Add Go frontend, libgo library, and Go testsuite.

gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@167407 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 605 insertions, 0 deletions

diff --git a/libgo/go/fmt/scan_test.go b/libgo/go/fmt/scan_test.go
new file mode 100644
index 00000000000..91939320037
--- /dev/null
+++ b/libgo/go/fmt/scan_test.go
@@ -0,0 +1,605 @@
+// Copyright 2009 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 fmt_test
+
+import (
+	"bufio"
+	. "fmt"
+	"io"
+	"os"
+	"reflect"
+	"regexp"
+	"strings"
+	"testing"
+	"utf8"
+)
+
+type ScanTest struct {
+	text string
+	in   interface{}
+	out  interface{}
+}
+
+type ScanfTest struct {
+	format string
+	text   string
+	in     interface{}
+	out    interface{}
+}
+
+type ScanfMultiTest struct {
+	format string
+	text   string
+	in     []interface{}
+	out    []interface{}
+	err    string
+}
+
+var (
+	boolVal              bool
+	intVal               int
+	int8Val              int8
+	int16Val             int16
+	int32Val             int32
+	int64Val             int64
+	uintVal              uint
+	uint8Val             uint8
+	uint16Val            uint16
+	uint32Val            uint32
+	uint64Val            uint64
+	floatVal             float
+	float32Val           float32
+	float64Val           float64
+	stringVal            string
+	stringVal1           string
+	bytesVal             []byte
+	complexVal           complex
+	complex64Val         complex64
+	complex128Val        complex128
+	renamedBoolVal       renamedBool
+	renamedIntVal        renamedInt
+	renamedInt8Val       renamedInt8
+	renamedInt16Val      renamedInt16
+	renamedInt32Val      renamedInt32
+	renamedInt64Val      renamedInt64
+	renamedUintVal       renamedUint
+	renamedUint8Val      renamedUint8
+	renamedUint16Val     renamedUint16
+	renamedUint32Val     renamedUint32
+	renamedUint64Val     renamedUint64
+	renamedUintptrVal    renamedUintptr
+	renamedStringVal     renamedString
+	renamedBytesVal      renamedBytes
+	renamedFloatVal      renamedFloat
+	renamedFloat32Val    renamedFloat32
+	renamedFloat64Val    renamedFloat64
+	renamedComplexVal    renamedComplex
+	renamedComplex64Val  renamedComplex64
+	renamedComplex128Val renamedComplex128
+)
+
+// Xs accepts any non-empty run of the verb character
+type Xs string
+
+func (x *Xs) Scan(state ScanState, verb int) os.Error {
+	var tok string
+	var c int
+	var err os.Error
+	wid, present := state.Width()
+	if !present {
+		tok, err = state.Token()
+	} else {
+		for i := 0; i < wid; i++ {
+			c, err = state.GetRune()
+			if err != nil {
+				break
+			}
+			tok += string(c)
+		}
+	}
+	if err != nil {
+		return err
+	}
+	if !regexp.MustCompile("^" + string(verb) + "+$").MatchString(tok) {
+		return os.ErrorString("syntax error for xs")
+	}
+	*x = Xs(tok)
+	return nil
+}
+
+var xVal Xs
+
+// myStringReader implements Read but not ReadRune, allowing us to test our readRune wrapper
+// type that creates something that can read runes given only Read().
