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// Copyright 2012 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. // statements package stmt0 func assignments0() (int, int) { var a, b, c int var ch chan int f0 := func() {} f1 := func() int { return 1 } f2 := func() (int, int) { return 1, 2 } f3 := func() (int, int, int) { return 1, 2, 3 } a, b, c = 1, 2, 3 a, b, c = 1 /* ERROR "assignment mismatch: 3 variables but 2 values" */ , 2 a, b, c = 1 /* ERROR "assignment mismatch: 3 variables but 4 values" */ , 2, 3, 4 _, _, _ = a, b, c a = f0 /* ERROR "used as value" */ () a = f1() a = f2 /* ERROR "assignment mismatch: 1 variable but f2 returns 2 values" */ () a, b = f2() a, b, c = f2 /* ERROR "assignment mismatch: 3 variables but f2 returns 2 values" */ () a, b, c = f3() a, b = f3 /* ERROR "assignment mismatch: 2 variables but f3 returns 3 values" */ () a, b, c = <- /* ERROR "assignment mismatch: 3 variables but 1 value" */ ch return /* ERROR "not enough return values\n\thave ()\n\twant (int, int)" */ return 1 /* ERROR "not enough return values\n\thave (number)\n\twant (int, int)" */ return 1, 2 return 1, 2, 3 /* ERROR "too many return values\n\thave (number, number, number)\n\twant (int, int)" */ } func assignments1() { b, i, f, c, s := false, 1, 1.0, 1i, "foo" b = i /* ERRORx `cannot use .* in assignment` */ i = f /* ERRORx `cannot use .* in assignment` */ f = c /* ERRORx `cannot use .* in assignment` */ c = s /* ERRORx `cannot use .* in assignment` */ s = b /* ERRORx `cannot use .* in assignment` */ v0, v1, v2 := 1 /* ERROR "assignment mismatch" */ , 2, 3, 4 _, _, _ = v0, v1, v2 b = true i += 1 i /* ERROR "mismatched types int and untyped string" */+= "foo" f -= 1 f /= 0 f = float32(0)/0 /* ERROR "division by zero" */ f /* ERROR "mismatched types float64 and untyped string" */-= "foo" c *= 1 c /= 0 s += "bar" s /* ERROR "mismatched types string and untyped int" */+= 1 var u64 uint64 u64 += 1<<u64 undefined /* ERROR "undefined" */ = 991 // test cases for issue 5800 var ( _ int = nil /* ERROR "cannot use nil as int value in variable declaration" */ _ [10]int = nil /* ERROR "cannot use nil as [10]int value in variable declaration" */ _ []byte = nil _ struct{} = nil /* ERROR "cannot use nil as struct{} value in variable declaration" */ _ func() = nil _ map[int]string = nil _ chan int = nil ) // test cases for issue 5500 _ = func() (int, bool) { var m map[int]int return m /* ERROR "not enough return values" */ [0] } g := func(int, bool){} var m map[int]int g(m[0]) /* ERROR "not enough arguments" */ // assignments to _ _ = nil /* ERROR "use of untyped nil" */ _ = 1 << /* ERROR "constant shift overflow" */ 1000 (_) = 0 } func assignments2() { type mybool bool var m map[string][]bool var s []bool var b bool var d mybool _ = s _ = b _ = d // assignments to map index expressions are ok s, b = m["foo"] _, d = m["bar"] m["foo"] = nil m["foo"] = nil /* ERROR "assignment mismatch: 1 variable but 2 values" */ , false _ = append(m["foo"]) _ = append(m["foo"], true) var c chan int _, b = <-c _, d = <-c <- /* ERROR "cannot assign" */ c = 0 <-c = 0 /* ERROR "assignment mismatch: 1 variable but 2 values" */ , false var x interface{} _, b = x.(int) x /* ERROR "cannot assign" */ .(int) = 0 x.