bug284: test cases for new conversion rules

R=rsc, r, iant
CC=golang-dev
https://golang.org/cl/1465041

test/bugs/bug284.go

+// errchk $G $D/$F.go
+
+// Copyright 2010 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.
+
+// Test cases for revised conversion rules.
+
+package main
+
+func main() {
+	type NewInt int
+	i0 := 0
+	var i1 int = 1
+	var i2 NewInt = 1
+	i0 = i0
+	i0 = i1
+	i0 = int(i2)
+	i1 = i0
+	i1 = i1
+	i1 = int(i2)
+	i2 = NewInt(i0)
+	i2 = NewInt(i1)
+	i2 = i2
+
+	type A1 [3]int
+	type A2 [3]NewInt
+	var a0 [3]int
+	var a1 A1
+	var a2 A2
+	a0 = a0
+	a0 = a1
+	a0 = [3]int(a2) // ERROR "cannot"
+	a1 = a0
+	a1 = a1
+	a1 = A1(a2) // ERROR "cannot"
+	a2 = A2(a0) // ERROR "cannot"
+	a2 = A2(a1) // ERROR "cannot"
+	a2 = a2
+
+	type S1 struct {
+		x int
+	}
+	type S2 struct {
+		x NewInt
+	}
+	var s0 struct {
+		x int
+	}
+	var s1 S1
+	var s2 S2
+	s0 = s0
+	s0 = s1
+	s0 = struct {
+		x int
+	}(s2) // ERROR "cannot"
+	s1 = s0
+	s1 = s1
+	s1 = S1(s2) // ERROR "cannot"
+	s2 = S2(s0) // ERROR "cannot"
+	s2 = S2(s1) // ERROR "cannot"
+	s2 = s2
+
+	type P1 *int
+	type P2 *NewInt
+	var p0 *int
+	var p1 P1
+	var p2 P2
+	p0 = p0
+	p0 = p1
+	p0 = (*int)(p2) // ERROR "cannot"
+	p1 = p0
+	p1 = p1
+	p1 = P1(p2) // ERROR "cannot"
+	p2 = P2(p0) // ERROR "cannot"
+	p2 = P2(p1) // ERROR "cannot"
+	p2 = p2
+
+	type Q1 *struct {
+		x int
+	}
+	type Q2 *S1
+	var q0 *struct {
+		x int
+	}
+	var q1 Q1
+	var q2 Q2
+	q0 = q0
+	q0 = q1
+	q0 = (*struct {
+		x int
+	})(q2) // legal because of special conversion exception for pointers
+	q1 = q0
+	q1 = q1
+	q1 = Q1(q2)    // ERROR "cannot"
+	q2 = (*S1)(q0) // legal because of special conversion exception for pointers
+	q2 = Q2(q1)    // ERROR "cannot"
+	q2 = q2
+
+	type F1 func(x NewInt) int
+	type F2 func(x int) NewInt
+	var f0 func(x NewInt) int
+	var f1 F1
+	var f2 F2
+	f0 = f0
+	f0 = f1
+	f0 = func(x NewInt) int(f2) // ERROR "cannot"
+	f1 = f0
+	f1 = f1
+	f1 = F1(f2) // ERROR "cannot"
+	f2 = F2(f0) // ERROR "cannot"
+	f2 = F2(f1) // ERROR "cannot"
+	f2 = f2
+
+	type X1 interface {
+		f() int
+	}
+	type X2 interface {
+		f() NewInt
+	}
+	var x0 interface {
+		f() int
+	}
+	var x1 X1
+	var x2 X2
+	x0 = x0
+	x0 = x1
+	x0 = interface {
+		f() int
+	}(x2) // ERROR "cannot"|"need type assertion"
+	x1 = x0
+	x1 = x1
+	x1 = X1(x2) // ERROR "cannot"|"need type assertion"
+	x2 = X2(x0) // ERROR "cannot"|"need type assertion"
+	x2 = X2(x1) // ERROR "cannot"|"need type assertion"
+	x2 = x2
+
+	type L1 []int
+	type L2 []NewInt
+	var l0 []int
+	var l1 L1
+	var l2 L2
+	l0 = l0
+	l0 = l1
+	l0 = []int(l2) // ERROR "cannot"
+	l1 = l0
+	l1 = l1
+	l1 = L1(l2) // ERROR "cannot"
+	l2 = L2(l0) // ERROR "cannot"
+	l2 = L2(l1) // ERROR "cannot"
+	l2 = l2
+
+	type M1 map[string]int
+	type M2 map[string]NewInt
+	var m0 []int
+	var m1 L1
+	var m2 L2
+	m0 = m0
+	m0 = m1
+	m0 = []int(m2) // ERROR "cannot"
+	m1 = m0
+	m1 = m1
+	m1 = L1(m2) // ERROR "cannot"
+	m2 = L2(m0) // ERROR "cannot"
+	m2 = L2(m1) // ERROR "cannot"
+	m2 = m2
+
+	type C1 chan int
+	type C2 chan NewInt
+	var c0 chan int
+	var c1 C1
+	var c2 C2
+	c0 = c0
+	c0 = c1
+	c0 = chan int(c2) // ERROR "cannot"
+	c1 = c0
+	c1 = c1
+	c1 = C1(c2) // ERROR "cannot"
+	c2 = C2(c0) // ERROR "cannot"
+	c2 = C2(c1) // ERROR "cannot"
+	c2 = c2
+}

