[dev.typeparams] merge: merge branch 'dev.regabi' into 'dev.typeparams'

The following files had merge conflicts and were merged manually:

	src/cmd/compile/fmtmap_test.go
	src/cmd/compile/internal/gc/noder.go
	src/go/parser/error_test.go
	test/assign.go
	test/chan/perm.go
	test/fixedbugs/issue22822.go
	test/fixedbugs/issue4458.go
	test/init.go
	test/interface/explicit.go
	test/map1.go
	test/method2.go

The following files had manual changes to make tests pass:

	test/run.go
	test/used.go
	src/cmd/compile/internal/types2/stdlib_test.go

Change-Id: Ia495aaaa80ce321ee4ec2a9105780fbe913dbd4c

38 files changed, 365 insertions, 76 deletions

diff --git a/test/assign.go b/test/assign.go
index 549f42eb80..bdec58b710 100644
--- a/test/assign.go
+++ b/test/assign.go
@@ -42,7 +42,7 @@ func main() {
 		_ = x
 	}
 	{
-		x := sync.Mutex{key: 0} // ERROR "(unknown|assignment).*Mutex|unknown field.* in struct literal"
+		x := sync.Mutex{key: 0} // ERROR "(unknown|assignment).*Mutex"
 		_ = x
 	}
 	{
@@ -56,13 +56,13 @@ func main() {
 	{
 		var x = 1
 		{
-			x, x := 2, 3 // ERROR "x repeated on left side of :=|x redeclared in this block"
+			x, x := 2, 3 // ERROR ".*x.* repeated on left side of :=|x redeclared in this block"
 			_ = x
 		}
 		_ = x
 	}
 	{
-		a, a := 1, 2 // ERROR "a repeated on left side of :=|a redeclared in this block"
+		a, a := 1, 2 // ERROR ".*a.* repeated on left side of :=|a redeclared in this block"
 		_ = a
 	}
 }
diff --git a/test/blank1.go b/test/blank1.go
index 3c981cd5eb..815a7e9b5a 100644
--- a/test/blank1.go
+++ b/test/blank1.go
@@ -13,7 +13,7 @@ var t struct {
 	_ int
 }
 
-func (x int) _() { // ERROR "cannot define new methods on non-local type"
+func (x int) _() { // ERROR "methods on non-local type"
 	println(x)
 }
 
diff --git a/test/chan/perm.go b/test/chan/perm.go
index 607a356a02..4c94ab7ffa 100644
--- a/test/chan/perm.go
+++ b/test/chan/perm.go
@@ -25,8 +25,8 @@ func main() {
 	cs = cr // ERROR "illegal types|incompatible|cannot"
 
 	var n int
-	<-n    // ERROR "receive from non-chan"
-	n <- 2 // ERROR "send to non-chan"
+	<-n    // ERROR "receive from non-chan|expected channel"
+	n <- 2 // ERROR "send to non-chan|must be channel"
 
 	c <- 0       // ok
 	<-c          // ok
@@ -66,5 +66,5 @@ func main() {
 	close(c)
 	close(cs)
 	close(cr) // ERROR "receive"
-	close(n)  // ERROR "invalid operation.*non-chan type|not a channel"
+	close(n)  // ERROR "invalid operation.*non-chan type|must be channel|not a channel"
 }
diff --git a/test/complit1.go b/test/complit1.go
index eb0f920fcb..7c2a4e2996 100644
--- a/test/complit1.go
+++ b/test/complit1.go
@@ -22,9 +22,9 @@ var (
 	_ = m[0][:]            // ERROR "slice of unaddressable value"
 	_ = f()[:]             // ERROR "slice of unaddressable value"
 
-	_ = 301[:]  // ERROR "cannot slice"
-	_ = 3.1[:]  // ERROR "cannot slice"
-	_ = true[:] // ERROR "cannot slice"
+	_ = 301[:]  // ERROR "cannot slice|attempt to slice object that is not"
+	_ = 3.1[:]  // ERROR "cannot slice|attempt to slice object that is not"
+	_ = true[:] // ERROR "cannot slice|attempt to slice object that is not"
 
 	// these are okay because they are slicing a pointer to an array
 	_ = (&[3]int{1, 2, 3})[:]
@@ -46,8 +46,8 @@ var (
 	_ = &T{0, 0, "", nil}               // ok
 	_ = &T{i: 0, f: 0, s: "", next: {}} // ERROR "missing type in composite literal|omit types within composite literal"
 	_ = &T{0, 0, "", {}}                // ERROR "missing type in composite literal|omit types within composite literal"
-	_ = TP{i: 0, f: 0, s: "", next: {}} // ERROR "invalid composite literal type TP"
-	_ = &Ti{}                           // ERROR "invalid composite literal type Ti"
+	_ = TP{i: 0, f: 0, s: "", next: {}} // ERROR "invalid composite literal type TP|omit types within composite literal"
+	_ = &Ti{}                           // ERROR "invalid composite literal type Ti|expected.*type for composite literal"
 )
 
 type M map[T]T
diff --git a/test/convlit.go b/test/convlit.go
index de760542da..1c66c89e88 100644
--- a/test/convlit.go
+++ b/test/convlit.go
@@ -21,9 +21,9 @@ var x6 = int(1e100)      // ERROR "overflow"
 var x7 = float32(1e1000) // ERROR "overflow"
 
