diff --git a/internal/lib/fmt/print.go b/internal/lib/fmt/print.go
index d3368b85..88786f0a 100644
--- a/internal/lib/fmt/print.go
+++ b/internal/lib/fmt/print.go
@@ -777,13 +777,10 @@ func (p *pp) printArg(arg any, verb rune) {
 func (p *pp) printValue(value reflect.Value, verb rune, depth int) {
 	// Handle values with special methods if not already handled by printArg (depth == 0).
 	if depth > 0 && value.IsValid() && value.CanInterface() {
-		/* TODO(xsw):
 		p.arg = value.Interface()
 		if p.handleMethods(verb) {
 			return
 		}
-		*/
-		panic("todo: fmt.(*pp).printValue - handleMethods")
 	}
 	p.arg = nil
 	p.value = value
diff --git a/internal/lib/internal/reflectlite/type.go b/internal/lib/internal/reflectlite/type.go
index e1670162..8e06a915 100644
--- a/internal/lib/internal/reflectlite/type.go
+++ b/internal/lib/internal/reflectlite/type.go
@@ -157,7 +157,7 @@ func (t rtype) NumMethod() int {
 		}
 		return len(t.exportedMethods())
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.NumMethod")
 }
 
 func (t rtype) PkgPath() string {
@@ -171,7 +171,7 @@ func (t rtype) PkgPath() string {
 		}
 		return t.nameOff(ut.PkgPath).Name()
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.PkgPath")
 }
 
 func (t rtype) Name() string {
@@ -193,7 +193,7 @@ func (t rtype) Name() string {
 		}
 		return s[i+1:]
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.Name")
 }
 
 func toRType(t *abi.Type) rtype {
@@ -220,7 +220,7 @@ func (t rtype) In(i int) Type {
 		}
 		return toType(tt.InSlice()[i])
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.In")
 }
 
 func (t rtype) Key() Type {
@@ -255,7 +255,7 @@ func (t rtype) NumIn() int {
 		}
 		return int(tt.InCount)
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.NumIn")
 }
 
 func (t rtype) NumOut() int {
@@ -266,7 +266,7 @@ func (t rtype) NumOut() int {
 		}
 		return tt.NumOut()
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.NumOut")
 }
 
 func (t rtype) Out(i int) Type {
@@ -277,7 +277,7 @@ func (t rtype) Out(i int) Type {
 		}
 		return toType(tt.OutSlice()[i])
 	*/
-	panic("todo")
+	panic("todo: reflectlite.rtype.Out")
 }
 
 // add returns p+x.
@@ -408,7 +408,7 @@ func implements(T, V *abi.Type) bool {
 		}
 		return false
 	*/
-	panic("todo")
+	panic("todo: reflectlite.implements")
 }
 
 // directlyAssignable reports whether a value x of type V can be directly
@@ -544,7 +544,7 @@ func haveIdenticalUnderlyingType(T, V *abi.Type, cmpTags bool) bool {
 
 		return false
 	*/
-	panic("todo")
+	panic("todo: reflectlite.haveIdenticalUnderlyingType")
 }
 
 // toType converts from a *rtype to a Type that can be returned
diff --git a/internal/lib/internal/reflectlite/value.go b/internal/lib/internal/reflectlite/value.go
index d986048a..9bbd5e47 100644
--- a/internal/lib/internal/reflectlite/value.go
+++ b/internal/lib/internal/reflectlite/value.go
@@ -98,7 +98,7 @@ func (v Value) pointer() unsafe.Pointer {
 		}
 		return v.ptr
 	*/
-	panic("todo")
+	panic("todo: reflectlite.Value.pointer")
 }
 
