324,17 @@ func TestConvert(t *testing.T) {
 		}
 
 		// vout2 represents the in value converted to the out type.
+		if !v1.CanConvert(t2) {
+			t.Errorf("ValueOf(%T(%[1]v)).CanConvert(%s) = false, want true", tt.in.Interface(), t2)
+		}
 		vout2 := v1.Convert(t2)
 		out2 := vout2.Interface()
 		if vout2.Type() != tt.out.Type() || !DeepEqual(out2, tt.out.Interface()) {
 			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) = %T(%[3]v), want %T(%[4]v)", tt.in.Interface(), t2, out2, tt.out.Interface())
 		}
+		if got, want := vout2.Kind(), vout2.Type().Kind(); got != want {
+			t.Errorf("ValueOf(%T(%[1]v)).Convert(%s) has internal kind %v want %v", tt.in.Interface(), t1, got, want)
+		}
 
 		// vout3 represents a new value of the out type, set to vout2.  This makes
 		// sure the converted value vout2 is really usable as a regular value.
@@ -4274,6 +4379,22 @@ func TestConvert(t *testing.T) {
 	}
 }
 
+func TestConvertPanic(t *testing.T) {
+	s := make([]byte, 4)
+	p := new([8]byte)
+	v := ValueOf(s)
+	pt := TypeOf(p)
+	if !v.Type().ConvertibleTo(pt) {
+		t.Errorf("[]byte should be convertible to *[8]byte")
+	}
+	if v.CanConvert(pt) {
+		t.Errorf("slice with length 4 should not be convertible to *[8]byte")
+	}
+	shouldPanic("reflect: cannot convert slice with length 4 to pointer to array with length 8", func() {
+		_ = v.Convert(pt)
+	})
+}
+
 var gFloat32 float32
 
 func TestConvertNaNs(t *testing.T) {
@@ -4612,6 +4733,14 @@ func TestArrayOfDirectIface(t *testing.T) {
 	}
 }
 
+// Ensure passing in negative lengths panics.
+// See https://golang.org/issue/43603
+func TestArrayOfPanicOnNegativeLength(t *testing.T) {
+	shouldPanic("reflect: negative length passed to ArrayOf", func() {
+		ArrayOf(-1, TypeOf(byte(0)))
+	})
+}
+
 func TestSliceOf(t *testing.T) {
 	// check construction and use of type not in binary
 	type T int
@@ -6357,148 +6486,142 @@ func clobber() {
 	runtime.GC()
 }
 
-type funcLayoutTest struct {
-	rcvr, t                  Type
-	size, argsize, retOffset uintptr
-	stack                    []byte // pointer bitmap: 1 is pointer, 0 is scalar
-	gc                       []byte
-}
-
-var funcLayoutTests []funcLayoutTest
-
-func init() {
-	var argAlign uintptr = PtrSize
-	roundup := func(x uintptr, a uintptr) uintptr {
-		return (x + a - 1) / a * a
-	}
-
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func(a, b string) string { return "" }).Type(),
-			6 * PtrSize,
-			4 * PtrSize,
-			4 * PtrSize,
-			[]byte{1, 0, 1, 0, 1},
-			[]byte{1, 0, 1, 0, 1},
-		})
+/*
 
+func TestFuncLayout(t *testing.T) {
+	align := func(x uintptr) uintptr {
+		return (x + PtrSize - 1) &^ (PtrSize - 1)
+	}
 	var r []byte
 	if PtrSize == 4 {
 		r = []byte{0, 0, 0, 1}
 	} else {
 		r = []byte{0, 0, 1}
 	}
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func(a, b, c uint32, p *byte, d uint16) {}).Type(),
-			roundup(roundup(3*4, PtrSize)+PtrSize+2, argAlign),
-			roundup(3*4, PtrSize) + PtrSize + 2,
-			roundup(roundup(3*4, PtrSize)+PtrSize+2, argAlign),
-			r,
-			r,
-		})
-
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func(a map[int]int, b uintptr, c interface{}) {}).Type(),
-			4 * PtrSize,
-			4 * PtrSize,
-			4 * PtrSize,
-			[]byte{1, 0, 1, 1},
-			[]byte{1, 0, 1, 1},
-		})
 
 	type S struct {
 		a, b uintptr
 		c, d *byte
 	}
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func(a S) {}).Type(),
-			4 * PtrSize,
-			4 * PtrSize,
-			4 * PtrSize,
-			[]byte{0, 0, 1, 1},
-			[]byte{0, 0, 1, 1},
-		})
-
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			ValueOf((*byte)(nil)).Type(),
-			ValueOf(func(a uintptr, b *int) {}).Type(),
-			roundup(3*PtrSize, argAlign),
-			3 * PtrSize,
-			roundup(3*PtrSize, argAlign),
-			[]byte{1, 0, 1},
-			[]byte{1, 0, 1},
-		})
 
