Dart targets do not build on Windows, "parent" defined inconsistently in RuleContext

In trying to investigate https://github.com/antlr/antlr4/issues/3203 I ran into another problem.

I can’t seem to get Dart targets to compile on Windows, a problem with “parent”, which is inconsistently defined as a property declared in ParserRuleContext, a field in RuleContext, a property in ParseTree, a property in Tree.

I am using the latest Flutter package and Antlr4.9.2.

$ which dart
/c/Users/kenne/Downloads/flutter_windows_2.2.3-stable/flutter/bin/dart
$ dart --version
Dart SDK version: 2.13.4 (stable) (Wed Jun 23 13:08:41 2021 +0200) on "windows_x64"
$ make
java -jar c:/users/kenne/downloads/antlr-4.9.2-complete.jar -encoding utf-8 -Dlanguage=Dart  Abnf.g4
dart pub get
Resolving dependencies...
+ _fe_analyzer_shared 23.0.0
+ analyzer 2.0.0
+ antlr4 4.9.2
+ args 2.2.0
+ async 2.8.1
+ boolean_selector 2.1.0
+ charcode 1.3.1
+ cli_util 0.3.3
+ collection 1.15.0
+ convert 3.0.1
+ coverage 1.0.3
+ crypto 3.0.1
+ file 6.1.2
+ frontend_server_client 2.1.0
+ glob 2.0.1
+ http_multi_server 3.0.1
+ http_parser 4.0.0
+ io 1.0.3
+ js 0.6.3
+ logging 1.0.1
+ matcher 0.12.10
+ meta 1.7.0
+ mime 1.0.0
+ node_preamble 2.0.1
+ package_config 2.0.0
+ path 1.8.0
+ pedantic 1.11.1
+ pool 1.5.0
+ pub_semver 2.0.0
+ shelf 1.2.0
+ shelf_packages_handler 3.0.0
+ shelf_static 1.1.0
+ shelf_web_socket 1.0.1
+ source_map_stack_trace 2.1.0
+ source_maps 0.10.10
+ source_span 1.8.1
+ stack_trace 1.10.0
+ stream_channel 2.1.0
+ string_scanner 1.1.0
+ term_glyph 1.2.0
+ test 1.17.10
+ test_api 0.4.2
+ test_core 0.4.0
+ typed_data 1.3.0
+ vm_service 7.2.0
+ watcher 1.0.0
+ web_socket_channel 2.1.0
+ webkit_inspection_protocol 1.0.0
+ yaml 3.1.0
Changed 49 dependencies!
dart compile exe cli.dart
Info: Compiling without sound null safety
AbnfParser.dart:416:7: Error: The implementation of 'parent' in the non-abstract class 'RulelistContext' does not conform to its interface.
class RulelistContext extends ParserRuleContext {
      ^^^^^^^^^^^^^^^
../../../../../AppData/Local/Pub/Cache/hosted/pub.dartlang.org/antlr4-4.9.2/lib/src/rule_context.dart:66:16: Context: The return type of the method 'RuleContext.parent' is 'RuleContext', which does not match the return type, 'ParserRuleContext', of the overridden method, 'ParserRuleContext.parent'.
 - 'RuleContext' is from 'package:antlr4/src/rule_context.dart' ('../../../../../AppData/Local/Pub/Cache/hosted/pub.dartlang.org/antlr4-4.9.2/lib/src/rule_context.dart').
 - 'ParserRuleContext' is from 'package:antlr4/src/parser_rule_context.dart' ('../../../../../AppData/Local/Pub/Cache/hosted/pub.dartlang.org/antlr4-4.9.2/lib/src/parser_rule_context.dart').
Change to a subtype of 'ParserRuleContext'.
  RuleContext? parent;
	       ^
../../../../../AppData/Local/Pub/Cache/hosted/pub.dartlang.org/antlr4-4.9.2/lib/src/parser_rule_context.dart:132:26: Context: This is the overridden method ('parent').
  ParserRuleContext? get parent {
			 ^

Over on Ubuntu, this all works fine.