 // packEface converts v to the empty interface.
@@ -263,7 +263,7 @@ func (v Value) Elem() Value {
 		}
 		panic(&ValueError{"reflectlite.Value.Elem", v.kind()})
 	*/
-	panic("todo")
+	panic("todo: reflectlite.Value.Elem")
 }
 
 func valueInterface(v Value) any {
@@ -367,7 +367,7 @@ func (v Value) numMethod() int {
 		}
 		return v.typ.NumMethod()
 	*/
-	panic("todo")
+	panic("todo: reflectlite.Value.numMethod")
 }
 
 // Set assigns x to the value v.
@@ -455,7 +455,7 @@ func (v Value) assignTo(context string, dst *abi.Type, target unsafe.Pointer) Va
 	// Failed.
 	// TODO(xsw):
 	// panic(context + ": value of type " + toRType(v.typ).String() + " is not assignable to type " + toRType(dst).String())
-	panic("todo")
+	panic("todo: reflectlite.Value.assignTo")
 }
 
 // arrayAt returns the i-th element of p,
diff --git a/internal/lib/os/file.go b/internal/lib/os/file.go
index a522f7f3..a48f759b 100644
--- a/internal/lib/os/file.go
+++ b/internal/lib/os/file.go
@@ -87,7 +87,7 @@ func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
 		}
 		return
 	*/
-	panic("todo")
+	panic("todo: os.File.ReadAt")
 }
 
 // ReadFrom implements io.ReaderFrom.
@@ -102,7 +102,7 @@ func (f *File) ReadFrom(r io.Reader) (n int64, err error) {
 		}
 		return n, f.wrapErr("write", e)
 	*/
-	panic("todo")
+	panic("todo: os.File.ReadFrom")
 }
 
 func genericReadFrom(f *File, r io.Reader) (int64, error) {
diff --git a/internal/lib/reflect/makefunc.go b/internal/lib/reflect/makefunc.go
index 2a0e6208..cdc48840 100644
--- a/internal/lib/reflect/makefunc.go
+++ b/internal/lib/reflect/makefunc.go
@@ -146,7 +146,7 @@ func makeMethodValue(op string, v Value) Value {
 
 		return Value{ftyp.Common(), unsafe.Pointer(fv), v.flag&flagRO | flag(Func)}
 	*/
-	panic("todo")
+	panic("todo: reflect.makeMethodValue")
 }
 
 /*
diff --git a/internal/lib/reflect/type.go b/internal/lib/reflect/type.go
index 8dfce54a..68b3c93b 100644
--- a/internal/lib/reflect/type.go
+++ b/internal/lib/reflect/type.go
@@ -461,7 +461,7 @@ func (t *rtype) NumMethod() int {
 		}
 		return len(t.exportedMethods())
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.NumMethod")
 }
 
 func (t *rtype) Method(i int) (m Method) {
@@ -498,7 +498,7 @@ func (t *rtype) Method(i int) (m Method) {
 		m.Index = i
 		return m
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.Method")
 }
 
 func (t *rtype) MethodByName(name string) (m Method, ok bool) {
@@ -533,7 +533,7 @@ func (t *rtype) MethodByName(name string) (m Method, ok bool) {
 
 		return Method{}, false
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.MethodByName")
 }
 
 func (t *rtype) PkgPath() string {
@@ -570,7 +570,7 @@ func (t *rtype) Name() string {
 		}
 		return s[i+1:]
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.Name")
 }
 
 func nameFor(t *abi.Type) string {
@@ -596,7 +596,7 @@ func elem(t *abi.Type) *abi.Type {
 	}
 	// TODO(xsw):
 	// panic("reflect: Elem of invalid type " + stringFor(t))
-	panic("todo")
+	panic("todo: reflect.elem")
 }
 
 func (t *rtype) Elem() Type {
@@ -611,7 +611,7 @@ func (t *rtype) Field(i int) StructField {
 		tt := (*structType)(unsafe.Pointer(t))
 		return tt.Field(i)
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.Field")
 }
 
