Everywhere including examples, external interop APIs, bindings generators
code and in other valuable places. A couple of `interface{}` usages are
intentionally left in the CHANGELOG.md, documentation and tests.
In case of ellipsis usage compiler defines argument type as ArrayT
(which is correct, because it's a natural representation of the last
argument, it represents the array of interface{}).
Here goes the problem:
```
=== RUN TestEventWarnings/variadic_event_args_via_ellipsis
compiler_test.go:251:
Error Trace: compiler_test.go:251
Error: Received unexpected error:
event 'Event' should have 'Integer' as type of 1 parameter, got: Array
Test: TestEventWarnings/variadic_event_args_via_ellipsis
```
Parsing the last argument in this case is a separate complicated problem
due to the fact that we need to grab types of elements of []interface{} inside the
fully qualified ast node which may looks like:
```
runtime.Notify("Event", (append([]interface{}{1, 2}, (([]interface{}{someVar, 4}))...))...)
```
Temporary solution is to exclude such notifications from analysis until we're
able to properly resolve element types of []interface{}.
It's possible that declared manifest event has parameter of AnyT for
those cases when parameter type differs from method to method. If so,
then we don't need to enforce type check after compilation.
So that (*codegen).Visit is able to omit code generation for these
unused global vars. The most tricky part is to detect unused global
variables, it is done in several steps:
1. Collect the set of named used/unused global vars.
2. Collect the set of globally declared expressions that contain
function calls.
3. Pick up global vars from the set made at step 2.
4. Traverse used functions and puck up those global vars that are used
from these functions.
5. Rename all globals that are presented in the set made at step 1
but are not presented in the set made on step 3 or step 4.
Move all auxiliary function declaration after Main, so that INITSLOT
instructions counter works properly. `vmAndCompileInterop` loads program
and moves nextIP to the Main function offset if there's no _init
function. If _init is there, then nextIP will be moved to the start of
_init. In TestInline we don't handle instructions properly (CALL/JMP
don't change nextIP), we just perform instruction traversal from the
start point via Next(), thus INITSLOT counter value depends on the
starting instruction, which depends on _init presence.
If variable is unnamed and does not contain function call then it's
treated as unused and code generation may be omitted for it
initialization/declaration.
In case if global var is unnamed (and, as a consequence, unused) and
contains a function call inside its value specification, we need to emit
code for this var to be able to call the function as it can have
side-effects. See the example:
```
package foo
import "github.com/nspcc-dev/neo-go/pkg/interop/runtime"
var A = f()
func Main() int {
return 3
}
func f() int {
runtime.Notify("Valuable notification", 1)
return 2
}
```
An attempt to compile the following code leads to runtime panic:
```
package foo
type CustomInt int
func Main() int {
var i CustomInt
i = 5
return i.Do(2)
}
func (CustomInt) Do(arg int) int {
return arg
}
```
The panic:
```
panic: runtime error: index out of range [0] with length 0 [recovered]
panic: runtime error: index out of range [0] with length 0
goroutine 22 [running]:
testing.tRunner.func1.2({0xa341c0, 0xc0001606d8})
/usr/local/go/src/testing/testing.go:1209 +0x24e
testing.tRunner.func1()
/usr/local/go/src/testing/testing.go:1212 +0x218
panic({0xa341c0, 0xc0001606d8})
/usr/local/go/src/runtime/panic.go:1038 +0x215
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).convertFuncDecl(0xc00015e3c0, {0xc753b8, 0xc000152c80}, 0xc000266300, 0x30)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:497 +0x10b3
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).compile.func2(0xc000152c80, 0xc00023c410)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:2153 +0x3f8
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).ForEachFile.func1(0xc000229b80)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:102 +0x82
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).ForEachPackage(0xc00015e3c0, 0xc000189bb0)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:93 +0xc6
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).ForEachFile(0x999a20, 0xc000130d80)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:99 +0x45
github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).compile(0xc00015e3c0, 0xc0002669f0, 0x1)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:2140 +0x445
github.com/nspcc-dev/neo-go/pkg/compiler.codeGen(0xc0002669f0)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:2191 +0x353
github.com/nspcc-dev/neo-go/pkg/compiler.CompileWithOptions({0xa6f39a, 0x50b6b3}, {0xc6d1a0, 0xc0002421e0}, 0x0)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:218 +0x65
github.com/nspcc-dev/neo-go/pkg/compiler_test.vmAndCompileInterop(0x5648df, {0xa9bf23, 0x94})
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/vm_test.go:75 +0x113
github.com/nspcc-dev/neo-go/pkg/compiler_test.eval(0xc0002421c0, {0xa9bf23, 0x61be8c7}, {0xa68880, 0xc0002421c0})
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/vm_test.go:36 +0x2d
github.com/nspcc-dev/neo-go/pkg/compiler_test.TestUnnamedMethodReceiver(0x4079f9)
/home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/function_call_test.go:400 +0x4f
testing.tRunner(0xc000204b60, 0xbcebb0)
/usr/local/go/src/testing/testing.go:1259 +0x102
created by testing.(*T).Run
/usr/local/go/src/testing/testing.go:1306 +0x35a
```
The solution is to use the same approach as for unnamed function
parameters handling introduced in #2204. (c *funcScope).newVariable is
able to properly handle "_" receiver.