ken@llano:/mnt/c/Users/kenne/Documents/GitHub/i2248/abnf/Generated$ which dart
/usr/bin/dart
ken@llano:/mnt/c/Users/kenne/Documents/GitHub/i2248/abnf/Generated$ dart --version
Dart SDK version: 2.13.3 (stable) (Unknown timestamp) on "linux_x64"
ken@llano:/mnt/c/Users/kenne/Documents/GitHub/i2248/abnf/Generated$ make
java -jar /tmp/antlr-4.9.2-complete.jar -encoding utf-8 -Dlanguage=Dart  Abnf.g4
dart pub get
Resolving dependencies... (1.3s)
+ _fe_analyzer_shared 22.0.0 (23.0.0 available)
+ analyzer 1.7.2 (2.0.0 available)
+ antlr4 4.9.2
+ args 2.2.0
+ async 2.8.1
+ boolean_selector 2.1.0
+ charcode 1.3.1
+ cli_util 0.3.3
+ collection 1.15.0
+ convert 3.0.1
+ coverage 0.15.2 (1.0.3 available)
+ crypto 3.0.1
+ file 6.1.2
+ glob 2.0.1
+ http_multi_server 3.0.1
+ http_parser 4.0.0
+ io 1.0.3
+ js 0.6.3
+ logging 0.11.4 (1.0.1 available)
+ matcher 0.12.10
+ meta 1.7.0
+ mime 1.0.0
+ node_preamble 1.4.13 (2.0.1 available)
+ package_config 2.0.0
+ path 1.8.0
+ pedantic 1.11.1
+ pool 1.5.0
+ pub_semver 2.0.0
+ shelf 1.2.0
+ shelf_packages_handler 3.0.0
+ shelf_static 1.1.0
+ shelf_web_socket 1.0.1
+ source_map_stack_trace 2.1.0
+ source_maps 0.10.10
+ source_span 1.8.1
+ stack_trace 1.10.0
+ stream_channel 2.1.0
+ string_scanner 1.1.0
+ term_glyph 1.2.0
+ test 1.16.5 (1.17.10 available)
+ test_api 0.2.19 (0.4.2 available)
+ test_core 0.3.15 (0.4.0 available)
+ typed_data 1.3.0
+ vm_service 6.2.0 (7.2.0 available)
+ watcher 1.0.0
+ web_socket_channel 2.1.0
+ webkit_inspection_protocol 0.7.5 (1.0.0 available)
+ yaml 3.1.0
Downloading pedantic 1.11.1...
Downloading meta 1.7.0...
Downloading async 2.8.1...
Downloading shelf_static 1.1.0...
Downloading convert 3.0.1...
Downloading shelf 1.2.0...
Downloading io 1.0.3...
Downloading args 2.2.0...
Downloading file 6.1.2...
Downloading analyzer 1.7.2...
Downloading cli_util 0.3.3...
Changed 48 dependencies!
dart compile exe cli.dart
Info: Compiling without sound null safety
Generated: /mnt/c/Users/kenne/Documents/GitHub/i2248/abnf/Generated/cli.exe

flutter doctor didn’t report any problems other than “Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses”.

First, I’m trying to determine if I am using the wrong version of Dart. But, the instructions for Dart targets says “From version 4.9.3 onwards antlr’s dart generated code is null sound safety compatible and sets the minimum dart sdk version to 2.12.0.”

It would be nice to mention the prereqs for the current version, 4.9.2 of Antlr.

Next, I looked at the code in the C# and Java runtimes. Those runtimes define consistently “parent” as a property, not a field. I changed the code locally to use a backing value for the property, and it seems to compile and run just fine.

$ diff -r . /c/Users/kenne/Documents/GitHub/antlr4-ubuntu/runtime/Dart/lib/src/
diff -r ./parser_rule_context.dart /c/Users/kenne/Documents/GitHub/antlr4-ubuntu/runtime/Dart/lib/src/parser_rule_context.dart
53c53
<       : super(parent_: parent, invokingState: invokingStateNumber);
---
>       : super(parent: parent, invokingState: invokingStateNumber);
diff -r ./rule_context.dart /c/Users/kenne/Documents/GitHub/antlr4-ubuntu/runtime/Dart/lib/src/rule_context.dart
64,66d63
<
<   RuleContext? parent_;
<
69,76c66
<   RuleContext? get parent {
<     return parent_;
<   }
<
<   @override
<   set parent(RuleContext? v) {
<     parent_ = v;
<   }
---
>   RuleContext? parent;
83c73
<   RuleContext({this.parent_, int? invokingState})
---
>   RuleContext({this.parent, int? invokingState})

“parent” is defined inconsistently in RuleContext. It should be implemented with a backing field. See the diffs.

[kaby76]

@lingyv-li You are likely best up to date on the Dart target. Please review. Thanks, Ken

[lingyv-li]

I think you forgot to run dart pub get under antlr4/runtime/Dart before using dart analyze