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func(a uintptr) {}).Type(),
-			roundup(PtrSize, argAlign),
-			PtrSize,
-			roundup(PtrSize, argAlign),
-			[]byte{},
-			[]byte{},
-		})
-
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			nil,
-			ValueOf(func() uintptr { return 0 }).Type(),
-			PtrSize,
-			0,
-			0,
-			[]byte{},
-			[]byte{},
-		})
-
-	funcLayoutTests = append(funcLayoutTests,
-		funcLayoutTest{
-			ValueOf(uintptr(0)).Type(),
-			ValueOf(func(a uintptr) {}).Type(),
-			2 * PtrSize,
-			2 * PtrSize,
-			2 * PtrSize,
-			[]byte{1},
-			[]byte{1},
+	type test struct {
+		rcvr, typ                  Type
+		size, argsize, retOffset   uintptr
+		stack, gc, inRegs, outRegs []byte // pointer bitmap: 1 is pointer, 0 is scalar
+		intRegs, floatRegs         int
+		floatRegSize               uintptr
+	}
+	tests := []test{
+		{
+			typ:       ValueOf(func(a, b string) string { return "" }).Type(),
+			size:      6 * PtrSize,
+			argsize:   4 * PtrSize,
+			retOffset: 4 * PtrSize,
+			stack:     []byte{1, 0, 1, 0, 1},
+			gc:        []byte{1, 0, 1, 0, 1},
+		},
+		{
+			typ:       ValueOf(func(a, b, c uint32, p *byte, d uint16) {}).Type(),
+			size:      align(align(3*4) + PtrSize + 2),
+			argsize:   align(3*4) + PtrSize + 2,
+			retOffset: align(align(3*4) + PtrSize + 2),
+			stack:     r,
+			gc:        r,
+		},
+		{
+			typ:       ValueOf(func(a map[int]int, b uintptr, c interface{}) {}).Type(),
+			size:      4 * PtrSize,
+			argsize:   4 * PtrSize,
+			retOffset: 4 * PtrSize,
+			stack:     []byte{1, 0, 1, 1},
+			gc:        []byte{1, 0, 1, 1},
+		},
+		{
+			typ:       ValueOf(func(a S) {}).Type(),
+			size:      4 * PtrSize,
+			argsize:   4 * PtrSize,
+			retOffset: 4 * PtrSize,
+			stack:     []byte{0, 0, 1, 1},
+			gc:        []byte{0, 0, 1, 1},
+		},
+		{
+			rcvr:      ValueOf((*byte)(nil)).Type(),
+			typ:       ValueOf(func(a uintptr, b *int) {}).Type(),
+			size:      3 * PtrSize,
+			argsize:   3 * PtrSize,
+			retOffset: 3 * PtrSize,
+			stack:     []byte{1, 0, 1},
+			gc:        []byte{1, 0, 1},
+		},
+		{
+			typ:       ValueOf(func(a uintptr) {}).Type(),
+			size:      PtrSize,
+			argsize:   PtrSize,
+			retOffset: PtrSize,
+			stack:     []byte{},
+			gc:        []byte{},
+		},
+		{
+			typ:       ValueOf(func() uintptr { return 0 }).Type(),
+			size:      PtrSize,
+			argsize:   0,
+			retOffset: 0,
+			stack:     []byte{},
+			gc:        []byte{},
+		},
+		{
+			rcvr:      ValueOf(uintptr(0)).Type(),
+			typ:       ValueOf(func(a uintptr) {}).Type(),
+			size:      2 * PtrSize,
+			argsize:   2 * PtrSize,
+			retOffset: 2 * PtrSize,
+			stack:     []byte{1},
+			gc:        []byte{1},
 			// Note: this one is tricky, as the receiver is not a pointer. But we
 			// pass the receiver by reference to the autogenerated pointer-receiver
 			// version of the function.
-		})
-}
-
-func TestFuncLayout(t *testing.T) {
-	t.Skip("gccgo does not use funcLayout")
-	for _, lt := range funcLayoutTests {
-		typ, argsize, retOffset, stack, gc, ptrs := FuncLayout(lt.t, lt.rcvr)
-		if typ.Size() != lt.size {
-			t.Errorf("funcLayout(%v, %v).size=%d, want %d", lt.t, lt.rcvr, typ.Size(), lt.size)
-		}
-		if argsize != lt.argsize {
-			t.Errorf("funcLayout(%v, %v).argsize=%d, want %d", lt.t, lt.rcvr, argsize, lt.argsize)
-		}
-		if retOffset != lt.retOffset {
-			t.Errorf("funcLayout(%v, %v).retOffset=%d, want %d", lt.t, lt.rcvr, retOffset, lt.retOffset)
-		}
-		if !bytes.Equal(stack, lt.stack) {
-			t.Errorf("funcLayout(%v, %v).stack=%v, want %v", lt.t, lt.rcvr, stack, lt.stack)
-		}
-		if !bytes.Equal(gc, lt.gc) {
-			t.Errorf("funcLayout(%v, %v).gc=%v, want %v", lt.t, lt.rcvr, gc, lt.gc)
-		}
-		if ptrs && len(stack) == 0 || !ptrs && len(stack) > 0 {
-			t.Errorf("funcLayout(%v, %v) pointers flag=%v, want %v", lt.t, lt.rcvr, ptrs, !ptrs)
+		},
+		// TODO(mknyszek): Add tests for non-zero register count.
+	}
+	for _, lt := range tests {
+		name := lt.typ.String()
+		if lt.rcvr != nil {
+			name = lt.rcvr.String() + "." + name
 		}
+		t.Run(name, func(t *testing.T) {
+			defer SetArgRegs(SetArgRegs(lt.intRegs, lt.floatRegs, lt.floatRegSize))
+
+			typ, argsize, retOffset, stack, gc, inRegs, outRegs, ptrs := FuncLayout(lt.typ, lt.rcvr)
+			if typ.Size() != lt.size {
+				t.Errorf("funcLayout(%v, %v).size=%d, want %d", lt.typ, lt.rcvr, typ.Size(), lt.size)
+			}
+			if argsize != lt.argsize {
+				t.Errorf("funcLayout(%v, %v).argsize=%d, want %d", lt.typ, lt.rcvr, argsize, lt.argsize)
+			}
+			if retOffset != lt.retOffset {
+				t.Errorf("funcLayout(%v, %v).retOffset=%d, want %d", lt.typ, lt.rcvr, retOffset, lt.retOffset)
+			}
+			if !bytes.Equal(stack, lt.stack) {
+				t.Errorf("funcLayout(%v, %v).stack=%v, want %v", lt.typ, lt.rcvr, stack, lt.stack)
+			}
+			if !bytes.Equal(gc, lt.gc) {
+				t.Errorf("funcLayout(%v, %v).gc=%v, want %v", lt.typ, lt.rcvr, gc, lt.gc)
+			}
+			if !bytes.Equal(inRegs, lt.inRegs) {
+				t.Errorf("funcLayout(%v, %v).inRegs=%v, want %v", lt.typ, lt.rcvr, inRegs, lt.inRegs)
+			}
+			if !bytes.Equal(outRegs, lt.outRegs) {
+				t.Errorf("funcLayout(%v, %v).outRegs=%v, want %v", lt.typ, lt.rcvr, outRegs, lt.outRegs)
+			}
+			if ptrs && len(stack) == 0 || !ptrs && len(stack) > 0 {
+				t.Errorf("funcLayout(%v, %v) pointers flag=%v, want %v", lt.typ, lt.rcvr, ptrs, !ptrs)
+			}
+		})
 	}
 }
 