(int) = 0 /* ERROR "assignment mismatch: 1 variable but 2 values" */ , false assignments2 /* ERROR "used as value" */ () = nil int /* ERROR "not an expression" */ = 0 } func issue6487() { type S struct{x int} _ = &S /* ERROR "cannot take address" */ {}.x _ = &( /* ERROR "cannot take address" */ S{}.x) _ = (&S{}).x S /* ERROR "cannot assign" */ {}.x = 0 (&S{}).x = 0 type M map[string]S var m M m /* ERROR "cannot assign to struct field" */ ["foo"].x = 0 _ = &( /* ERROR "cannot take address" */ m["foo"].x) _ = &m /* ERROR "cannot take address" */ ["foo"].x } func issue6766a() { a, a /* ERROR "a repeated on left side of :=" */ := 1, 2 _ = a a, b, b /* ERROR "b repeated on left side of :=" */ := 1, 2, 3 _ = b c, c /* ERROR "c repeated on left side of :=" */, b := 1, 2, 3 _ = c a, b := /* ERROR "no new variables" */ 1, 2 } func shortVarDecls1() { const c = 0 type d int a, b, c /* ERROR "cannot assign" */ , d /* ERROR "cannot assign" */ := 1, "zwei", 3.0, 4 var _ int = a // a is of type int var _ string = b // b is of type string } func incdecs() { const c = 3.14 c /* ERROR "cannot assign" */ ++ s := "foo" s /* ERROR "invalid operation" */ -- 3.14 /* ERROR "cannot assign" */ ++ var ( x int y float32 z complex128 ) x++ y-- z++ } func sends() { var ch chan int var rch <-chan int var x int x <- /* ERROR "cannot send" */ x rch <- /* ERROR "cannot send" */ x ch <- "foo" /* ERRORx `cannot use .* in send` */ ch <- x } func selects() { select {} var ( ch chan int sc chan <- bool ) select { case <-ch: case (<-ch): case t := <-ch: _ = t case t := (<-ch): _ = t case t, ok := <-ch: _, _ = t, ok case t, ok := (<-ch): _, _ = t, ok case <-sc /* ERROR "cannot receive from send-only channel" */ : } select { default: default /* ERROR "multiple defaults" */ : } select { case a, b := <-ch: _, b = a, b case x /* ERROR "send or receive" */ : case a /* ERROR "send or receive" */ := ch: } // test for issue 9570: ch2 in second case falsely resolved to // ch2 declared in body of first case ch1 := make(chan int) ch2 := make(chan int) select { case <-ch1: var ch2 /* ERROR "ch2 declared and not used" */ chan bool case i := <-ch2: print(i + 1) } } func gos() { go 1; /* ERROR "must be function call" */ go int /* ERROR "go requires function call, not conversion" */ (0) go ( /* ERROR "expression in go must not be parenthesized" */ gos()) go gos() var c chan int go close(c) go len /* ERROR "go discards result" */ (c) } func defers() { defer 1; /* ERROR "must be function call" */ defer int /* ERROR "defer requires function call, not conversion" */ (0) defer ( /* ERROR "expression in defer must not be parenthesized" */ defers()) defer defers() var c chan int defer close(c) defer len /* ERROR "defer discards result" */ (c) } func breaks() { var x, y int break /* ERROR "break" */ { break /* ERROR "break" */ } if x < y { break /* ERROR "break" */ } switch x { case 0: break case 1: if x == y { break } default: break break } var z interface{} switch z.(type) { case int: break } for { break } var a []int for _ = range a { break } for { if x == y { break } } var ch chan int select { case <-ch: break } select { case <-ch: if x == y { break } default: break } } func continues() { var x, y int continue /* ERROR "continue" */ { continue /* ERROR "continue" */ } if x < y { continue /* ERROR "continue" */ } switch x { case 0: continue /* ERROR "continue" */ } var z interface{} switch z.(type) { case int: continue /* ERROR "continue" */ } var ch chan int select { case <-ch: continue /* ERROR "continue" */ } for i := 0; i < 10; i++ { continue if x < y { continue break } switch x { case y: continue default: break } select { case <-ch: continue } } var a []int for _ = range a { continue if x < y { continue break } switch x { case y: continue default: break } select { case <-ch: continue } } } func returns0() { return return 0 /* ERROR "too many return values" */ } func returns1(x float64) (int, *float64) { return 0, &x return /* ERROR "not enough return values" */ return "foo" /* ERRORx `cannot .* in return statement` */, x /* ERRORx `cannot use .