 // unsafe.Pointer can only convert to/from uintptr
-var _ = string(unsafe.Pointer(uintptr(65)))  // ERROR "convert"
-var _ = float64(unsafe.Pointer(uintptr(65))) // ERROR "convert"
-var _ = int(unsafe.Pointer(uintptr(65)))     // ERROR "convert"
+var _ = string(unsafe.Pointer(uintptr(65)))  // ERROR "convert|conversion"
+var _ = float64(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion"
+var _ = int(unsafe.Pointer(uintptr(65)))     // ERROR "convert|conversion"
 
 // implicit conversions merit scrutiny
 var s string
diff --git a/test/ddd1.go b/test/ddd1.go
index 9857814648..01b9c0eadb 100644
--- a/test/ddd1.go
+++ b/test/ddd1.go
@@ -60,5 +60,5 @@ func bad(args ...int) {
 	_ = [...]byte("foo") // ERROR "[.][.][.]"
 	_ = [...][...]int{{1,2,3},{4,5,6}}	// ERROR "[.][.][.]"
 
-	Foo(x...) // ERROR "invalid use of [.][.][.] in call"
+	Foo(x...) // ERROR "invalid use of .*[.][.][.]"
 }
diff --git a/test/fixedbugs/bug176.go b/test/fixedbugs/bug176.go
index ea3a909747..7001dd081e 100644
--- a/test/fixedbugs/bug176.go
+++ b/test/fixedbugs/bug176.go
@@ -9,6 +9,6 @@ package main
 var x int
 
 var a = []int{ x: 1}	// ERROR "constant"
-var b = [...]int{x: 1}
+var b = [...]int{x: 1}	// GCCGO_ERROR "constant"
 var c = map[int]int{ x: 1}
 
diff --git a/test/fixedbugs/bug332.go b/test/fixedbugs/bug332.go
index d43c2ddcff..159c8b4e68 100644
--- a/test/fixedbugs/bug332.go
+++ b/test/fixedbugs/bug332.go
@@ -14,4 +14,4 @@ func main() {}
 
 // important: no newline on end of next line.
 // 6g used to print <epoch> instead of bug332.go:111
-func (t *T) F() {} // ERROR "undefined: T"
\ No newline at end of file
+func (t *T) F() {} // ERROR "undefined.*T"
\ No newline at end of file
diff --git a/test/fixedbugs/bug340.go b/test/fixedbugs/bug340.go
index a067940408..542a6eab03 100644
--- a/test/fixedbugs/bug340.go
+++ b/test/fixedbugs/bug340.go
@@ -13,6 +13,6 @@ func main() {
 	switch t := x.(type) {
 	case 0:		// ERROR "type"
 		t.x = 1
-		x.x = 1 // ERROR "type interface \{\}|reference to undefined field or method"
+		x.x = 1 // ERROR "type interface \{\}|reference to undefined field or method|interface with no methods"
 	}
 }
diff --git a/test/fixedbugs/bug487.go b/test/fixedbugs/bug487.go
index ab61a19a94..e60af6c8e2 100644
--- a/test/fixedbugs/bug487.go
+++ b/test/fixedbugs/bug487.go
@@ -14,8 +14,8 @@ func G() (int, int, int) {
 }
 
 func F() {
-	a, b := G()	// ERROR "assignment mismatch"
-	a, b = G()	// ERROR "assignment mismatch"
+	a, b := G()	// ERROR "mismatch"
+	a, b = G()	// ERROR "mismatch"
 	_, _ = a, b
 }
 
diff --git a/test/fixedbugs/bug510.dir/a.go b/test/fixedbugs/bug510.dir/a.go
new file mode 100644
index 0000000000..db1cfef366
--- /dev/null
+++ b/test/fixedbugs/bug510.dir/a.go
@@ -0,0 +1,13 @@
+// Copyright 2020 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 a
+
+import "reflect"
+
+type A = map[int] bool
+
+func F() interface{} {
+	return reflect.New(reflect.TypeOf((*A)(nil))).Elem().Interface()
+}
diff --git a/test/fixedbugs/bug510.dir/b.go b/test/fixedbugs/bug510.dir/b.go
new file mode 100644
index 0000000000..56b0201858
--- /dev/null
+++ b/test/fixedbugs/bug510.dir/b.go
@@ -0,0 +1,14 @@
+// Copyright 2020 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 main
+
+import "./a"
+
+func main() {
+	_, ok := a.F().(*map[int]bool)
+	if !ok {
+		panic("bad type")
+	}
+}
diff --git a/test/fixedbugs/bug510.go b/test/fixedbugs/bug510.go
new file mode 100644
index 0000000000..8a6da5dfd6
--- /dev/null
+++ b/test/fixedbugs/bug510.go
@@ -0,0 +1,9 @@
+// rundir
+
+// Copyright 2020 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.
+
+// Gccgo confused type descriptors for aliases.
+
+package ignored
diff --git a/test/fixedbugs/issue22822.go b/test/fixedbugs/issue22822.go
index 554b534503..27c873ab10 100644
--- a/test/fixedbugs/issue22822.go
+++ b/test/fixedbugs/issue22822.go
@@ -11,7 +11,9 @@ package main
 