+type myStringReader struct {
+	r *strings.Reader
+}
+
+func (s *myStringReader) Read(p []byte) (n int, err os.Error) {
+	return s.r.Read(p)
+}
+
+func newReader(s string) *myStringReader {
+	return &myStringReader{strings.NewReader(s)}
+}
+
+var scanTests = []ScanTest{
+	// Numbers
+	{"T\n", &boolVal, true},  // boolean test vals toggle to be sure they are written
+	{"F\n", &boolVal, false}, // restored to zero value
+	{"21\n", &intVal, 21},
+	{"22\n", &int8Val, int8(22)},
+	{"23\n", &int16Val, int16(23)},
+	{"24\n", &int32Val, int32(24)},
+	{"25\n", &int64Val, int64(25)},
+	{"127\n", &int8Val, int8(127)},
+	{"-21\n", &intVal, -21},
+	{"-22\n", &int8Val, int8(-22)},
+	{"-23\n", &int16Val, int16(-23)},
+	{"-24\n", &int32Val, int32(-24)},
+	{"-25\n", &int64Val, int64(-25)},
+	{"-128\n", &int8Val, int8(-128)},
+	{"+21\n", &intVal, +21},
+	{"+22\n", &int8Val, int8(+22)},
+	{"+23\n", &int16Val, int16(+23)},
+	{"+24\n", &int32Val, int32(+24)},
+	{"+25\n", &int64Val, int64(+25)},
+	{"+127\n", &int8Val, int8(+127)},
+	{"26\n", &uintVal, uint(26)},
+	{"27\n", &uint8Val, uint8(27)},
+	{"28\n", &uint16Val, uint16(28)},
+	{"29\n", &uint32Val, uint32(29)},
+	{"30\n", &uint64Val, uint64(30)},
+	{"255\n", &uint8Val, uint8(255)},
+	{"32767\n", &int16Val, int16(32767)},
+	{"2.3\n", &floatVal, 2.3},
+	{"2.3e1\n", &float32Val, float32(2.3e1)},
+	{"2.3e2\n", &float64Val, float64(2.3e2)},
+	{"2.35\n", &stringVal, "2.35"},
+	{"2345678\n", &bytesVal, []byte("2345678")},
+	{"(3.4e1-2i)\n", &complexVal, 3.4e1 - 2i},
+	{"-3.45e1-3i\n", &complex64Val, complex64(-3.45e1 - 3i)},
+	{"-.45e1-1e2i\n", &complex128Val, complex128(-.45e1 - 100i)},
+	{"hello\n", &stringVal, "hello"},
+
+	// Renamed types
+	{"true\n", &renamedBoolVal, renamedBool(true)},
+	{"F\n", &renamedBoolVal, renamedBool(false)},
+	{"101\n", &renamedIntVal, renamedInt(101)},
+	{"102\n", &renamedIntVal, renamedInt(102)},
+	{"103\n", &renamedUintVal, renamedUint(103)},
+	{"104\n", &renamedUintVal, renamedUint(104)},
+	{"105\n", &renamedInt8Val, renamedInt8(105)},
+	{"106\n", &renamedInt16Val, renamedInt16(106)},
+	{"107\n", &renamedInt32Val, renamedInt32(107)},
+	{"108\n", &renamedInt64Val, renamedInt64(108)},
+	{"109\n", &renamedUint8Val, renamedUint8(109)},
+	{"110\n", &renamedUint16Val, renamedUint16(110)},
+	{"111\n", &renamedUint32Val, renamedUint32(111)},
+	{"112\n", &renamedUint64Val, renamedUint64(112)},
+	{"113\n", &renamedUintptrVal, renamedUintptr(113)},
+	{"114\n", &renamedStringVal, renamedString("114")},
+	{"115\n", &renamedBytesVal, renamedBytes([]byte("115"))},
+
+	// Custom scanner.
+	{"  vvv ", &xVal, Xs("vvv")},
+
+	// Fixed bugs
+	{"2147483648\n", &int64Val, int64(2147483648)}, // was: integer overflow
+}
+
+var scanfTests = []ScanfTest{
+	{"%v", "TRUE\n", &boolVal, true},
+	{"%t", "false\n", &boolVal, false},
+	{"%v", "-71\n", &intVal, -71},
+	{"%d", "72\n", &intVal, 72},
+	{"%c", "a\n", &intVal, 'a'},
+	{"%c", "\u5072\n", &intVal, 0x5072},
+	{"%c", "\u1234\n", &intVal, '\u1234'},