* in return statement` */ return 0, &x, 1 /* ERROR "too many return values" */ } func returns2() (a, b int) { return return 1, "foo" /* ERRORx `cannot use .* in return statement` */ return 1, 2, 3 /* ERROR "too many return values" */ { type a int return 1, 2 return /* ERROR "a not in scope at return" */ } } func returns3() (_ int) { return { var _ int // blank (_) identifiers never shadow since they are in no scope return } } func switches0() { var x int switch x { } switch x { default: default /* ERROR "multiple defaults" */ : } switch { case 1 /* ERROR "cannot convert" */ : } true := "false" _ = true // A tagless switch is equivalent to the bool // constant true, not the identifier 'true'. switch { case "false" /* ERROR "cannot convert" */: } switch int32(x) { case 1, 2: case x /* ERROR "invalid case x in switch on int32(x) (mismatched types int and int32)" */ : } switch x { case 1 /* ERROR "overflows" */ << 100: } switch x { case 1: case 1 /* ERROR "duplicate case" */ : case ( /* ERROR "duplicate case" */ 1): case 2, 3, 4: case 5, 1 /* ERROR "duplicate case" */ : } switch uint64(x) { case 1<<64 - 1: case 1 /* ERROR "duplicate case" */ <<64 - 1: case 2, 3, 4: case 5, 1 /* ERROR "duplicate case" */ <<64 - 1: } var y32 float32 switch y32 { case 1.1: case 11/10: // integer division! case 11. /* ERROR "duplicate case" */ /10: case 2, 3.0, 4.1: case 5.2, 1.10 /* ERROR "duplicate case" */ : } var y64 float64 switch y64 { case 1.1: case 11/10: // integer division! case 11. /* ERROR "duplicate case" */ /10: case 2, 3.0, 4.1: case 5.2, 1.10 /* ERROR "duplicate case" */ : } var s string switch s { case "foo": case "foo" /* ERROR "duplicate case" */ : case "f" /* ERROR "duplicate case" */ + "oo": case "abc", "def", "ghi": case "jkl", "foo" /* ERROR "duplicate case" */ : } type T int type F float64 type S string type B bool var i interface{} switch i { case nil: case nil: // no duplicate detection case (*int)(nil): case (*int)(nil): // do duplicate detection case 1: case byte(1): case int /* ERROR "duplicate case" */ (1): case T(1): case 1.0: case F(1.0): case F /* ERROR "duplicate case" */ (1.0): case "hello": case S("hello"): case S /* ERROR "duplicate case" */ ("hello"): case 1==1, B(false): case false, B(2==2): } // switch on array var a [3]int switch a { case [3]int{1, 2, 3}: case [3]int{1, 2, 3}: // no duplicate detection case [ /* ERROR "mismatched types" */ 4]int{4, 5, 6}: } // switch on channel var c1, c2 chan int switch c1 { case nil: case c1: case c2: case c1, c2: // no duplicate detection } } func switches1() { fallthrough /* ERROR "fallthrough statement out of place" */ var x int switch x { case 0: fallthrough /* ERROR "fallthrough statement out of place" */ break case 1: fallthrough case 2: fallthrough; ; ; // trailing empty statements are ok case 3: default: fallthrough; ; case 4: fallthrough /* ERROR "cannot fallthrough final case in switch" */ } var y interface{} switch y.(type) { case int: fallthrough /* ERROR "cannot fallthrough in type switch" */ ; ; ; default: } switch x { case 0: if x == 0 { fallthrough /* ERROR "fallthrough statement out of place" */ } } switch x { case 0: goto L1 L1: fallthrough; ; case 1: goto L2 goto L3 goto L4 L2: L3: L4: fallthrough default: } switch x { case 0: goto L5 L5: fallthrough default: goto L6 goto L7 goto L8 L6: L7: L8: fallthrough /* ERROR "cannot fallthrough final case in switch" */ } switch x { case 0: fallthrough; ; case 1: { fallthrough /* ERROR "fallthrough statement out of place" */ } case 2: fallthrough case 3: fallthrough /* ERROR "fallthrough statement out of place" */ { /* empty block is not an empty statement */ }; ; default: fallthrough /* ERROR "cannot fallthrough final case in switch" */ } switch x { case 0: { fallthrough /* ERROR "fallthrough statement out of place" */ } } } func switches2() { // untyped nil is not permitted as switch expression switch nil /* ERROR "use of untyped nil" */ { case 1, 2, "foo": // don't report additional errors here } // untyped constants are converted to default types switch 1<<63-1 { } switch 1 /* ERRORx `cannot use .