 func F() {
 	slice := []int{1, 2, 3}
-	len := int(2)
-	println(len(slice)) // ERROR "cannot call non-function len .type int., declared at|cannot call non-function len"
 	_ = slice
+	len := int(2)
+	println(len(slice)) // ERROR "cannot call non-function len .type int., declared at LINE-1|cannot call non-function len"
+	const iota = 1
+	println(iota(slice)) // ERROR "cannot call non-function iota .type int., declared at LINE-1|cannot call non-function iota"
 }
diff --git a/test/fixedbugs/issue28079b.go b/test/fixedbugs/issue28079b.go
index 47cc16dfb2..9ff221baff 100644
--- a/test/fixedbugs/issue28079b.go
+++ b/test/fixedbugs/issue28079b.go
@@ -13,5 +13,5 @@ import "unsafe"
 type T [uintptr(unsafe.Pointer(nil))]int // ERROR "non-constant array bound"
 
 func f() {
-	_ = complex(1<<uintptr(unsafe.Pointer(nil)), 0)
+	_ = complex(1<<uintptr(unsafe.Pointer(nil)), 0) // ERROR "shift of type float64"
 }
diff --git a/test/fixedbugs/issue4232.go b/test/fixedbugs/issue4232.go
index 935f3820c6..30d132683a 100644
--- a/test/fixedbugs/issue4232.go
+++ b/test/fixedbugs/issue4232.go
@@ -19,7 +19,7 @@ func f() {
 	_ = a[10:10]
 	_ = a[9:12]            // ERROR "invalid slice index 12|index out of bounds"
 	_ = a[11:12]           // ERROR "invalid slice index 11|index out of bounds"
-	_ = a[1<<100 : 1<<110] // ERROR "overflows int" "invalid slice index 1 << 100|index out of bounds"
+	_ = a[1<<100 : 1<<110] // ERROR "overflows int|integer constant overflow" "invalid slice index 1 << 100|index out of bounds"
 
 	var s []int
 	_ = s[-1]  // ERROR "invalid slice index -1|index out of bounds"
@@ -30,7 +30,7 @@ func f() {
 	_ = s[10:10]
 	_ = s[9:12]
 	_ = s[11:12]
-	_ = s[1<<100 : 1<<110] // ERROR "overflows int" "invalid slice index 1 << 100|index out of bounds"
+	_ = s[1<<100 : 1<<110] // ERROR "overflows int|integer constant overflow" "invalid slice index 1 << 100|index out of bounds"
 
 	const c = "foofoofoof"
 	_ = c[-1]  // ERROR "invalid string index -1|index out of bounds"
@@ -41,7 +41,7 @@ func f() {
 	_ = c[10:10]
 	_ = c[9:12]            // ERROR "invalid slice index 12|index out of bounds"
 	_ = c[11:12]           // ERROR "invalid slice index 11|index out of bounds"
-	_ = c[1<<100 : 1<<110] // ERROR "overflows int" "invalid slice index 1 << 100|index out of bounds"
+	_ = c[1<<100 : 1<<110] // ERROR "overflows int|integer constant overflow" "invalid slice index 1 << 100|index out of bounds"
 