+	{"%d", "73\n", &int8Val, int8(73)},
+	{"%d", "+74\n", &int16Val, int16(74)},
+	{"%d", "75\n", &int32Val, int32(75)},
+	{"%d", "76\n", &int64Val, int64(76)},
+	{"%b", "1001001\n", &intVal, 73},
+	{"%o", "075\n", &intVal, 075},
+	{"%x", "a75\n", &intVal, 0xa75},
+	{"%v", "71\n", &uintVal, uint(71)},
+	{"%d", "72\n", &uintVal, uint(72)},
+	{"%d", "73\n", &uint8Val, uint8(73)},
+	{"%d", "74\n", &uint16Val, uint16(74)},
+	{"%d", "75\n", &uint32Val, uint32(75)},
+	{"%d", "76\n", &uint64Val, uint64(76)},
+	{"%b", "1001001\n", &uintVal, uint(73)},
+	{"%o", "075\n", &uintVal, uint(075)},
+	{"%x", "a75\n", &uintVal, uint(0xa75)},
+	{"%x", "A75\n", &uintVal, uint(0xa75)},
+
+	// Strings
+	{"%s", "using-%s\n", &stringVal, "using-%s"},
+	{"%x", "7573696e672d2578\n", &stringVal, "using-%x"},
+	{"%q", `"quoted\twith\\do\u0075bl\x65s"` + "\n", &stringVal, "quoted\twith\\doubles"},
+	{"%q", "`quoted with backs`\n", &stringVal, "quoted with backs"},
+
+	// Byte slices
+	{"%s", "bytes-%s\n", &bytesVal, []byte("bytes-%s")},
+	{"%x", "62797465732d2578\n", &bytesVal, []byte("bytes-%x")},
+	{"%q", `"bytes\rwith\vdo\u0075bl\x65s"` + "\n", &bytesVal, []byte("bytes\rwith\vdoubles")},
+	{"%q", "`bytes with backs`\n", &bytesVal, []byte("bytes with backs")},
+
+	// Renamed types
+	{"%v\n", "true\n", &renamedBoolVal, renamedBool(true)},
+	{"%t\n", "F\n", &renamedBoolVal, renamedBool(false)},
+	{"%v", "101\n", &renamedIntVal, renamedInt(101)},
+	{"%c", "\u0101\n", &renamedIntVal, renamedInt('\u0101')},
+	{"%o", "0146\n", &renamedIntVal, renamedInt(102)},
+	{"%v", "103\n", &renamedUintVal, renamedUint(103)},
+	{"%d", "104\n", &renamedUintVal, renamedUint(104)},
+	{"%d", "105\n", &renamedInt8Val, renamedInt8(105)},
+	{"%d", "106\n", &renamedInt16Val, renamedInt16(106)},
+	{"%d", "107\n", &renamedInt32Val, renamedInt32(107)},
+	{"%d", "108\n", &renamedInt64Val, renamedInt64(108)},
+	{"%x", "6D\n", &renamedUint8Val, renamedUint8(109)},
+	{"%o", "0156\n", &renamedUint16Val, renamedUint16(110)},
+	{"%d", "111\n", &renamedUint32Val, renamedUint32(111)},
+	{"%d", "112\n", &renamedUint64Val, renamedUint64(112)},
+	{"%d", "113\n", &renamedUintptrVal, renamedUintptr(113)},
+	{"%s", "114\n", &renamedStringVal, renamedString("114")},
+	{"%q", "\"1155\"\n", &renamedBytesVal, renamedBytes([]byte("1155"))},
+	{"%g", "115.1\n", &renamedFloatVal, renamedFloat(115.1)},
+	{"%g", "116e1\n", &renamedFloat32Val, renamedFloat32(116e1)},
+	{"%g", "-11.7e+1", &renamedFloat64Val, renamedFloat64(-11.7e+1)},
+	{"%g", "11+5.1i\n", &renamedComplexVal, renamedComplex(11 + 5.1i)},
+	{"%g", "11+6e1i\n", &renamedComplex64Val, renamedComplex64(11 + 6e1i)},
+	{"%g", "-11.+7e+1i", &renamedComplex128Val, renamedComplex128(-11. + 7e+1i)},
+
+	// Interesting formats
+	{"here is\tthe value:%d", "here is   the\tvalue:118\n", &intVal, 118},
+	{"%% %%:%d", "% %:119\n", &intVal, 119},
+
+	// Corner cases
+	{"%x", "FFFFFFFF\n", &uint32Val, uint32(0xFFFFFFFF)},
+
+	// Custom scanner.