* as int value.*\(overflows\)` */ << 63 { } var x int switch 1.0 { case 1.0, 2.0, x /* ERROR "mismatched types int and float64" */ : } switch x { case 1.0: } // untyped bools become of type bool type B bool var b B = true switch x == x { case b /* ERROR "mismatched types B and bool" */ : } switch { case b /* ERROR "mismatched types B and bool" */ : } } func issue11667() { switch 9223372036854775808 /* ERRORx `cannot use .* as int value.*\(overflows\)` */ { } switch 9223372036854775808 /* ERRORx `cannot use .* as int value.*\(overflows\)` */ { case 9223372036854775808: } var x int switch x { case 9223372036854775808 /* ERROR "overflows int" */ : } var y float64 switch y { case 9223372036854775808: } } func issue11687() { f := func() (_, _ int) { return } switch f /* ERROR "multiple-value f" */ () { } var x int switch f /* ERROR "multiple-value f" */ () { case x: } switch x { case f /* ERROR "multiple-value f" */ (): } } type I interface { m() } type I2 interface { m(int) } type T struct{} type T1 struct{} type T2 struct{} func (T) m() {} func (T2) m(int) {} func typeswitches() { var i int var x interface{} switch x.(type) {} switch (x /* ERROR "outside type switch" */ .(type)) {} switch x.(type) { default: default /* ERROR "multiple defaults" */ : } switch x /* ERROR "declared and not used" */ := x.(type) {} switch _ /* ERROR "no new variable on left side of :=" */ := x.(type) {} switch x := x.(type) { case int: var y int = x _ = y } switch x /* ERROR "x declared and not used" */ := i /* ERROR "not an interface" */ .(type) {} switch t := x.(type) { case nil: var v bool = t /* ERRORx `cannot use .* in variable declaration` */ _ = v case int: var v int = t _ = v case float32, complex64: var v float32 = t /* ERRORx `cannot use .* in variable declaration` */ _ = v default: var v float32 = t /* ERRORx `cannot use .* in variable declaration` */ _ = v } var t I switch t.(type) { case T: case T1 /* ERROR "missing method m" */ : case T2 /* ERROR "wrong type for method m" */ : case I2 /* STRICT "wrong type for method m" */ : // only an error in strict mode (issue 8561) } { x := 1 v := 2 switch v /* ERROR "v (variable of type int) is not an interface" */ .(type) { case int: println(x) println(x / 0 /* ERROR "invalid operation: division by zero" */) case 1 /* ERROR "1 is not a type" */: } } } // Test that each case clause uses the correct type of the variable // declared by the type switch (issue 5504). func typeswitch0() { switch y := interface{}(nil).(type) { case int: func() int { return y + 0 }() case float32: func() float32 { return y }() } } // Test correct scope setup. // (no redeclaration errors expected in the type switch) func typeswitch1() { var t I switch t := t; t := t.(type) { case nil: var _ I = t case T: var _ T = t default: var _ I = t } } // Test correct typeswitch against interface types. type A interface { a() } type B interface { b() } type C interface { a(int) } func typeswitch2() { switch A(nil).(type) { case A: case B: case C /* STRICT "cannot have dynamic type" */: // only an error in strict mode (issue 8561) } } func typeswitch3(x interface{}) { switch x.(type) { case int: case float64: case int /* ERROR "duplicate case" */ : } switch x.