 func (t *rtype) FieldByIndex(index []int) StructField {
@@ -622,7 +622,7 @@ func (t *rtype) FieldByIndex(index []int) StructField {
 		tt := (*structType)(unsafe.Pointer(t))
 		return tt.FieldByIndex(index)
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.FieldByIndex")
 }
 
 func (t *rtype) FieldByName(name string) (StructField, bool) {
@@ -633,7 +633,7 @@ func (t *rtype) FieldByName(name string) (StructField, bool) {
 		tt := (*structType)(unsafe.Pointer(t))
 		return tt.FieldByName(name)
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.FieldByName")
 }
 
 func (t *rtype) FieldByNameFunc(match func(string) bool) (StructField, bool) {
@@ -644,7 +644,7 @@ func (t *rtype) FieldByNameFunc(match func(string) bool) (StructField, bool) {
 		tt := (*structType)(unsafe.Pointer(t))
 		return tt.FieldByNameFunc(match)
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.FieldByNameFunc")
 }
 
 func (t *rtype) Key() Type {
@@ -679,7 +679,7 @@ func (t *rtype) In(i int) Type {
 		tt := (*abi.FuncType)(unsafe.Pointer(t))
 		return toType(tt.InSlice()[i])
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.In")
 }
 
 func (t *rtype) NumIn() int {
@@ -690,7 +690,7 @@ func (t *rtype) NumIn() int {
 		tt := (*abi.FuncType)(unsafe.Pointer(t))
 		return tt.NumIn()
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.NumIn")
 }
 
 func (t *rtype) NumOut() int {
@@ -701,7 +701,7 @@ func (t *rtype) NumOut() int {
 		tt := (*abi.FuncType)(unsafe.Pointer(t))
 		return tt.NumOut()
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.NumOut")
 }
 
 func (t *rtype) Out(i int) Type {
@@ -712,7 +712,7 @@ func (t *rtype) Out(i int) Type {
 		tt := (*abi.FuncType)(unsafe.Pointer(t))
 		return toType(tt.OutSlice()[i])
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.Out")
 }
 
 func (t *rtype) IsVariadic() bool {
@@ -723,7 +723,7 @@ func (t *rtype) IsVariadic() bool {
 		tt := (*abi.FuncType)(unsafe.Pointer(t))
 		return tt.IsVariadic()
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.IsVariadic")
 }
 
 // add returns p+x.
@@ -916,7 +916,7 @@ func (t *rtype) ptrTo() *abi.Type {
 		pi, _ := ptrMap.LoadOrStore(t, &pp)
 		return &pi.(*ptrType).Type
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.ptrTo")
 }
 
 func ptrTo(t *abi.Type) *abi.Type {
@@ -942,7 +942,7 @@ func (t *rtype) Implements(u Type) bool {
 		}
 		return implements(u.common(), t.common())
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.Implements")
 }
 
 func (t *rtype) AssignableTo(u Type) bool {
@@ -953,7 +953,7 @@ func (t *rtype) AssignableTo(u Type) bool {
 		uu := u.common()
 		return directlyAssignable(uu, t.common()) || implements(uu, t.common())
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.AssignableTo")
 }
 
 func (t *rtype) ConvertibleTo(u Type) bool {
@@ -963,7 +963,7 @@ func (t *rtype) ConvertibleTo(u Type) bool {
 		}
 		return convertOp(u.common(), t.common()) != nil
 	*/
-	panic("todo")
+	panic("todo: reflect.rtype.ConvertibleTo")
 }
 
 func (t *rtype) Comparable() bool {
@@ -1055,7 +1055,7 @@ func implements(T, V *abi.Type) bool {
 		}
 		return false
 	*/
-	panic("todo")
+	panic("todo: reflect.implements")
 }
 