+*/
+
 func verifyGCBits(t *testing.T, typ Type, bits []byte) {
 	heapBits := GCBits(New(typ).Interface())
 	if !bytes.Equal(heapBits, bits) {
@@ -6861,21 +6984,6 @@ func TestExported(t *testing.T) {
 }
 */
 
-type embed struct {
-	EmbedWithUnexpMeth
-}
-
-/*
-func TestNameBytesAreAligned(t *testing.T) {
-	typ := TypeOf(embed{})
-	b := FirstMethodNameBytes(typ)
-	v := uintptr(unsafe.Pointer(b))
-	if v%unsafe.Alignof((*byte)(nil)) != 0 {
-		t.Errorf("reflect.name.bytes pointer is not aligned: %x", v)
-	}
-}
-*/
-
 func TestTypeStrings(t *testing.T) {
 	type stringTest struct {
 		typ  Type
@@ -7215,3 +7323,13 @@ func iterateToString(it *MapIter) string {
 	sort.Strings(got)
 	return "[" + strings.Join(got, ", ") + "]"
 }
+
+func TestConvertibleTo(t *testing.T) {
+	t1 := ValueOf(example1.MyStruct{}).Type()
+	t2 := ValueOf(example2.MyStruct{}).Type()
+
+	// Shouldn't raise stack overflow
+	if t1.ConvertibleTo(t2) {
+		t.Fatalf("(%s).ConvertibleTo(%s) = true, want false", t1, t2)
+	}
+}
diff --git a/libgo/go/reflect/internal/example1/example.go b/libgo/go/reflect/internal/example1/example.go
new file mode 100644
index 0000000..0f829a8
--- /dev/null
+++ b/libgo/go/reflect/internal/example1/example.go
@@ -0,0 +1,6 @@
+package example1
+
+type MyStruct struct {
+	MyStructs []MyStruct
+	MyStruct  *MyStruct
+}
diff --git a/libgo/go/reflect/internal/example2/example.go b/libgo/go/reflect/internal/example2/example.go
new file mode 100644
index 0000000..df64ba1
--- /dev/null
+++ b/libgo/go/reflect/internal/example2/example.go
@@ -0,0 +1,6 @@
+package example2
+
+type MyStruct struct {
+	MyStructs []MyStruct
+	MyStruct  *MyStruct
+}
diff --git a/libgo/go/reflect/type.go b/libgo/go/reflect/type.go
index c05ec68..0c394a2 100644
--- a/libgo/go/reflect/type.go
+++ b/libgo/go/reflect/type.go
@@ -108,9 +108,15 @@ type Type interface {
 	AssignableTo(u Type) bool
 
 	// ConvertibleTo reports whether a value of the type is convertible to type u.
+	// Even if ConvertibleTo returns true, the conversion may still panic.
+	// For example, a slice of type []T is convertible to *[N]T,
+	// but the conversion will panic if its length is less than N.
 	ConvertibleTo(u Type) bool
 
 	// Comparable reports whether values of this type are comparable.
+	// Even if Comparable returns true, the comparison may still panic.
+	// For example, values of interface type are comparable,
+	// but the comparison will panic if their dynamic type is not comparable.
 	Comparable() bool
 
 	// Methods applicable only to some types, depending on Kind.
@@ -224,7 +230,7 @@ type Type interface {
 // See https://golang.org/issue/4876 for more details.
 