 	var t string
 	_ = t[-1]  // ERROR "invalid string index -1|index out of bounds"
@@ -52,5 +52,5 @@ func f() {
 	_ = t[10:10]
 	_ = t[9:12]
 	_ = t[11:12]
-	_ = t[1<<100 : 1<<110] // ERROR "overflows int" "invalid slice index 1 << 100|index out of bounds"
+	_ = t[1<<100 : 1<<110] // ERROR "overflows int|integer constant overflow" "invalid slice index 1 << 100|index out of bounds"
 }
diff --git a/test/fixedbugs/issue42876.go b/test/fixedbugs/issue42876.go
new file mode 100644
index 0000000000..67cf4919ac
--- /dev/null
+++ b/test/fixedbugs/issue42876.go
@@ -0,0 +1,18 @@
+// run
+
+// Copyright 2020 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 main
+
+var x = [4]int32{-0x7fffffff, 0x7fffffff, 2, 4}
+
+func main() {
+	if x[0] > x[1] {
+		panic("fail 1")
+	}
+	if x[2]&x[3] < 0 {
+		panic("fail 2") // Fails here
+	}
+}
diff --git a/test/fixedbugs/issue42944.go b/test/fixedbugs/issue42944.go
new file mode 100644
index 0000000000..bb947bc609
--- /dev/null
+++ b/test/fixedbugs/issue42944.go
@@ -0,0 +1,24 @@
+// errorcheck -0 -live
+
+// Copyright 2020 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.
+
+// Issue 42944: address of callee args area should only be short-lived
+// and never across a call.
+
+package p
+
+type T [10]int // trigger DUFFCOPY when passing by value, so it uses the address
+
+func F() {
+	var x T
+	var i int
+	for {
+		x = G(i) // no autotmp live at this and next calls
+		H(i, x)
+	}
+}
+
+func G(int) T
+func H(int, T)
diff --git a/test/fixedbugs/issue43099.go b/test/fixedbugs/issue43099.go
new file mode 100644
index 0000000000..16f18e5f96
--- /dev/null
+++ b/test/fixedbugs/issue43099.go
@@ -0,0 +1,34 @@
+// compile
+
+// Copyright 2020 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.
+
+// Check to make sure we don't try to constant fold a divide by zero.
+// This is a tricky test, as we need a value that's not recognized as 0
+// until lowering (otherwise it gets handled in a different path).
+
+package p
+
+func f() {
+	var i int
+	var s string
+	for i > 0 {
+		_ = s[0]
+		i++
+	}
+
+	var c chan int
+	c <- 1 % i
+}
+
+func f32() uint32 {
+	s := "\x00\x00\x00\x00"
+	c := uint32(s[0]) | uint32(s[1])<<8 | uint32(s[2])<<16 | uint32(s[3])<<24
+	return 1 / c
+}
+func f64() uint64 {
+	s := "\x00\x00\x00\x00\x00\x00\x00\x00"
+	c := uint64(s[0]) | uint64(s[1])<<8 | uint64(s[2])<<16 | uint64(s[3])<<24 | uint64(s[4])<<32 | uint64(s[5])<<40 | uint64(s[6])<<48 | uint64(s[7])<<56
+	return 1 / c
+}
diff --git a/test/fixedbugs/issue4458.go b/test/fixedbugs/issue4458.go
index 3ae9910d9e..6ac6d86db3 100644
--- a/test/fixedbugs/issue4458.go
+++ b/test/fixedbugs/issue4458.go
@@ -16,5 +16,5 @@ func (T) foo() {}
 func main() {
 	av := T{}
 	pav := &av
-	(**T).foo(&pav) // ERROR "no method foo|requires named type or pointer to named|undefined"
+	(**T).foo(&pav) // ERROR "no method .*foo|requires named type or pointer to named|undefined"
 }
diff --git a/test/fixedbugs/issue5172.go b/test/fixedbugs/issue5172.go
index 0339935b64..ed92ac6ff2 100644
--- a/test/fixedbugs/issue5172.go
+++ b/test/fixedbugs/issue5172.go
@@ -21,6 +21,6 @@ func main() {
 	go f.bar()    // ERROR "undefined"
 	defer f.bar() // ERROR "undefined"
 
-	t := T{1} // ERROR "too many values"
+	t := T{1} // ERROR "too many"
 	go t.Bar()
 }
diff --git a/test/fixedbugs/issue6977.go b/test/fixedbugs/issue6977.go
index 0f657eec41..4525e406b8 100644
--- a/test/fixedbugs/issue6977.go
+++ b/test/fixedbugs/issue6977.go
@@ -34,7 +34,7 @@ type U3 interface { M; m() }
 type U4 interface { M; M; M }
 type U5 interface { U1; U2; U3; U4 }
 
-type U6 interface { m(); m() } // ERROR "duplicate method m"
-type U7 interface { M32; m() } // ERROR "duplicate method m"
-type U8 interface { m(); M32 } // ERROR "duplicate method m"
-type U9 interface { M32; M64 } // ERROR "duplicate method m"
+type U6 interface { m(); m() } // ERROR "duplicate method .*m"
+type U7 interface { M32; m() } // ERROR "duplicate method .*m"
+type U8 interface { m(); M32 } // ERROR "duplicate method .*m"
+type U9 interface { M32; M64 } // ERROR "duplicate method .*m"
diff --git a/test/init.go b/test/init.go
index c2c25c7860..43bb3c6503 100644
--- a/test/init.go
+++ b/test/init.go
@@ -14,6 +14,6 @@ func init() {
 
