[analyzer] No error for some duplicate top-level declarations in augment library

[sgrekhov]

According to the Augmentation library specification

It is a compile-time error if:

• A top-level declaration in an augmentation has the same name as a declaration in the main library or another of its augmentations (unless it is an augmenting declaration, described below). This is the same error conceptually as having a name collision in one file.

But analyzer doesn't report errors for mixins, extensions and extension types. Example

// main_lib.dart
import augment 'aug_lib.dart';

class C {}

mixin M {}

enum E {e;}

void foo() {}

typedef void Foo();

typedef StringAlias = String;

int get getter => 42;

void set setter(int _) {}

extension Ext on List {}

extension type ET(int _) {}

var x = 0;

const c = 0;

main() {
  print(C);
  print(M);
  print(E);
  print(foo);
  print(Foo);
  print(StringAlias);
  print(getter);
  setter = 1;
  print(List);
  print(ET);
  print(x);
  print(c);
}

// aug_lib.dart
library augment 'main_lib.dart';

class C {} // Ok, error reported

mixin M {} // No error

enum E {e;} // Ok, error reported

void foo() {} // Ok, error reported

typedef void Foo(); // Ok, error reported

typedef StringAlias = String; // Ok, error reported

int get getter => 42; // Ok, error reported

void set setter(int _) {} // Ok, error reported

extension Ext on List {} // No error

extension type ET(int _) {} // No error

var x = 0; // Ok, error reported

const c = 0; // Ok, error reported

Tested using Dart SDK version: 3.4.0-edge.59035021cf3ceb5aecf4c85ba0affd1d6aab8fa6 (main) (Wed Mar 6 01:30:11 2024 +0000) on "linux_x64"

[bwilkerson]

Any updates?

[pq]

Friendly triage ping: any updates on this one?

[srawlins]

Friendly triage ping: any updates on this one?

[bwilkerson]

@scheglov Any updates?

[scheglov]

No.

[srawlins]

Is this P1 for the Dart 3.4 release? Is it being worked on or should someone else take it on?

[scheglov]

No, I downgraded it.

[sgrekhov]

Retested on Dart SDK version: 3.6.0-edge.a6a2c57d689c5aca7d9fadd5dbf04615246ed198 (main) (Fri Sep 13 23:29:47 2024 +0000) on "linux_x64" (augmentation libraries replaced with parts in the code above). No this issue now. Closing.