 /*
- * These data structures are known to the compiler (../../cmd/internal/gc/reflect.go).
+ * These data structures are known to the compiler (../../cmd/internal/reflectdata/reflect.go).
  * A few are known to ../runtime/type.go to convey to debuggers.
  * They are also known to ../runtime/type.go.
  */
@@ -419,12 +425,13 @@ type structType struct {
 // Method represents a single method.
 type Method struct {
 	// Name is the method name.
+	Name string
+
 	// PkgPath is the package path that qualifies a lower case (unexported)
 	// method name. It is empty for upper case (exported) method names.
 	// The combination of PkgPath and Name uniquely identifies a method
 	// in a method set.
 	// See https://golang.org/ref/spec#Uniqueness_of_identifiers
-	Name    string
 	PkgPath string
 
 	Type  Type  // method type
@@ -432,6 +439,11 @@ type Method struct {
 	Index int   // index for Type.Method
 }
 
+// IsExported reports whether the method is exported.
+func (m Method) IsExported() bool {
+	return m.PkgPath == ""
+}
+
 const (
 	kindDirectIface = 1 << 5
 	kindGCProg      = 1 << 6 // Type.gc points to GC program
@@ -828,6 +840,7 @@ func (t *interfaceType) MethodByName(name string) (m Method, ok bool) {
 type StructField struct {
 	// Name is the field name.
 	Name string
+
 	// PkgPath is the package path that qualifies a lower case (unexported)
 	// field name. It is empty for upper case (exported) field names.
 	// See https://golang.org/ref/spec#Uniqueness_of_identifiers
@@ -840,6 +853,11 @@ type StructField struct {
 	Anonymous bool      // is an embedded field
 }
 
+// IsExported reports whether the field is exported.
+func (f StructField) IsExported() bool {
+	return f.PkgPath == ""
+}
+
 // A StructTag is the tag string in a struct field.
 //
 // By convention, tag strings are a concatenation of
@@ -1300,7 +1318,7 @@ func haveIdenticalType(T, V Type, cmpTags bool) bool {
 		return T == V
 	}
 
-	if T.Name() != V.Name() || T.Kind() != V.Kind() {
+	if T.Name() != V.Name() || T.Kind() != V.Kind() || T.PkgPath() != V.PkgPath() {
 		return false
 	}
 
@@ -1529,7 +1547,7 @@ func MapOf(key, elem Type) Type {
 
 	// Make a map type.
 	// Note: flag values must match those used in the TMAP case
-	// in ../cmd/compile/internal/gc/reflect.go:dtypesym.
+	// in ../cmd/compile/internal/reflectdata/reflect.go:writeType.
 	var imap interface{} = (map[unsafe.Pointer]unsafe.Pointer)(nil)
 	mt := **(**mapType)(unsafe.Pointer(&imap))
 	mt.string = &s
@@ -2257,8 +2275,7 @@ func runtimeStructField(field StructField) (structField, string) {
 		panic("reflect.StructOf: field \"" + field.Name + "\" is anonymous but has PkgPath set")
 	}
 
-	exported := field.PkgPath == ""
-	if exported {
+	if field.IsExported() {
 		// Best-effort check for misuse.
 		// Since this field will be treated as exported, not much harm done if Unicode lowercase slips through.
 		c := field.Name[0]
@@ -2298,7 +2315,7 @@ func runtimeStructField(field StructField) (structField, string) {
 
 // typeptrdata returns the length in bytes of the prefix of t
 // containing pointer data. Anything after this offset is scalar data.
-// keep in sync with ../cmd/compile/internal/gc/reflect.go
+// keep in sync with ../cmd/compile/internal/reflectdata/reflect.go
 func typeptrdata(t *rtype) uintptr {
 	switch t.Kind() {
 	case Struct:
@@ -2322,25 +2339,29 @@ func typeptrdata(t *rtype) uintptr {
 	}
 }
 
-// See cmd/compile/internal/gc/reflect.go for derivation of constant.
+// See cmd/compile/internal/reflectdata/reflect.go for derivation of constant.
 const maxPtrmaskBytes = 2048
 
-// ArrayOf returns the array type with the given count and element type.
+// ArrayOf returns the array type with the given length and element type.
 // For example, if t represents int, ArrayOf(5, t) represents [5]int.
 //
 // If the resulting type would be larger than the available address space,
 // ArrayOf panics.
-func ArrayOf(count int, elem Type) Type {
+func ArrayOf(length int, elem Type) Type {
+	if length < 0 {
+		panic("reflect: negative length passed to ArrayOf")
+	}
+
 	typ := elem.(*rtype)
 
 	// Look in cache.
-	ckey := cacheKey{Array, typ, nil, uintptr(count)}
+	ckey := cacheKey{Array, typ, nil, uintptr(length)}
 	if array, ok := lookupCache.Load(ckey); ok {
 		return array.(Type)
 	}
 
 	// Look in known types.
-	s := "[" + strconv.Itoa(count) + "]" + *typ.string
+	s := "[" + strconv.Itoa(length) + "]" + *typ.string
 	if tt := lookupType(s); tt != nil {
 		array := (*arrayType)(unsafe.Pointer(toType(tt).(*rtype)))
 		if array.elem == typ {
@@ -2358,28 +2379,27 @@ func ArrayOf(count int, elem Type) Type {
 