(type) { case nil: case int: case nil /* ERROR "duplicate case" */ , nil /* ERROR "duplicate case" */ : } type F func(int) switch x.(type) { case nil: case int, func(int): case float32, func /* ERROR "duplicate case" */ (x int): case F: } } func fors1() { for {} var i string _ = i for i := 0; i < 10; i++ {} for i := 0; i < 10; j /* ERROR "cannot declare" */ := 0 {} } func rangeloops1() { var ( x int a [10]float32 b []string p *[10]complex128 pp **[10]complex128 s string m map[int]bool c chan int sc chan<- int rc <-chan int ) for range x /* ERROR "cannot range over" */ {} for _ = range x /* ERROR "cannot range over" */ {} for i := range x /* ERROR "cannot range over" */ {} for range a {} for i := range a { var ii int ii = i _ = ii } for i, x := range a { var ii int ii = i _ = ii var xx float64 xx = x /* ERRORx `cannot use .* in assignment` */ _ = xx } var ii int var xx float32 for ii, xx = range a {} _, _ = ii, xx for range b {} for i := range b { var ii int ii = i _ = ii } for i, x := range b { var ii int ii = i _ = ii var xx string xx = x _ = xx } for range s {} for i := range s { var ii int ii = i _ = ii } for i, x := range s { var ii int ii = i _ = ii var xx rune xx = x _ = xx } for range p {} for _, x := range p { var xx complex128 xx = x _ = xx } for range pp /* ERROR "cannot range over" */ {} for _, x := range pp /* ERROR "cannot range over" */ {} for range m {} for k := range m { var kk int32 kk = k /* ERRORx `cannot use .* in assignment` */ _ = kk } for k, v := range m { var kk int kk = k _ = kk if v {} } for range c {} for _, _ /* ERROR "only one iteration variable" */ = range c {} for e := range c { var ee int ee = e _ = ee } for _ = range sc /* ERROR "cannot range over" */ {} for _ = range rc {} // constant strings const cs = "foo" for range cs {} for range "" {} for i, x := range cs { _, _ = i, x } for i, x := range "" { var ii int ii = i _ = ii var xx rune xx = x _ = xx } } func rangeloops2() { type I int type R rune var a [10]int var i I _ = i for i /* ERRORx `cannot use .* in assignment` */ = range a {} for i /* ERRORx `cannot use .* in assignment` */ = range &a {} for i /* ERRORx `cannot use .* in assignment` */ = range a[:] {} var s string var r R _ = r for i /* ERRORx `cannot use .* in assignment` */ = range s {} for i /* ERRORx `cannot use .* in assignment` */ = range "foo" {} for _, r /* ERRORx `cannot use .* in assignment` */ = range s {} for _, r /* ERRORx `cannot use .* in assignment` */ = range "foo" {} } func issue6766b() { for _ := /* ERROR "no new variables" */ range "" {} for a, a /* ERROR "redeclared" */ := range "" { _ = a } var a int _ = a for a, a /* ERROR "redeclared" */ := range []int{1, 2, 3} { _ = a } } // Test that despite errors in the range clause, // the loop body is still type-checked (and thus // errors reported). func issue10148() { for y /* ERROR "declared and not used" */ := range "" { _ = "" /* ERROR "mismatched types untyped string and untyped int" */ + 1 } for range 1 /* ERROR "cannot range over 1" */ { _ = "" /* ERROR "mismatched types untyped string and untyped int" */ + 1 } for y := range 1 /* ERROR "cannot range over 1" */ { _ = "" /* ERROR "mismatched types untyped string and untyped int" */ + 1 } } func labels0() { goto L0 goto L1 L0: L1: L1 /* ERROR "already declared" */ : if true { goto L2 L2: L0 /* ERROR "already declared" */ : } _ = func() { goto L0 goto L1 goto L2 L0: L1: L2: } } func expression_statements(ch chan int) { expression_statements(ch) <-ch println() 0 /* ERROR "not used" */ 1 /* ERROR "not used" */ +2 cap /* ERROR "not used" */ (ch) println /* ERROR "must be called" */ }