 func main() {
 	init()         // ERROR "undefined.*init"
-	runtime.init() // ERROR "undefined.*runtime\.init|undefined: runtime"
+	runtime.init() // ERROR "undefined.*runtime\.init|reference to undefined name|undefined: runtime"
 	var _ = init   // ERROR "undefined.*init"
 }
diff --git a/test/initializerr.go b/test/initializerr.go
index 990ab60f96..5e2e9a91a0 100644
--- a/test/initializerr.go
+++ b/test/initializerr.go
@@ -23,7 +23,7 @@ var a2 = S { Y: 3, Z: 2, Y: 3 } // ERROR "duplicate"
 var a3 = T { S{}, 2, 3, 4, 5, 6 }	// ERROR "convert|too many"
 var a4 = [5]byte{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }	// ERROR "index|too many"
 var a5 = []byte { x: 2 }	// ERROR "index"
-var a6 = []byte{1: 1, 2: 2, 1: 3}	// ERROR "duplicate index"
+var a6 = []byte{1: 1, 2: 2, 1: 3}	// ERROR "duplicate"
 
 var ok1 = S { }	// should be ok
 var ok2 = T { S: ok1 }	// should be ok
diff --git a/test/interface/explicit.go b/test/interface/explicit.go
index 7aaaad4e48..1b7af6712b 100644
--- a/test/interface/explicit.go
+++ b/test/interface/explicit.go
@@ -47,7 +47,7 @@ func main() {
 	t = i // ERROR "incompatible|assignment$"
 
 	i = i2 // ok
-	i2 = i // ERROR "incompatible|missing N method|cannot convert"
+	i2 = i // ERROR "incompatible|missing N method"
 
 	i = I(i2)  // ok
 	i2 = I2(i) // ERROR "invalid|missing N method|cannot convert"
@@ -57,7 +57,7 @@ func main() {
 
 	// cannot type-assert non-interfaces
 	f := 2.0
-	_ = f.(int) // ERROR "non-interface type|not an interface type"
+	_ = f.(int) // ERROR "non-interface type|only valid for interface types|not an interface type"
 
 }
 
@@ -100,10 +100,7 @@ type T2 struct{}
 func (t *T2) M() {}
 func (t *T2) _() {}
 
-// Check that nothing satisfies an interface with blank methods.
-// Disabled this test as it's not clear we need this behavior.
-// See also issue #42964.
-/*
-var b1 B1 = &T2{} // "incompatible|missing _ method"
-var b2 B2 = &T2{} // "incompatible|missing _ method"
-*/
\ No newline at end of file
+// Already reported about the invalid blank interface method above;
+// no need to report about not implementing it.
+var b1 B1 = &T2{}
+var b2 B2 = &T2{}
diff --git a/test/label.go b/test/label.go
index 11716cc2c5..7deead6fba 100644
--- a/test/label.go
+++ b/test/label.go
@@ -61,5 +61,5 @@ L10:
 
 	goto L10
 
-	goto go2 // ERROR "label go2 not defined"
+	goto go2 // ERROR "label go2 not defined|reference to undefined label .*go2"
 }
diff --git a/test/label1.go b/test/label1.go
index b2e0ef09b8..a8eaecbff2 100644
--- a/test/label1.go
+++ b/test/label1.go
@@ -15,11 +15,11 @@ var x int
 func f1() {
 	switch x {
 	case 1:
-		continue // ERROR "continue is not in a loop$"
+		continue // ERROR "continue is not in a loop$|continue statement not within for"
 	}
 	select {
 	default:
-		continue // ERROR "continue is not in a loop$"
+		continue // ERROR "continue is not in a loop$|continue statement not within for"
 	}
 
 }
@@ -103,14 +103,14 @@ L5:
 		}
 	}
 
-	continue // ERROR "continue is not in a loop$"
+	continue // ERROR "continue is not in a loop$|continue statement not within for"
 	for {
-		continue on // ERROR "continue label not defined: on"
+		continue on // ERROR "continue label not defined: on|invalid continue label .*on"
 	}
 
-	break // ERROR "break is not in a loop, switch, or select"
+	break // ERROR "break is not in a loop, switch, or select|break statement not within for or switch or select"
 	for {
-		break dance // ERROR "break label not defined: dance"
+		break dance // ERROR "break label not defined: dance|invalid break label .*dance"
 	}
 