 	// gccgo uses a different hash.
 	// array.hash = fnv1(typ.hash, '[')
-	// for n := uint32(count); n > 0; n >>= 8 {
+	// for n := uint32(length); n > 0; n >>= 8 {
 	// 	array.hash = fnv1(array.hash, byte(n))
 	// }
 	// array.hash = fnv1(array.hash, ']')
 	array.hash = typ.hash + 1 + 13
-
 	array.elem = typ
 	array.ptrToThis = nil
 	if typ.size > 0 {
 		max := ^uintptr(0) / typ.size
-		if uintptr(count) > max {
+		if uintptr(length) > max {
 			panic("reflect.ArrayOf: array size would exceed virtual address space")
 		}
 	}
-	array.size = typ.size * uintptr(count)
-	if count > 0 && typ.ptrdata != 0 {
-		array.ptrdata = typ.size*uintptr(count-1) + typ.ptrdata
+	array.size = typ.size * uintptr(length)
+	if length > 0 && typ.ptrdata != 0 {
+		array.ptrdata = typ.size*uintptr(length-1) + typ.ptrdata
 	}
 	array.align = typ.align
 	array.fieldAlign = typ.fieldAlign
 	array.uncommonType = nil
-	array.len = uintptr(count)
+	array.len = uintptr(length)
 	array.slice = SliceOf(elem).(*rtype)
 
 	switch {
@@ -2388,7 +2408,7 @@ func ArrayOf(count int, elem Type) Type {
 		array.gcdata = nil
 		array.ptrdata = 0
 
-	case count == 1:
+	case length == 1:
 		// In memory, 1-element array looks just like the element.
 		array.kind |= typ.kind & kindGCProg
 		array.gcdata = typ.gcdata
@@ -2397,7 +2417,7 @@ func ArrayOf(count int, elem Type) Type {
 	case typ.kind&kindGCProg == 0 && array.size <= maxPtrmaskBytes*8*ptrSize:
 		// Element is small with pointer mask; array is still small.
 		// Create direct pointer mask by turning each 1 bit in elem
-		// into count 1 bits in larger mask.
+		// into length 1 bits in larger mask.
 		mask := make([]byte, (array.ptrdata/ptrSize+7)/8)
 		emitGCMask(mask, 0, typ, array.len)
 		array.gcdata = &mask[0]
@@ -2418,14 +2438,14 @@ func ArrayOf(count int, elem Type) Type {
 				prog = appendVarint(prog, elemWords-elemPtrs-1)
 			}
 		}
-		// Repeat count-1 times.
+		// Repeat length-1 times.
 		if elemWords < 0x80 {
 			prog = append(prog, byte(elemWords|0x80))
 		} else {
 			prog = append(prog, 0x80)
 			prog = appendVarint(prog, elemWords)
 		}
-		prog = appendVarint(prog, uintptr(count)-1)
+		prog = appendVarint(prog, uintptr(length)-1)
 		prog = append(prog, 0)
 		*(*uint32)(unsafe.Pointer(&prog[0])) = uint32(len(prog) - 4)
 		array.kind |= kindGCProg
@@ -2439,9 +2459,9 @@ func ArrayOf(count int, elem Type) Type {
 	array.equal = nil
 	if eequal := etyp.equal; eequal != nil {
 		array.equal = func(p, q unsafe.Pointer) bool {
-			for i := 0; i < count; i++ {
-				pi := arrayAt(p, i, esize, "i < count")
-				qi := arrayAt(q, i, esize, "i < count")
+			for i := 0; i < length; i++ {
+				pi := arrayAt(p, i, esize, "i < length")
+				qi := arrayAt(q, i, esize, "i < length")
 				if !eequal(pi, qi) {
 					return false
 				}
@@ -2451,7 +2471,7 @@ func ArrayOf(count int, elem Type) Type {
 	}
 
 	switch {
-	case count == 1 && !ifaceIndir(typ):
+	case length == 1 && !ifaceIndir(typ):
 		// array of 1 direct iface type can be direct
 		array.kind |= kindDirectIface
 	default:
diff --git a/libgo/go/reflect/value.go b/libgo/go/reflect/value.go
index 0b4f094..300ef1a 100644
--- a/libgo/go/reflect/value.go
+++ b/libgo/go/reflect/value.go
@@ -5,6 +5,7 @@
 package reflect
 
 import (
+	"internal/itoa"
 	"internal/unsafeheader"
 	"math"
 	"runtime"
@@ -350,6 +351,8 @@ func (v Value) CallSlice(in []Value) []Value {
 
 var callGC bool // for testing; see TestCallMethodJump
 
+const debugReflectCall = false
+
 func (v Value) call(op string, in []Value) []Value {
 	// Get function pointer, type.
 	t := (*funcType)(unsafe.Pointer(v.typ))
@@ -372,8 +375,9 @@ func (v Value) call(op string, in []Value) []Value {
 