+	{"%s", "  sss ", &xVal, Xs("sss")},
+	{"%2s", "sssss", &xVal, Xs("ss")},
+
+	// Fixed bugs
+	{"%d\n", "27\n", &intVal, 27},  // ok
+	{"%d\n", "28 \n", &intVal, 28}, // was: "unexpected newline"
+}
+
+var overflowTests = []ScanTest{
+	{"128", &int8Val, 0},
+	{"32768", &int16Val, 0},
+	{"-129", &int8Val, 0},
+	{"-32769", &int16Val, 0},
+	{"256", &uint8Val, 0},
+	{"65536", &uint16Val, 0},
+	{"1e100", &float32Val, 0},
+	{"1e500", &float64Val, 0},
+	{"(1e100+0i)", &complexVal, 0},
+	{"(1+1e100i)", &complex64Val, 0},
+	{"(1-1e500i)", &complex128Val, 0},
+}
+
+var i, j, k int
+var f float
+var s, t string
+var c complex
+var x, y Xs
+
+var multiTests = []ScanfMultiTest{
+	{"", "", nil, nil, ""},
+	{"%d", "23", args(&i), args(23), ""},
+	{"%2s%3s", "22333", args(&s, &t), args("22", "333"), ""},
+	{"%2d%3d", "44555", args(&i, &j), args(44, 555), ""},
+	{"%2d.%3d", "66.777", args(&i, &j), args(66, 777), ""},
+	{"%d, %d", "23, 18", args(&i, &j), args(23, 18), ""},
+	{"%3d22%3d", "33322333", args(&i, &j), args(333, 333), ""},
+	{"%6vX=%3fY", "3+2iX=2.5Y", args(&c, &f), args((3 + 2i), float(2.5)), ""},
+	{"%d%s", "123abc", args(&i, &s), args(123, "abc"), ""},
+	{"%c%c%c", "2\u50c2X", args(&i, &j, &k), args('2', '\u50c2', 'X'), ""},
+
+	// Custom scanner.
+	{"%2e%f", "eefffff", args(&x, &y), args(Xs("ee"), Xs("fffff")), ""},
+
+	// Errors
+	{"%t", "23 18", args(&i), nil, "bad verb"},
+	{"%d %d %d", "23 18", args(&i, &j), args(23, 18), "too few operands"},
+	{"%d %d", "23 18 27", args(&i, &j, &k), args(23, 18), "too many operands"},
+	{"%c", "\u0100", args(&int8Val), nil, "overflow"},
+	{"X%d", "10X", args(&intVal), nil, "input does not match format"},
+
+	// Bad UTF-8: should see every byte.
+	{"%c%c%c", "\xc2X\xc2", args(&i, &j, &k), args(utf8.RuneError, 'X', utf8.RuneError), ""},
+}
+
+func testScan(name string, t *testing.T, scan func(r io.Reader, a ...interface{}) (int, os.Error)) {
+	for _, test := range scanTests {
+		var r io.Reader
+		if name == "StringReader" {
+			r = strings.NewReader(test.text)
+		} else {
+			r = newReader(test.text)
+		}
+		n, err := scan(r, test.in)
+		if err != nil {
+			t.Errorf("%s got error scanning %q: %s", name, test.text, err)
+			continue
+		}
+		if n != 1 {
+			t.Errorf("%s count error on entry %q: got %d", name, test.text, n)
+			continue
+		}
+		// The incoming value may be a pointer
+		v := reflect.NewValue(test.in)
+		if p, ok := v.(*reflect.PtrValue); ok {
+			v = p.Elem()
+		}
+		val := v.Interface()
+		if !reflect.DeepEqual(val, test.out) {
+			t.Errorf("%s scanning %q: expected %v got %v, type %T", name, test.text, test.out, val, val)
+		}
+	}
+}
+
+func TestScan(t *testing.T) {
+	testScan("StringReader", t, Fscan)
+}
+
+func TestMyReaderScan(t *testing.T) {
+	testScan("myStringReader", t, Fscan)
+}
+
+func TestScanln(t *testing.T) {
+	testScan("StringReader", t, Fscanln)
+}
+
+func TestMyReaderScanln(t *testing.T) {
+	testScan("myStringReader", t, Fscanln)
+}
+
+func TestScanf(t *testing.T) {
+	for _, test := range scanfTests {
+		n, err := Sscanf(test.text, test.format, test.in)
+		if err != nil {
+			t.Errorf("got error scanning (%q, %q): %s", test.format, test.text, err)
+			continue
+		}
+		if n != 1 {
+			t.Errorf("count error on entry (%q, %q): got %d", test.format, test.text, n)
+			continue
+		}
+		// The incoming value may be a pointer
+		v := reflect.NewValue(test.in)
+		if p, ok := v.(*reflect.PtrValue); ok {
+			v = p.Elem()
+		}
+		val := v.Interface()
+		if !reflect.DeepEqual(val, test.out) {
+			t.Errorf("scanning (%q, %q): expected %v got %v, type %T", test.format, test.text, test.out, val, val)
+		}
+	}
+}
+
+func TestScanOverflow(t *testing.T) {
+	// different machines and different types report errors with different strings.