 	for {
diff --git a/test/linkname2.go b/test/linkname2.go
new file mode 100644
index 0000000000..43e66a5849
--- /dev/null
+++ b/test/linkname2.go
@@ -0,0 +1,30 @@
+// errorcheck
+
+// Copyright 2020 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.
+
+// Tests that errors are reported for misuse of linkname.
+package p
+
+import _ "unsafe"
+
+type t int
+
+var x, y int
+
+//go:linkname x ok
+
+// ERROR "//go:linkname requires linkname argument or -p compiler flag"
+// BAD: want error "//go:linkname must refer to declared function or variable"
+// BAD: want error "//go:linkname must refer to declared function or variable"
+// ERROR "duplicate //go:linkname for x"
+
+// The two BAD lines are just waiting for #42938 before we can
+// re-enable the errors.
+
+//line linkname2.go:18
+//go:linkname y
+//go:linkname nonexist nonexist
+//go:linkname t notvarfunc
+//go:linkname x duplicate
diff --git a/test/live.go b/test/live.go
index 3df7ab01af..d52ce7f007 100644
--- a/test/live.go
+++ b/test/live.go
@@ -718,5 +718,5 @@ func f44(f func() [2]*int) interface{} { // ERROR "live at entry to f44: f"
 	}
 	ret := T{}
 	ret.s[0] = f()
-	return ret // ERROR "stack object .autotmp_5 T"
+	return ret // ERROR "stack object .autotmp_[0-9]+ T"
 }
diff --git a/test/map1.go b/test/map1.go
index bd4d87b871..a6b27e6ebd 100644
--- a/test/map1.go
+++ b/test/map1.go
@@ -64,5 +64,5 @@ func main() {
 	delete()        // ERROR "missing arguments|not enough arguments"
 	delete(m)       // ERROR "missing second \(key\) argument|not enough arguments"
 	delete(m, 2, 3) // ERROR "too many arguments"
-	delete(1, m)    // ERROR "first argument to delete must be map|is not a map"
-}
\ No newline at end of file
+	delete(1, m)    // ERROR "first argument to delete must be map|argument 1 must be a map|is not a map"
+}
diff --git a/test/method2.go b/test/method2.go
index 790062c2af..2a92136d6c 100644
--- a/test/method2.go
+++ b/test/method2.go
@@ -33,9 +33,9 @@ var _ = (*Val).val // ERROR "method"
 var v Val
 var pv = &v
 
-var _ = pv.val() // ERROR "pv.val undefined"
-var _ = pv.val   // ERROR "pv.val undefined"
+var _ = pv.val() // ERROR "undefined|pointer to interface"
+var _ = pv.val   // ERROR "undefined|pointer to interface"
 
 func (t *T) g() int { return t.a }
 
-var _ = (T).g() // ERROR "needs pointer receiver|undefined|cannot call pointer method"
+var _ = (T).g() // ERROR "needs pointer receiver|undefined|method requires pointer|cannot call pointer method"
diff --git a/test/run.go b/test/run.go
index 3e0e7ab368..91bdd629bf 100644
--- a/test/run.go
+++ b/test/run.go
@@ -14,6 +14,7 @@ import (
 	"fmt"
 	"hash/fnv"
 	"io"
+	"io/fs"
 	"io/ioutil"
 	"log"
 	"os"
@@ -1869,7 +1870,7 @@ func overlayDir(dstRoot, srcRoot string) error {
 		return err
 	}
 
-	return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error {
+	return filepath.WalkDir(srcRoot, func(srcPath string, d fs.DirEntry, err error) error {
 		if err != nil || srcPath == srcRoot {
 			return err
 		}
@@ -1880,14 +1881,16 @@ func overlayDir(dstRoot, srcRoot string) error {
 		}
 		dstPath := filepath.Join(dstRoot, suffix)
 
-		perm := info.Mode() & os.ModePerm
-		if info.Mode()&os.ModeSymlink != 0 {
+		var info fs.FileInfo
+		if d.Type()&os.ModeSymlink != 0 {
 			info, err = os.Stat(srcPath)
-			if err != nil {
-				return err
-			}
-			perm = info.Mode() & os.ModePerm
+		} else {
+			info, err = d.Info()
 		}
+		if err != nil {
+			return err
+		}
+		perm := info.Mode() & os.ModePerm
 
 		// Always copy directories (don't symlink them).
 		// If we add a file in the overlay, we don't want to add it in the original.
@@ -1933,6 +1936,7 @@ var excluded = map[string]bool{
 	"import5.go":      true, // issue #42988
 	"import6.go":      true,
 	"initializerr.go": true,
+	"linkname2.go":    true,
 	"makechan.go":     true,
 	"makemap.go":      true,
 	"shift1.go":       true, // issue #42989
diff --git a/test/shift1.go b/test/shift1.go
index df0c032cd5..d6a6c38839 100644
--- a/test/shift1.go
+++ b/test/shift1.go
@@ -73,8 +73,8 @@ func _() {
 	// non constants arguments trigger a different path
 	f2 := 1.2
 	s2 := "hi"
-	_ = f2 << 2 // ERROR "shift of type float64"
-	_ = s2 << 2 // ERROR "shift of type string"
+	_ = f2 << 2 // ERROR "shift of type float64|non-integer"
+	_ = s2 << 2 // ERROR "shift of type string|non-integer"
 }
 
 // shifts in comparisons w/ untyped operands
diff --git a/test/syntax/chan1.go b/test/syntax/chan1.go
index 56103d1d79..88a5b4777b 100644
--- a/test/syntax/chan1.go
+++ b/test/syntax/chan1.go
@@ -10,8 +10,8 @@ var c chan int
 var v int
 
 func main() {
-	if c <- v { // ERROR "cannot use c <- v as value"
+	if c <- v { // ERROR "cannot use c <- v as value|send statement used as value"
 	}
 }
 