test/golden.out

@@ -180,3 +180,39 @@ BUG: bug260 failed
 
 =========== bugs/bug274.go
 BUG: errchk: command succeeded unexpectedly
+
+=========== bugs/bug284.go
+BUG: errchk: bugs/bug284.go:33: missing expected error: 'cannot'
+errchk: bugs/bug284.go:36: missing expected error: 'cannot'
+errchk: bugs/bug284.go:37: missing expected error: 'cannot'
+errchk: bugs/bug284.go:38: missing expected error: 'cannot'
+errchk: bugs/bug284.go:56: missing expected error: 'cannot'
+errchk: bugs/bug284.go:59: missing expected error: 'cannot'
+errchk: bugs/bug284.go:60: missing expected error: 'cannot'
+errchk: bugs/bug284.go:61: missing expected error: 'cannot'
+errchk: bugs/bug284.go:71: missing expected error: 'cannot'
+errchk: bugs/bug284.go:74: missing expected error: 'cannot'
+errchk: bugs/bug284.go:75: missing expected error: 'cannot'
+errchk: bugs/bug284.go:76: missing expected error: 'cannot'
+errchk: bugs/bug284.go:95: missing expected error: 'cannot'
+errchk: bugs/bug284.go:97: missing expected error: 'cannot'
+errchk: bugs/bug284.go:107: missing expected error: 'cannot'
+errchk: bugs/bug284.go:110: missing expected error: 'cannot'
+errchk: bugs/bug284.go:111: missing expected error: 'cannot'
+errchk: bugs/bug284.go:112: missing expected error: 'cannot'
+errchk: bugs/bug284.go:130: error message does not match 'cannot'
+errchk: bugs/bug284.go:133: error message does not match 'cannot'
+errchk: bugs/bug284.go:134: error message does not match 'cannot'
+errchk: bugs/bug284.go:135: error message does not match 'cannot'
+errchk: bugs/bug284.go:145: missing expected error: 'cannot'
+errchk: bugs/bug284.go:148: missing expected error: 'cannot'
+errchk: bugs/bug284.go:149: missing expected error: 'cannot'
+errchk: bugs/bug284.go:150: missing expected error: 'cannot'
+errchk: bugs/bug284.go:160: missing expected error: 'cannot'
+errchk: bugs/bug284.go:163: missing expected error: 'cannot'
+errchk: bugs/bug284.go:164: missing expected error: 'cannot'
+errchk: bugs/bug284.go:165: missing expected error: 'cannot'
+errchk: bugs/bug284.go:175: missing expected error: 'cannot'
+errchk: bugs/bug284.go:178: missing expected error: 'cannot'
+errchk: bugs/bug284.go:179: missing expected error: 'cannot'
+errchk: bugs/bug284.go:180: missing expected error: 'cannot'