Inlining an expression into an ExprStmt.
Call and receive expressions can be inlined directly
(though calls to only some builtins can be reduced).
All other expressions are inlined as "_ = expr".

-- go.mod --
module testdata
go 1.12

-- a/call.go --
package a

func _() {
	call() //@ inline(re"call", call)
}

func call() int { return recv() }

-- call --
package a

func _() {
	recv() //@ inline(re"call", call)
}

func call() int { return recv() }

-- a/recv.go --
package a

func _() {
	recv() //@ inline(re"recv", recv)
}

func recv() int { return <-(chan int)(nil) }

-- recv --
package a

func _() {
	<-(chan int)(nil) //@ inline(re"recv", recv)
}

func recv() int { return <-(chan int)(nil) }

-- a/constant.go --
package a

func _() {
	constant() //@ inline(re"constant", constant)
}

func constant() int { return 0 }

-- constant --
package a

func _() {
	_ = 0 //@ inline(re"constant", constant)
}

func constant() int { return 0 }

-- a/builtin.go --
package a

func _() {
	builtin() //@ inline(re"builtin", builtin)
}

func builtin() int { return len("") }

-- builtin --
package a

func _() {
	_ = len("") //@ inline(re"builtin", builtin)
}

func builtin() int { return len("") }

-- a/copy.go --
package a

func _() {
	_copy() //@ inline(re"copy", copy)
}

func _copy() int { return copy([]int(nil), []int(nil)) }

-- copy --
package a

func _() {
	copy([]int(nil), []int(nil)) //@ inline(re"copy", copy)
}

func _copy() int { return copy([]int(nil), []int(nil)) }