 	isSlice := op == "CallSlice"
 	n := t.NumIn()
+	isVariadic := t.IsVariadic()
 	if isSlice {
-		if !t.IsVariadic() {
+		if !isVariadic {
 			panic("reflect: CallSlice of non-variadic function")
 		}
 		if len(in) < n {
@@ -383,13 +387,13 @@ func (v Value) call(op string, in []Value) []Value {
 			panic("reflect: CallSlice with too many input arguments")
 		}
 	} else {
-		if t.IsVariadic() {
+		if isVariadic {
 			n--
 		}
 		if len(in) < n {
 			panic("reflect: Call with too few input arguments")
 		}
-		if !t.IsVariadic() && len(in) > n {
+		if !isVariadic && len(in) > n {
 			panic("reflect: Call with too many input arguments")
 		}
 	}
@@ -403,7 +407,7 @@ func (v Value) call(op string, in []Value) []Value {
 			panic("reflect: " + op + " using " + xt.String() + " as type " + targ.String())
 		}
 	}
-	if !isSlice && t.IsVariadic() {
+	if !isSlice && isVariadic {
 		// prepare slice for remaining values
 		m := len(in) - n
 		slice := MakeSlice(t.In(n), m, m)
@@ -857,10 +861,16 @@ func valueInterface(v Value, safe bool) interface{} {
 	return packEface(v)
 }
 
-// InterfaceData returns the interface v's value as a uintptr pair.
+// InterfaceData returns a pair of unspecified uintptr values.
 // It panics if v's Kind is not Interface.
+//
+// In earlier versions of Go, this function returned the interface's
+// value as a uintptr pair. As of Go 1.4, the implementation of
+// interface values precludes any defined use of InterfaceData.
+//
+// Deprecated: The memory representation of interface values is not
+// compatible with InterfaceData.
 func (v Value) InterfaceData() [2]uintptr {
-	// TODO: deprecate this
 	v.mustBe(Interface)
 	// We treat this as a read operation, so we allow
 	// it even for unexported data, because the caller
@@ -2200,9 +2210,14 @@ func New(typ Type) Value {
 		panic("reflect: New(nil)")
 	}
 	t := typ.(*rtype)
+	pt := t.ptrTo()
+	if ifaceIndir(pt) {
+		// This is a pointer to a go:notinheap type.
+		panic("reflect: New of type that may not be allocated in heap (possibly undefined cgo C type)")
+	}
 	ptr := unsafe_New(t)
 	fl := flag(Ptr)
-	return Value{t.ptrTo(), ptr, fl}
+	return Value{pt, ptr, fl}
 }
 
 // NewAt returns a Value representing a pointer to a value of the
@@ -2255,7 +2270,7 @@ func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value
 
 // Convert returns the value v converted to type t.
 // If the usual Go conversion rules do not allow conversion
-// of the value v to type t, Convert panics.
+// of the value v to type t, or if converting v to type t panics, Convert panics.
 func (v Value) Convert(t Type) Value {
 	if v.flag&flagMethod != 0 {
 		v = makeMethodValue("Convert", v)
@@ -2267,6 +2282,26 @@ func (v Value) Convert(t Type) Value {
 	return op(v, t)
 }
 
+// CanConvert reports whether the value v can be converted to type t.
+// If v.CanConvert(t) returns true then v.Convert(t) will not panic.
+func (v Value) CanConvert(t Type) bool {
+	vt := v.Type()
+	if !vt.ConvertibleTo(t) {
+		return false
+	}
+	// Currently the only conversion that is OK in terms of type
+	// but that can panic depending on the value is converting
+	// from slice to pointer-to-array.
+	if vt.Kind() == Slice && t.Kind() == Ptr && t.Elem().Kind() == Array {
+		n := t.Elem().Len()
+		h := (*unsafeheader.Slice)(v.ptr)
+		if n > h.Len {
+			return false
+		}
+	}
+	return true
+}
+
 // convertOp returns the function to convert a value of type src
 // to a value of type dst. If the conversion is illegal, convertOp returns nil.
 func convertOp(dst, src *rtype) func(Value, Type) Value {
@@ -2326,6 +2361,11 @@ func convertOp(dst, src *rtype) func(Value, Type) Value {
 				return cvtRunesString
 			}
 		}
+		// "x is a slice, T is a pointer-to-array type,
+		// and the slice and array types have identical element types."
+		if dst.Kind() == Ptr && dst.Elem().Kind() == Array && src.Elem() == dst.Elem().Elem() {
+			return cvtSliceArrayPtr
+		}
 
 	case Chan:
 		if dst.Kind() == Chan && specialChannelAssignability(dst, src) {
@@ -2519,6 +2559,16 @@ func cvtStringRunes(v Value, t Type) Value {
 	return makeRunes(v.flag.ro(), []rune(v.String()), t)
 }
 