+	re := regexp.MustCompile("overflow|too large|out of range|not representable")
+	for _, test := range overflowTests {
+		_, err := Sscan(test.text, test.in)
+		if err == nil {
+			t.Errorf("expected overflow scanning %q", test.text)
+			continue
+		}
+		if !re.MatchString(err.String()) {
+			t.Errorf("expected overflow error scanning %q: %s", test.text, err)
+		}
+	}
+}
+
+// TODO: there's no conversion from []T to ...T, but we can fake it.  These
+// functions do the faking.  We index the table by the length of the param list.
+var fscanf = []func(io.Reader, string, []interface{}) (int, os.Error){
+	0: func(r io.Reader, f string, i []interface{}) (int, os.Error) { return Fscanf(r, f) },
+	1: func(r io.Reader, f string, i []interface{}) (int, os.Error) { return Fscanf(r, f, i[0]) },
+	2: func(r io.Reader, f string, i []interface{}) (int, os.Error) { return Fscanf(r, f, i[0], i[1]) },
+	3: func(r io.Reader, f string, i []interface{}) (int, os.Error) { return Fscanf(r, f, i[0], i[1], i[2]) },
+}
+
+func testScanfMulti(name string, t *testing.T) {
+	sliceType := reflect.Typeof(make([]interface{}, 1)).(*reflect.SliceType)
+	for _, test := range multiTests {
+		var r io.Reader
+		if name == "StringReader" {
+			r = strings.NewReader(test.text)
+		} else {
+			r = newReader(test.text)
+		}
+		n, err := fscanf[len(test.in)](r, test.format, test.in)
+		if err != nil {
+			if test.err == "" {
+				t.Errorf("got error scanning (%q, %q): %q", test.format, test.text, err)
+			} else if strings.Index(err.String(), test.err) < 0 {
+				t.Errorf("got wrong error scanning (%q, %q): %q; expected %q", test.format, test.text, err, test.err)
+			}
+			continue
+		}
+		if test.err != "" {
+			t.Errorf("expected error %q error scanning (%q, %q)", test.err, test.format, test.text)
+		}
+		if n != len(test.out) {
+			t.Errorf("count error on entry (%q, %q): expected %d got %d", test.format, test.text, len(test.out), n)
+			continue
+		}
+		// Convert the slice of pointers into a slice of values
+		resultVal := reflect.MakeSlice(sliceType, n, n)
+		for i := 0; i < n; i++ {
+			v := reflect.NewValue(test.in[i]).(*reflect.PtrValue).Elem()
+			resultVal.Elem(i).(*reflect.InterfaceValue).Set(v)
+		}
+		result := resultVal.Interface()
+		if !reflect.DeepEqual(result, test.out) {
+			t.Errorf("scanning (%q, %q): expected %v got %v", test.format, test.text, test.out, result)
+		}
+	}
+}
+
+func TestScanfMulti(t *testing.T) {
+	testScanfMulti("StringReader", t)
+}
+
+func TestMyReaderScanfMulti(t *testing.T) {
+	testScanfMulti("myStringReader", t)
+}
+
+func TestScanMultiple(t *testing.T) {
+	var a int
+	var s string
+	n, err := Sscan("123abc", &a, &s)
+	if n != 2 {
+		t.Errorf("Sscan count error: expected 2: got %d", n)
+	}
+	if err != nil {
+		t.Errorf("Sscan expected no error; got %s", err)
+	}
+	if a != 123 || s != "abc" {
+		t.Errorf("Sscan wrong values: got (%d %q) expected (123 \"abc\")", a, s)
+	}
+	n, err = Sscan("asdf", &s, &a)
+	if n != 1 {
+		t.Errorf("Sscan count error: expected 1: got %d", n)
+	}
+	if err == nil {
+		t.Errorf("Sscan expected error; got none", err)
+	}
+	if s != "asdf" {
+		t.Errorf("Sscan wrong values: got %q expected \"asdf\"", s)
+	}
+}
+
+// Empty strings are not valid input when scanning a string.