 // specialChannelAssignability reports whether a value x of channel type V
@@ -1070,7 +1070,7 @@ func specialChannelAssignability(T, V *abi.Type) bool {
 		// and at least one of V or T is not a defined type.
 		return V.ChanDir() == abi.BothDir && (nameFor(T) == "" || nameFor(V) == "") && haveIdenticalType(T.Elem(), V.Elem(), true)
 	*/
-	panic("todo")
+	panic("todo: reflect.specialChannelAssignability")
 }
 
 // directlyAssignable reports whether a value x of type V can be directly
@@ -1202,7 +1202,7 @@ func haveIdenticalUnderlyingType(T, V *abi.Type, cmpTags bool) bool {
 
 		return false
 	*/
-	panic("todo")
+	panic("todo: reflect.haveIdenticalUnderlyingType")
 }
 
 // SliceOf returns the slice type with element type t.
diff --git a/internal/lib/reflect/value.go b/internal/lib/reflect/value.go
index 205cf5c3..7e5f8c60 100644
--- a/internal/lib/reflect/value.go
+++ b/internal/lib/reflect/value.go
@@ -128,7 +128,7 @@ func (v Value) pointer() unsafe.Pointer {
 		}
 		return v.ptr
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.pointer")
 }
 
 // packEface converts v to the empty interface.
@@ -355,7 +355,7 @@ func (v Value) bytesSlow() []byte {
 		}
 		panic(&ValueError{"reflect.Value.Bytes", v.kind()})
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.byteSlow")
 }
 
 // runes returns v's underlying value.
@@ -776,7 +776,7 @@ func valueInterface(v Value, safe bool) any {
 		// TODO: pass safe to packEface so we don't need to copy if safe==true?
 		return packEface(v)
 	*/
-	panic("todo")
+	panic("todo: reflect.valueInterface")
 }
 
 // InterfaceData returns a pair of unspecified uintptr values.
@@ -800,7 +800,7 @@ func (v Value) InterfaceData() [2]uintptr {
 		// Interface value is always bigger than a word; assume flagIndir.
 		return *(*[2]uintptr)(v.ptr)
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.InterfaceData")
 }
 
 // IsNil reports whether its argument v is nil. The argument must be
@@ -901,7 +901,7 @@ func (v Value) IsZero() bool {
 			panic(&ValueError{"reflect.Value.IsZero", v.Kind()})
 		}
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.IsZero")
 }
 
 // SetZero sets v to be the zero value of v's type.
@@ -958,7 +958,7 @@ func (v Value) SetZero() {
 			panic(&ValueError{"reflect.Value.SetZero", v.Kind()})
 		}
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.SetZero")
 }
 
 // Kind returns v's Kind.
@@ -998,7 +998,7 @@ func (v Value) lenNonSlice() int {
 		}
 		panic(&ValueError{"reflect.Value.Len", v.kind()})
 	*/
-	panic("todo")
+	panic("todo: reflect.Value.lenNonSlice")
 }
 
 // Pointer returns v's value as a uintptr.
@@ -1772,7 +1772,7 @@ func AppendSlice(s, t Value) Value {
 		Copy(s.Slice(ns, ns+nt), t)
 		return s
 	*/
-	panic("todo")
+	panic("todo: reflect.AppendSlice")
 }
 
 // Zero returns a Value representing the zero value for the specified type.
@@ -1819,7 +1819,7 @@ func New(typ Type) Value {
 		fl := flag(Pointer)
 		return Value{pt, ptr, fl}
 	*/
-	panic("todo")
+	panic("todo: reflect.New")
 }
 
 // NewAt returns a Value representing a pointer to a value of the
@@ -1872,7 +1872,7 @@ func (v Value) assignTo(context string, dst *abi.Type, target unsafe.Pointer) Va
 	// Failed.
 	// TODO(xsw):
 	// panic(context + ": value of type " + stringFor(v.typ()) + " is not assignable to type " + stringFor(dst))
-	panic("todo")
+	panic("todo: reflect.Value.assignTo")
 }
 
 // memmove copies size bytes to dst from src. No write barriers are used.