+// convertOp: []T -> *[N]T
+func cvtSliceArrayPtr(v Value, t Type) Value {
+	n := t.Elem().Len()
+	h := (*unsafeheader.Slice)(v.ptr)
+	if n > h.Len {
+		panic("reflect: cannot convert slice with length " + itoa.Itoa(h.Len) + " to pointer to array with length " + itoa.Itoa(n))
+	}
+	return Value{t.common(), h.Data, v.flag&^(flagIndir|flagAddr|flagKindMask) | flag(Ptr)}
+}
+
 // convertOp: direct copy
 func cvtDirect(v Value, typ Type) Value {
 	f := v.flag
diff --git a/libgo/go/reflect/visiblefields.go b/libgo/go/reflect/visiblefields.go
new file mode 100644
index 0000000..1a2b535
--- /dev/null
+++ b/libgo/go/reflect/visiblefields.go
@@ -0,0 +1,105 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflect
+
+// VisibleFields returns all the visible fields in t, which must be a
+// struct type. A field is defined as visible if it's accessible
+// directly with a FieldByName call. The returned fields include fields
+// inside anonymous struct members and unexported fields. They follow
+// the same order found in the struct, with anonymous fields followed
+// immediately by their promoted fields.
+//
+// For each element e of the returned slice, the corresponding field
+// can be retrieved from a value v of type t by calling v.FieldByIndex(e.Index).
+func VisibleFields(t Type) []StructField {
+	if t == nil {
+		panic("reflect: VisibleFields(nil)")
+	}
+	if t.Kind() != Struct {
+		panic("reflect.VisibleFields of non-struct type")
+	}
+	w := &visibleFieldsWalker{
+		byName:   make(map[string]int),
+		visiting: make(map[Type]bool),
+		fields:   make([]StructField, 0, t.NumField()),
+		index:    make([]int, 0, 2),
+	}
+	w.walk(t)
+	// Remove all the fields that have been hidden.
+	// Use an in-place removal that avoids copying in
+	// the common case that there are no hidden fields.
+	j := 0
+	for i := range w.fields {
+		f := &w.fields[i]
+		if f.Name == "" {
+			continue
+		}
+		if i != j {
+			// A field has been removed. We need to shuffle
+			// all the subsequent elements up.
+			w.fields[j] = *f
+		}
+		j++
+	}
+	return w.fields[:j]
+}
+
+type visibleFieldsWalker struct {
+	byName   map[string]int
+	visiting map[Type]bool
+	fields   []StructField
+	index    []int
+}
+
+// walk walks all the fields in the struct type t, visiting
+// fields in index preorder and appending them to w.fields
+// (this maintains the required ordering).
+// Fields that have been overridden have their
+// Name field cleared.
+func (w *visibleFieldsWalker) walk(t Type) {
+	if w.visiting[t] {
+		return
+	}
+	w.visiting[t] = true
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		w.index = append(w.index, i)
+		add := true
+		if oldIndex, ok := w.byName[f.Name]; ok {
+			old := &w.fields[oldIndex]
+			if len(w.index) == len(old.Index) {
+				// Fields with the same name at the same depth
+				// cancel one another out. Set the field name
+				// to empty to signify that has happened, and
+				// there's no need to add this field.
+				old.Name = ""
+				add = false
+			} else if len(w.index) < len(old.Index) {
+				// The old field loses because it's deeper than the new one.
+				old.Name = ""
+			} else {
+				// The old field wins because it's shallower than the new one.
+				add = false
+			}
+		}
+		if add {
+			// Copy the index so that it's not overwritten
+			// by the other appends.
+			f.Index = append([]int(nil), w.index...)
+			w.byName[f.Name] = len(w.fields)
+			w.fields = append(w.fields, f)
+		}
+		if f.Anonymous {
+			if f.Type.Kind() == Ptr {
+				f.Type = f.Type.Elem()
+			}
+			if f.Type.Kind() == Struct {
+				w.walk(f.Type)
+			}
+		}
+		w.index = w.index[:len(w.index)-1]
+	}
+	delete(w.visiting, t)
+}
diff --git a/libgo/go/reflect/visiblefields_test.go b/libgo/go/reflect/visiblefields_test.go
new file mode 100644
index 0000000..915bbee
--- /dev/null
+++ b/libgo/go/reflect/visiblefields_test.go
@@ -0,0 +1,330 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflect_test
+
+import (
+	. "reflect"
+	"testing"
+)
+
+type structField struct {
+	name  string
+	index []int
+}
+
+var fieldsTests = []struct {
+	testName string
+	val      interface{}
+	expect   []structField
+}{{
+	testName: "SimpleStruct",
+	val: struct {
+		A int
+		B string
+		C bool
+	}{},
+	expect: []structField{{
+		name:  "A",
+		index: []int{0},
+	}, {
+		name:  "B",
+		index: []int{1},
+	}, {
+		name:  "C",
+		index: []int{2},
+	}},
+}, {
+	testName: "NonEmbeddedStructMember",
+	val: struct {
+		A struct {
+			X int
+		}
+	}{},
+	expect: []structField{{
+		name:  "A",
+		index: []int{0},
+	}},
+}, {
+	testName: "EmbeddedExportedStruct",
