linter A lint for shadowing members?

As an extension to https://www.dartlang.org/guides/language/effective-dart/usage#dont-use-this-when-not-needed-to-avoid-shadowing

Would it make sense to add a new lint type for (potentially unintentionally) shadowing an inherited member?

class A {
  @protected
  int get stuff => ... blah ...;
}

class B extends A {
  [either] int stuff = ... blah ...;
  
  [1000 lines later]

  void someMethod() {
    [or] int stuff = ... blah ...;
    int thingy = stuff; // I thought I was getting super.stuff
  }
}

Apr 10 '17 19:04 xster

IMHO that one just shouldn't be allowed. It's this case I think we need a lint for:

class A {
  @protected
  int get stuff => ... blah ...;
}

class B extends A {
  void someMethod() {
    int stuff;
    // 10 lines later
    int thingy = stuff; // I thought I was getting super.stuff
  }
}

...which happens in particular when you renamed A.stuff and prior to that it didn't get shadowed by the local variable.

Apr 10 '17 19:04 Hixie

cc @a14n

Apr 10 '17 19:04 Hixie

I made a rule avoid_shadowing available in https://github.com/a14n/linter/tree/avoid_shadowing branch.

The rule is perhaps a little too aggressive. It adds a lint if there's already a similar name visible (see test).

On Flutter I get 155 lints:

https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/layers/widgets/gestures.dart#L36
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/layers/widgets/sectors.dart#L34
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/layers/widgets/custom_render_box.dart#L33
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/layers/rendering/src/sector_layout.dart#L171
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/layers/raw/canvas.dart#L25
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/examples/stocks/lib/stock_arrow.dart#L17
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/devicelab/lib/framework/adb.dart#L385
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/tools/dartdoc.dart#L68
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/material_arc.dart#L233
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/material_arc.dart#L71
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/material_arc.dart#L245
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/material_arc.dart#L58
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/drag_and_drop.dart#L161
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/dev/manual_tests/overlay_geometry.dart#L34
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/test/devfs_test.dart#L416
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/application_package.dart#L83
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/application_package.dart#L112
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/application_package.dart#L180
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/application_package.dart#L163
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/base/version.dart#L54
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/base/version.dart#L56
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/base/version.dart#L55
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/base/version.dart#L67
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/ios/devices.dart#L118
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/ios/devices.dart#L101
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/ios/devices.dart#L108
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/doctor.dart#L392
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/doctor.dart#L323
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/doctor.dart#L399
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/doctor.dart#L431
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/doctor.dart#L391
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/plugins.dart#L22
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/plugins.dart#L21
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/commands/create.dart#L114
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/commands/run.dart#L190
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/commands/run.dart#L265
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/commands/fuchsia_reload.dart#L179
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/commands/fuchsia_reload.dart#L188
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/android/android_studio.dart#L83
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/android/android_studio.dart#L283
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/android/android_studio.dart#L256
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/android/android_studio.dart#L71
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/version.dart#L185
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/vmservice.dart#L255
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/vmservice.dart#L586
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_tools/lib/src/vmservice.dart#L574
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_driver/lib/src/find.dart#L191
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_driver/lib/src/find.dart#L190
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_driver/lib/src/find.dart#L95
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_test/lib/src/widget_tester.dart#L307
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_test/lib/src/binding.dart#L994
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_test/lib/src/controller.dart#L461
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter_test/lib/src/controller.dart#L471
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/test/material/material_test.dart#L44
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/switch.dart#L356
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/progress_indicator.dart#L412
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/progress_indicator.dart#L234
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/progress_indicator.dart#L89
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/input_decorator.dart#L344
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/tabs.dart#L624
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/tabs.dart#L619
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/checkbox.dart#L200
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/checkbox.dart#L183
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/bottom_navigation_bar.dart#L570
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/slider.dart#L483
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/slider.dart#L451
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/time_picker.dart#L90
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/mergeable_material.dart#L677
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/text_selection.dart#L134
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/text_selection.dart#L71
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/material/radio.dart#L199
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/overscroll_indicator.dart#L427
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/semantics_debugger.dart#L312
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/scroll_physics.dart#L73
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/scroll_physics.dart#L131
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/basic.dart#L3156
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/basic.dart#L2851
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/gesture_detector.dart#L400
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/overlay.dart#L565
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/scroll_position.dart#L223
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/heroes.dart#L111
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/pages.dart#L33
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L4058
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L4107
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L4114
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L2696
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L4122
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/framework.dart#L4071
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/layout_builder.dart#L145
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/layout_builder.dart#L132
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/page_view.dart#L58
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/page_view.dart#L72
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/page_view.dart#L244
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/page_view.dart#L83
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/widgets/page_view.dart#L188
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/painting/box_painter.dart#L471
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/painting/box_painter.dart#L453
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/painting/box_painter.dart#L1313
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/painting/box_painter.dart#L1273
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/painting/box_painter.dart#L369
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/foundation/assertions.dart#L250
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/foundation/assertions.dart#L218
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_padding.dart#L135
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_padding.dart#L133
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_padding.dart#L134
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_padding.dart#L132
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/viewport.dart#L351
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/viewport.dart#L243
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/viewport.dart#L250
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/viewport.dart#L1111
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/editable.dart#L399
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/editable.dart#L393
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L516
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L232
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L515
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L517
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L264
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/wrap.dart#L434
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_fixed_extent_list.dart#L111
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/paragraph.dart#L279
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/paragraph.dart#L260
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_grid.dart#L488
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L328
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L286
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L238
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L269
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L329
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_persistent_header.dart#L206
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L451
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L1356
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L452
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L1459
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L1923
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L1938
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/box.dart#L1975
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/table.dart#L1248
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/table.dart#L1263
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver_multi_box_adaptor.dart#L185
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/sliver.dart#L1059
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L1654
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L1780
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L2118
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L2038
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L1404
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/object.dart#L2047
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/proxy_box.dart#L272
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/semantics.dart#L510
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/block.dart#L70
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/rendering/shifted_box.dart#L317
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/activity_indicator.dart#L96
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/switch.dart#L367
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/dialog.dart#L272
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/thumb_painter.dart#L38
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/slider.dart#L310
https://github.com/flutter/flutter/blob/7b0b5c5760eaa0279782c1fa061b3d7a7acf2ba9/packages/flutter/lib/src/cupertino/slider.dart#L301