+func TestScanEmpty(t *testing.T) {
+	var s1, s2 string
+	n, err := Sscan("abc", &s1, &s2)
+	if n != 1 {
+		t.Errorf("Sscan count error: expected 1: got %d", n)
+	}
+	if err == nil {
+		t.Errorf("Sscan <one item> expected error; got none")
+	}
+	if s1 != "abc" {
+		t.Errorf("Sscan wrong values: got %q expected \"abc\"", s1)
+	}
+	n, err = Sscan("", &s1, &s2)
+	if n != 0 {
+		t.Errorf("Sscan count error: expected 0: got %d", n)
+	}
+	if err == nil {
+		t.Errorf("Sscan <empty> expected error; got none")
+	}
+	// Quoted empty string is OK.
+	n, err = Sscanf(`""`, "%q", &s1)
+	if n != 1 {
+		t.Errorf("Sscanf count error: expected 1: got %d", n)
+	}
+	if err != nil {
+		t.Errorf("Sscanf <empty> expected no error with quoted string; got %s", err)
+	}
+}
+
+func TestScanNotPointer(t *testing.T) {
+	r := strings.NewReader("1")
+	var a int
+	_, err := Fscan(r, a)
+	if err == nil {
+		t.Error("expected error scanning non-pointer")
+	} else if strings.Index(err.String(), "pointer") < 0 {
+		t.Errorf("expected pointer error scanning non-pointer, got: %s", err)
+	}
+}
+
+func TestScanlnNoNewline(t *testing.T) {
+	var a int
+	_, err := Sscanln("1 x\n", &a)
+	if err == nil {
+		t.Error("expected error scanning string missing newline")
+	} else if strings.Index(err.String(), "newline") < 0 {
+		t.Errorf("expected newline error scanning string missing newline, got: %s", err)
+	}
+}
+
+func TestScanlnWithMiddleNewline(t *testing.T) {
+	r := strings.NewReader("123\n456\n")
+	var a, b int
+	_, err := Fscanln(r, &a, &b)
+	if err == nil {
+		t.Error("expected error scanning string with extra newline")
+	} else if strings.Index(err.String(), "newline") < 0 {
+		t.Errorf("expected newline error scanning string with extra newline, got: %s", err)
+	}
+}
+
+// Special Reader that counts reads at end of file.
+type eofCounter struct {
+	reader   *strings.Reader
+	eofCount int
+}
+
+func (ec *eofCounter) Read(b []byte) (n int, err os.Error) {
+	n, err = ec.reader.Read(b)
+	if n == 0 {
+		ec.eofCount++
+	}
+	return
+}
+
+// Verify that when we scan, we see at most EOF once per call to a Scan function,
+// and then only when it's really an EOF
+func TestEOF(t *testing.T) {
+	ec := &eofCounter{strings.NewReader("123\n"), 0}
+	var a int
+	n, err := Fscanln(ec, &a)
+	if err != nil {
+		t.Error("unexpected error", err)
+	}
+	if n != 1 {
+		t.Error("expected to scan one item, got", n)
+	}
+	if ec.eofCount != 0 {
+		t.Error("expected zero EOFs", ec.eofCount)
+		ec.eofCount = 0 // reset for next test
+	}
+	n, err = Fscanln(ec, &a)
+	if err == nil {
+		t.Error("expected error scanning empty string")
+	}
+	if n != 0 {
+		t.Error("expected to scan zero items, got", n)
+	}
+	if ec.eofCount != 1 {
+		t.Error("expected one EOF, got", ec.eofCount)
+	}
+}
+
+// Verify that, at least when using bufio, successive calls to Fscan do not lose runes.
+func TestUnreadRuneWithBufio(t *testing.T) {
+	r := bufio.NewReader(strings.NewReader("123αb"))
+	var i int
+	var a string
+	n, err := Fscanf(r, "%d", &i)
+	if n != 1 || err != nil {
+		t.Errorf("reading int expected one item, no errors; got %d %q", n, err)
+	}
+	if i != 123 {
+		t.Errorf("expected 123; got %d", i)
+	}
+	n, err = Fscanf(r, "%s", &a)
+	if n != 1 || err != nil {
+		t.Errorf("reading string expected one item, no errors; got %d %q", n, err)
+	}
+	if a != "αb" {
+		t.Errorf("expected αb; got %q", a)
+	}
+}