+	val: struct {
+		SFG
+	}{},
+	expect: []structField{{
+		name:  "SFG",
+		index: []int{0},
+	}, {
+		name:  "F",
+		index: []int{0, 0},
+	}, {
+		name:  "G",
+		index: []int{0, 1},
+	}},
+}, {
+	testName: "EmbeddedUnexportedStruct",
+	val: struct {
+		sFG
+	}{},
+	expect: []structField{{
+		name:  "sFG",
+		index: []int{0},
+	}, {
+		name:  "F",
+		index: []int{0, 0},
+	}, {
+		name:  "G",
+		index: []int{0, 1},
+	}},
+}, {
+	testName: "TwoEmbeddedStructsWithCancellingMembers",
+	val: struct {
+		SFG
+		SF
+	}{},
+	expect: []structField{{
+		name:  "SFG",
+		index: []int{0},
+	}, {
+		name:  "G",
+		index: []int{0, 1},
+	}, {
+		name:  "SF",
+		index: []int{1},
+	}},
+}, {
+	testName: "EmbeddedStructsWithSameFieldsAtDifferentDepths",
+	val: struct {
+		SFGH3
+		SG1
+		SFG2
+		SF2
+		L int
+	}{},
+	expect: []structField{{
+		name:  "SFGH3",
+		index: []int{0},
+	}, {
+		name:  "SFGH2",
+		index: []int{0, 0},
+	}, {
+		name:  "SFGH1",
+		index: []int{0, 0, 0},
+	}, {
+		name:  "SFGH",
+		index: []int{0, 0, 0, 0},
+	}, {
+		name:  "H",
+		index: []int{0, 0, 0, 0, 2},
+	}, {
+		name:  "SG1",
+		index: []int{1},
+	}, {
+		name:  "SG",
+		index: []int{1, 0},
+	}, {
+		name:  "G",
+		index: []int{1, 0, 0},
+	}, {
+		name:  "SFG2",
+		index: []int{2},
+	}, {
+		name:  "SFG1",
+		index: []int{2, 0},
+	}, {
+		name:  "SFG",
+		index: []int{2, 0, 0},
+	}, {
+		name:  "SF2",
+		index: []int{3},
+	}, {
+		name:  "SF1",
+		index: []int{3, 0},
+	}, {
+		name:  "SF",
+		index: []int{3, 0, 0},
+	}, {
+		name:  "L",
+		index: []int{4},
+	}},
+}, {
+	testName: "EmbeddedPointerStruct",
+	val: struct {
+		*SF
+	}{},
+	expect: []structField{{
+		name:  "SF",
+		index: []int{0},
+	}, {
+		name:  "F",
+		index: []int{0, 0},
+	}},
+}, {
+	testName: "EmbeddedNotAPointer",
+	val: struct {
+		M
+	}{},
+	expect: []structField{{
+		name:  "M",
+		index: []int{0},
+	}},
+}, {
+	testName: "RecursiveEmbedding",
+	val:      Rec1{},
+	expect: []structField{{
+		name:  "Rec2",
+		index: []int{0},
+	}, {
+		name:  "F",
+		index: []int{0, 0},
+	}, {
+		name:  "Rec1",
+		index: []int{0, 1},
+	}},
+}, {
+	testName: "RecursiveEmbedding2",
+	val:      Rec2{},
+	expect: []structField{{
+		name:  "F",
+		index: []int{0},
+	}, {
+		name:  "Rec1",
+		index: []int{1},
+	}, {
+		name:  "Rec2",
+		index: []int{1, 0},
+	}},
+}, {
+	testName: "RecursiveEmbedding3",
+	val:      RS3{},
+	expect: []structField{{
+		name:  "RS2",
+		index: []int{0},
+	}, {
+		name:  "RS1",
+		index: []int{1},
+	}, {
+		name:  "i",
+		index: []int{1, 0},
+	}},
+}}
+
+type SFG struct {
+	F int
+	G int
+}
+
+type SFG1 struct {
+	SFG
+}
+
+type SFG2 struct {
+	SFG1
+}
+
+type SFGH struct {
+	F int
+	G int
+	H int
+}
+
+type SFGH1 struct {
+	SFGH
+}
+
+type SFGH2 struct {
+	SFGH1
+}
+
+type SFGH3 struct {
+	SFGH2
+}
+
+type SF struct {
+	F int
+}
+
+type SF1 struct {
+	SF
+}
+
+type SF2 struct {
+	SF1
+}
+
+type SG struct {
+	G int
+}
+
+type SG1 struct {
+	SG
+}
+
+type sFG struct {
+	F int
+	G int
+}
+
+type RS1 struct {
+	i int
+}
+
+type RS2 struct {
+	RS1
+}
+
+type RS3 struct {
+	RS2
+	RS1
+}
+
+type M map[string]interface{}
+
+type Rec1 struct {
+	*Rec2
+}
+
+type Rec2 struct {
+	F string
+	*Rec1
+}
+
+func TestFields(t *testing.T) {
+	for _, test := range fieldsTests {
+		test := test
+		t.Run(test.testName, func(t *testing.T) {
+			typ := TypeOf(test.val)
+			fields := VisibleFields(typ)
+			if got, want := len(fields), len(test.expect); got != want {
+				t.Fatalf("unexpected field count; got %d want %d", got, want)
+			}
+
+			for j, field := range fields {
+				expect := test.expect[j]
+				t.Logf("field %d: %s", j, expect.name)
+				gotField := typ.FieldByIndex(field.Index)
+				// Unfortunately, FieldByIndex does not return
+				// a field with the same index that we passed in,
+				// so we set it to the expected value so that
+				// it can be compared later with the result of FieldByName.
+				gotField.Index = field.Index
+				expectField := typ.FieldByIndex(expect.index)
+				// ditto.
+				expectField.Index = expect.index
+				if !DeepEqual(gotField, expectField) {
+					t.Fatalf("unexpected field result\ngot %#v\nwant %#v", gotField, expectField)
+				}
+
+				// Sanity check that we can actually access the field by the
+				// expected name.
+				gotField1, ok := typ.FieldByName(expect.name)
+				if !ok {
+					t.Fatalf("field %q not accessible by name", expect.name)
+				}
+				if !DeepEqual(gotField1, expectField) {
+					t.Fatalf("unexpected FieldByName result; got %#v want %#v", gotField1, expectField)
+				}
+			}
+		})
+	}
+}