-var _ = c <- v // ERROR "unexpected <-"
+var _ = c <- v // ERROR "unexpected <-|send statement used as value"
diff --git a/test/syntax/semi4.go b/test/syntax/semi4.go
index f21431b3f5..08c354751b 100644
--- a/test/syntax/semi4.go
+++ b/test/syntax/semi4.go
@@ -8,5 +8,5 @@ package main
 
 func main() {
 	for x		// GCCGO_ERROR "undefined"
-	{		// ERROR "unexpected {, expecting for loop condition"
-		z
+	{		// ERROR "unexpected {, expecting for loop condition|expecting .*{.* after for clause"
+		z	// GCCGO_ERROR "undefined"
diff --git a/test/syntax/semi6.go b/test/syntax/semi6.go
index 4a04f89ddb..9bc730d43d 100644
--- a/test/syntax/semi6.go
+++ b/test/syntax/semi6.go
@@ -6,6 +6,6 @@
 
 package main
 
-type T1	// ERROR "unexpected newline in type declaration"
+type T1	// ERROR "newline in type declaration"
 
-type T2 /* // ERROR "unexpected EOF in type declaration" */
\ No newline at end of file
+type T2 /* // ERROR "(semicolon.*|EOF) in type declaration" */
\ No newline at end of file
diff --git a/test/used.go b/test/used.go
new file mode 100644
index 0000000000..a3f0e1270b
--- /dev/null
+++ b/test/used.go
@@ -0,0 +1,144 @@
+// errorcheck
+
+// Copyright 2020 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 p
+
+import "unsafe"
+
+const C = 1
+
+var x, x1, x2 int
+var b bool
+var s string
+var c chan int
+var cp complex128
+var slice []int
+var array [2]int
+var bytes []byte
+var runes []rune
+var r rune
+
+func f0()            {}
+func f1() int        { return 1 }
+func f2() (int, int) { return 1, 1 }
+
+type T struct{ X int }
+
+func (T) M1() int { return 1 }
+func (T) M0()     {}
+func (T) M()      {}
+
+var t T
+var tp *T
+
+type I interface{ M() }
+
+var i I
+
+var m map[int]int
+
+func _() {
+	// Note: if the next line changes to x, the error silences the x+x etc below!
+	x1 // ERROR "x1 .* not used"
+
+	nil                    // ERROR "nil .* not used"
+	C                      // ERROR  "C .* not used"
+	1                      // ERROR "1 .* not used"
+	x + x                  // ERROR "x \+ x .* not used"
+	x - x                  // ERROR "x - x .* not used"
+	x | x                  // ERROR "x \| x .* not used"
+	"a" + s                // ERROR ".a. \+ s .* not used"
+	&x                     // ERROR "&x .* not used"
+	b && b                 // ERROR "b && b .* not used"
+	append(slice, 1)       // ERROR "append\(slice, 1\) .* not used"
+	string(bytes)          // ERROR "string\(bytes\) .* not used"
+	string(runes)          // ERROR "string\(runes\) .* not used"
+	f0()                   // ok
+	f1()                   // ok
+	f2()                   // ok
+	_ = f0()               // ERROR "f0\(\) .*used as value"
+	_ = f1()               // ok
+	_, _ = f2()            // ok
+	_ = f2()               // ERROR "assignment mismatch: 1 variable but f2 returns 2 values|cannot assign"
+	T.M0                   // ERROR "T.M0 .* not used"
+	t.M0                   // ERROR "t.M0 .* not used"
+	cap                    // ERROR "use of builtin cap not in function call|must be called"
+	cap(slice)             // ERROR "cap\(slice\) .* not used"
+	close(c)               // ok
+	_ = close(c)           // ERROR "close\(c\) .*used as value"
+	func() {}              // ERROR "func literal .* not used|is not used"
+	X{}                    // ERROR "undefined: X"
+	map[string]int{}       // ERROR "map\[string\]int{} .* not used"
+	struct{}{}             // ERROR "struct ?{}{} .* not used"
+	[1]int{}               // ERROR "\[1\]int{} .* not used"
+	[]int{}                // ERROR "\[\]int{} .* not used"
+	&struct{}{}            // ERROR "&struct ?{}{} .* not used"
+	float32(x)             // ERROR "float32\(x\) .* not used"
+	I(t)                   // ERROR "I\(t\) .* not used"
+	int(x)                 // ERROR "int\(x\) .* not used"
+	copy(slice, slice)     // ok
+	_ = copy(slice, slice) // ok
+	delete(m, 1)           // ok
+	_ = delete(m, 1)       // ERROR "delete\(m, 1\) .*used as value"
+	t.X                    // ERROR "t.X .* not used"
+	tp.X                   // ERROR "tp.X .* not used"
+	t.M                    // ERROR "t.M .* not used"
+	I.M                    // ERROR "I.M .* not used"