Apr 12 '17 23:04 a14n

Randomly clicked on a few. They all look reasonable. Perhaps for an extra level of leniency initially, we can omit local variables shadowing instance methods. Hopefully in those cases if a function is passed where it's expecting something else, it would crash soon enough anyway.

Apr 12 '17 23:04 xster

Yeah, shadowing instance methods is probably ok.

Apr 12 '17 23:04 Hixie

Actually I clicked on a few more and none of those were methods so maybe that's not helpful.

I wonder what the right heuristic is. Having a local variable called Size that overrides the instance field "size" is fine. Having a local variable "widget" that overrides the instance field "widget" is not... but why not?

Apr 12 '17 23:04 Hixie

Similarly I had the mixed feeling about the lines linted.

However I can imagine some people happy with this rule as it is today. If I look at Checkstyle in the Java world there's a HiddenFieldCheck that has a similar heuristic (that also applies to the parameter names - I should perhaps add their checkings to the rule)

Apr 13 '17 06:04 a14n

I just ran into a case today where this would have helped during a refactor, +1 to the lint.

My specific case was shadowing an instance field with a local variable on accident.

Apr 18 '17 16:04 jakemac53

@a14n curious if there has been any progress on this?

Jan 19 '18 17:01 jakemac53

@jakemac53 I just opened #872 to add an avoid_shadowing rule. It would be great if you can run this ne rule on your project and see if it is fine or if you see some pattern to customize.

Running it on flutter lints the following lines:

@Hixie @xster does the results look good to you?

Jan 23 '18 08:01 a14n

I just looked at a couple of places and had some half-baked thoughts.

I found several lints for code similar to the following:

final double currentTheta = this.currentTheta;

Seems like a fairly common pattern used to avoid invoking a potentially expensive method multiple times when the author is confident that the result of the invoked method won't change during the invocation of the containing method. Perhaps the lint should allow the shadowing if the local name is initialized by invoking the shadowed name.

final Version version = new Version.parse(versionText);

It's also fairly common (though not necessarily good practice) to given variables names that are the same as the type of the variable. Perhaps the lint should allow this pattern as well.

Finally, I wonder whether users really care about following this rule in test code, or whether this rule should limit itself to production code.

Having a local variable called "size" that overrides the instance field "size" is fine. Having a local variable "widget" that overrides the instance field "widget" is not... but why not?

I can think of a couple of possible reasons, though I won't pretend to know which if any are valid.

First, it's possible that some names, such as "size", "length", and "name", are generic enough and common enough that we just expect them to be used as local variable names even when they are also used as member names. Having that expectation might make it easier for us to deal with the cognitive load from shadowing. On the other hand, a name like "widget", while both generic and common, has a specific enough meaning in this context that perhaps it negates that expectation.

Another possibility is that it has less to do with the name and more to do with the perceived complexity of the type of the variable. Perhaps we deal better with shadowing simple types than we do with shadowing complex types.

Jan 23 '18 17:01 bwilkerson

Perhaps the lint should allow the shadowing if the local name is initialized by invoking the shadowed name.

I think we should allow this.

Jan 24 '18 06:01 natebosch

With the exclusion pattern var x = this.x; Flutter has the 82 below lints (121 without the pattern).

Jan 24 '18 21:01 a14n

Another pattern that we should allow:

String get someValue {
  final someValue = new StringBuffer();
  ...
  return '$someValue';
}

So we should allow shadowing a property inside the implementation of that property.

Jan 25 '18 00:01 natebosch

+1 for this feature. It would be useful in certain instances where code has been refactored.

e.g. https://github.com/dart-lang/language/issues/737

Dec 12 '19 22:12 krp

Does this include closure variable shadowing? I just found a nasty bug that looks something like this (identifier names have been changed to protect their identities):

void prepareDeliciousMeal(Fridge f) {
  final e = f.getSausage();

  // ... more code ...

  final ingredients = f.everything
      .where((e) => e.goesWellWith.contains(e.id));
  cook(ingredients);
}

If this is not the bug for this, just let me know, I'll create another one.

Jul 01 '20 20:07 filiph

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A lint for shadowing members?

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