reflect: remove useless parameter from newName

pkgPath always received the empty string. Worse yet, it panicked if it
received anything else. This has been the case ever since newName was
introduced in early 2016.

Change-Id: I5f164305bd30c34455ef35e776c7616f303b37e4
Reviewed-on: https://go-review.googlesource.com/54331
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

src/reflect/export_test.go

@@ -111,7 +111,7 @@ func IsExported(t Type) bool {
 }
 
 func ResolveReflectName(s string) {
-	resolveReflectName(newName(s, "", "", false))
+	resolveReflectName(newName(s, "", false))
 }
 
 type Buffer struct {

src/reflect/type.go

@@ -531,7 +531,7 @@ func round(n, a uintptr) uintptr {
 	return (n + a - 1) &^ (a - 1)
 }
 
-func newName(n, tag, pkgPath string, exported bool) name {
+func newName(n, tag string, exported bool) name {
 	if len(n) > 1<<16-1 {
 		panic("reflect.nameFrom: name too long: " + n)
 	}
@@ -548,9 +548,6 @@ func newName(n, tag, pkgPath string, exported bool) name {
 		l += 2 + len(tag)
 		bits |= 1 << 1
 	}
-	if pkgPath != "" {
-		bits |= 1 << 2
-	}
 
 	b := make([]byte, l)
 	b[0] = bits
@@ -564,10 +561,6 @@ func newName(n, tag, pkgPath string, exported bool) name {
 		copy(tb[2:], tag)
 	}
 
-	if pkgPath != "" {
-		panic("reflect: creating a name with a package path is not supported")
-	}
-
 	return name{bytes: &b[0]}
 }
 
@@ -1436,7 +1429,7 @@ func (t *rtype) ptrTo() *rtype {
 	prototype := *(**ptrType)(unsafe.Pointer(&iptr))
 	pp := *prototype
 
-	pp.str = resolveReflectName(newName(s, "", "", false))
+	pp.str = resolveReflectName(newName(s, "", false))
 	pp.ptrToThis = 0
 
 	// For the type structures linked into the binary, the
@@ -1849,7 +1842,7 @@ func ChanOf(dir ChanDir, t Type) Type {
 	ch := *prototype
 	ch.tflag = 0
 	ch.dir = uintptr(dir)
-	ch.str = resolveReflectName(newName(s, "", "", false))
+	ch.str = resolveReflectName(newName(s, "", false))
 	ch.hash = fnv1(typ.hash, 'c', byte(dir))
 	ch.elem = typ
 
@@ -1892,7 +1885,7 @@ func MapOf(key, elem Type) Type {
 	// Make a map type.
 	var imap interface{} = (map[unsafe.Pointer]unsafe.Pointer)(nil)
 	mt := **(**mapType)(unsafe.Pointer(&imap))
-	mt.str = resolveReflectName(newName(s, "", "", false))
+	mt.str = resolveReflectName(newName(s, "", false))
 	mt.tflag = 0
 	mt.hash = fnv1(etyp.hash, 'm', byte(ktyp.hash>>24), byte(ktyp.hash>>16), byte(ktyp.hash>>8), byte(ktyp.hash))
 	mt.key = ktyp
@@ -2060,7 +2053,7 @@ func FuncOf(in, out []Type, variadic bool) Type {
 	}
 
 	// Populate the remaining fields of ft and store in cache.
-	ft.str = resolveReflectName(newName(str, "", "", false))
+	ft.str = resolveReflectName(newName(str, "", false))
 	ft.ptrToThis = 0
 	return addToCache(&ft.rtype)
 }
@@ -2255,7 +2248,7 @@ func bucketOf(ktyp, etyp *rtype) *rtype {
 		b.align = 8
 	}
 	s := "bucket(" + ktyp.String() + "," + etyp.String() + ")"
-	b.str = resolveReflectName(newName(s, "", "", false))
+	b.str = resolveReflectName(newName(s, "", false))
 	return b
 }
 
@@ -2285,7 +2278,7 @@ func SliceOf(t Type) Type {
 	prototype := *(**sliceType)(unsafe.Pointer(&islice))
 	slice := *prototype
 	slice.tflag = 0
-	slice.str = resolveReflectName(newName(s, "", "", false))
+	slice.str = resolveReflectName(newName(s, "", false))
 	slice.hash = fnv1(typ.hash, '[')
 	slice.elem = typ
 	slice.ptrToThis = 0
@@ -2684,7 +2677,7 @@ func StructOf(fields []StructField) Type {
 		}
 	}
 
-	typ.str = resolveReflectName(newName(str, "", "", false))
+	typ.str = resolveReflectName(newName(str, "", false))
 	typ.tflag = 0
 	typ.hash = hash
 	typ.size = size
@@ -2813,7 +2806,7 @@ func runtimeStructField(field StructField) structField {
 
 	resolveReflectType(field.Type.common()) // install in runtime
 	return structField{
-		name:       newName(field.Name, string(field.Tag), "", true),
+		name:       newName(field.Name, string(field.Tag), true),
 		typ:        field.Type.common(),
 		offsetAnon: offsetAnon,
 	}
@@ -2877,7 +2870,7 @@ func ArrayOf(count int, elem Type) Type {
 	prototype := *(**arrayType)(unsafe.Pointer(&iarray))
 	array := *prototype
 	array.tflag = 0
-	array.str = resolveReflectName(newName(s, "", "", false))
+	array.str = resolveReflectName(newName(s, "", false))
 	array.hash = fnv1(typ.hash, '[')
 	for n := uint32(count); n > 0; n >>= 8 {
 		array.hash = fnv1(array.hash, byte(n))
@@ -3130,7 +3123,7 @@ func funcLayout(t *rtype, rcvr *rtype) (frametype *rtype, argSize, retOffset uin
 	} else {
 		s = "funcargs(" + t.String() + ")"
 	}
-	x.str = resolveReflectName(newName(s, "", "", false))
+	x.str = resolveReflectName(newName(s, "", false))
 
 	// cache result for future callers
 	framePool = &sync.Pool{New: func() interface{} {