+	i.(T)                  // ERROR "i.\(T\) .* not used"
+	x == x                 // ERROR "x == x .* not used"
+	x != x                 // ERROR "x != x .* not used"
+	x != x                 // ERROR "x != x .* not used"
+	x < x                  // ERROR "x < x .* not used"
+	x >= x                 // ERROR "x >= x .* not used"
+	x > x                  // ERROR "x > x .* not used"
+	*tp                    // ERROR "\*tp .* not used"
+	slice[0]               // ERROR "slice\[0\] .* not used"
+	m[1]                   // ERROR "m\[1\] .* not used"
+	len(slice)             // ERROR "len\(slice\) .* not used"
+	make(chan int)         // ERROR "make\(chan int\) .* not used"
+	make(map[int]int)      // ERROR "make\(map\[int\]int\) .* not used"
+	make([]int, 1)         // ERROR "make\(\[\]int, 1\) .* not used"
+	x * x                  // ERROR "x \* x .* not used"
+	x / x                  // ERROR "x / x .* not used"
+	x % x                  // ERROR "x % x .* not used"
+	x << x                 // ERROR "x << x .* not used"
+	x >> x                 // ERROR "x >> x .* not used"
+	x & x                  // ERROR "x & x .* not used"
+	x &^ x                 // ERROR "x &\^ x .* not used"
+	new(int)               // ERROR "new\(int\) .* not used"
+	!b                     // ERROR "!b .* not used"
+	^x                     // ERROR "\^x .* not used"
+	+x                     // ERROR "\+x .* not used"
+	-x                     // ERROR "-x .* not used"
+	b || b                 // ERROR "b \|\| b .* not used"
+	panic(1)               // ok
+	_ = panic(1)           // ERROR "panic\(1\) .*used as value"
+	print(1)               // ok
+	_ = print(1)           // ERROR "print\(1\) .*used as value"
+	println(1)             // ok
+	_ = println(1)         // ERROR "println\(1\) .*used as value"
+	c <- 1                 // ok
+	slice[1:1]             // ERROR "slice\[1:1\] .* not used"
+	array[1:1]             // ERROR "array\[1:1\] .* not used"
+	s[1:1]                 // ERROR "s\[1:1\] .* not used"
+	slice[1:1:1]           // ERROR "slice\[1:1:1\] .* not used"
+	array[1:1:1]           // ERROR "array\[1:1:1\] .* not used"
+	recover()              // ok
+	<-c                    // ok
+	string(r)              // ERROR "string\(r\) .* not used"
+	iota                   // ERROR "undefined: iota|cannot use iota"
+	real(cp)               // ERROR "real\(cp\) .* not used"
+	imag(cp)               // ERROR "imag\(cp\) .* not used"
+	complex(1, 2)          // ERROR "complex\(1, 2\) .* not used"
+	unsafe.Alignof(t.X)    // ERROR "unsafe.Alignof\(t.X\) .* not used"
+	unsafe.Offsetof(t.X)   // ERROR "unsafe.Offsetof\(t.X\) .* not used"
+	unsafe.Sizeof(t)       // ERROR "unsafe.Sizeof\(t\) .* not used"
+	_ = int                // ERROR "type int is not an expression|not an expression"
+	(x)                    // ERROR "x .* not used|not used"
+	_ = new(x2)            // ERROR "x2 is not a type|not a type"
+	// Disabled due to issue #43125.
+	// _ = new(1 + 1)         // DISABLED "1 \+ 1 is not a type"
+}
diff --git a/test/winbatch.go b/test/winbatch.go
index c3b48d385c..54c2fff134 100644
--- a/test/winbatch.go
+++ b/test/winbatch.go
@@ -27,11 +27,11 @@ func main() {
 	// Walk the entire Go repository source tree (without GOROOT/pkg),
 	// skipping directories that start with "." and named "testdata",
 	// and ensure all .bat files found have exact CRLF line endings.
-	err := filepath.Walk(runtime.GOROOT(), func(path string, fi os.FileInfo, err error) error {
+	err := filepath.WalkDir(runtime.GOROOT(), func(path string, d os.DirEntry, err error) error {
 		if err != nil {
 			return err
 		}
-		if fi.IsDir() && (strings.HasPrefix(fi.Name(), ".") || fi.Name() == "testdata") {
+		if d.IsDir() && (strings.HasPrefix(d.Name(), ".") || d.Name() == "testdata") {
 			return filepath.SkipDir
 		}
 		if path == filepath.Join(runtime.GOROOT(), "pkg") {
@@ -39,7 +39,7 @@ func main() {
 			// Skip it to avoid false positives. (Also see golang.org/issue/37929.)
 			return filepath.SkipDir
 		}
-		if filepath.Ext(fi.Name()) == ".bat" {
+		if filepath.Ext(d.Name()) == ".bat" {
 			enforceBatchStrictCRLF(path)
 		}
 		return nil