all: drop support for Go 1.16 and Go 1.17

testdata/slice.go

@@ -1,5 +1,7 @@
 package main
 
+import "unsafe"
+
 type MySlice [32]byte
 
 type myUint8 uint8
@@ -130,6 +132,26 @@ func main() {
 	}
 	println()
 
+	// Test conversion from array to slice.
+	slice1 := []int{1, 2, 3, 4}
+	arr1 := (*[4]int)(slice1)
+	arr1[1] = -2
+	arr1[2] = 20
+	println("slice to array pointer:", arr1[0], arr1[1], arr1[2], arr1[3])
+
+	// Test unsafe.Add.
+	arr2 := [...]int{1, 2, 3, 4}
+	*(*int)(unsafe.Add(unsafe.Pointer(&arr2[0]), unsafe.Sizeof(int(1))*1)) = 5
+	*addInt(&arr2[0], 2) = 8
+	println("unsafe.Add array:", arr2[0], arr2[1], arr2[2], arr2[3])
+
+	// Test unsafe.Slice.
+	arr3 := [...]int{1, 2, 3, 4}
+	slice3 := unsafe.Slice(&arr3[1], 3)
+	slice3[0] = 9
+	slice3[1] = 15
+	println("unsafe.Slice array:", len(slice3), cap(slice3), slice3[0], slice3[1], slice3[2])
+
 	// Verify the fix in https://github.com/tinygo-org/tinygo/pull/119
 	var unnamed [32]byte
 	var named MySlice
@@ -177,3 +199,7 @@ func makeUint32(x uint32) uint32    { return x }
 func makeUint64(x uint64) uint64    { return x }
 func makeUintptr(x uintptr) uintptr { return x }
 func makeMyUint8(x myUint8) myUint8 { return x }
+
+func addInt(ptr *int, index uintptr) *int {
+	return (*int)(unsafe.Add(unsafe.Pointer(ptr), unsafe.Sizeof(int(1))*index))
+}