AutoAssist in Android Studio for flutter List.length property mixed with List.length() method

[rtolar]

Thanks for the feedback! If your issue is related to the Flutter framework itself,
please open an issue at
github.com/flutter/flutter.

Steps to Reproduce

List strings=["hi"];
int i = strings.l

After typing "strings.l" hit ctrl-space to bring up the auto-assist window.
The entry that is highlighted has a "P" icon (indicating a property), but shows the method signature "length (int newLength)".
It looks like the AutoAssist is mixing the ".length" property with the ".length()" method.

I would expect two separate entries in the auto-assist list. One for the .length property (with a 'P' icon), and one for the .length() method (with an 'M' icon).

Please tell us what you were doing and what went wrong

Version info

Please paste the output of running flutter doctor -v here (available from the command
line or from Tools > Flutter > Flutter Doctor). It will provide the version of the
Flutter framework as well as of the IntelliJ plugin.

Microsoft Windows [Version 10.0.17134.228]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\Users\rtola\AndroidStudioProjects\flutter_app>flutter doctor -v
[√] Flutter (Channel beta, v0.5.1, on Microsoft Windows [Version 10.0.17134.228], locale en-US)
• Flutter version 0.5.1 at C:\Users\rtola\dev\flutter
• Framework revision c7ea3ca377 (3 months ago), 2018-05-29 21:07:33 +0200
• Engine revision 1ed25ca7b7
• Dart version 2.0.0-dev.58.0.flutter-f981f09760

[√] Android toolchain - develop for Android devices (Android SDK 28.0.1)
• Android SDK at C:\Users\rtola\AppData\Local\Android\sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-28, build-tools 28.0.1
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)
• All Android licenses accepted.

[√] Android Studio (version 3.1)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 28.0.1
• Dart plugin version 173.4700
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b02)

[√] Connected devices (1 available)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

• No issues found!

C:\Users\rtola\AndroidStudioProjects\flutter_app>

[rtolar]

[jwren]

I would guess that this is by design... but I'd be guessing the exact reason why this choice was made, Konstantin?

[scheglov]

Yes, I think this is by design.

In general when we see x.foo at the beginning of a statement, we don't know what user is going to write x.foo.bar() or x.foo = bar. So, we default to the setter.

However in this case, when the expression is RHS of an assignment, the user definitely means the getter. The same is for invocation arguments. Basically anywhere except of the beginning of a statement.

Which raises the question whether it is useful even for assignments. If the user is going to assign, it is useful to let him know that there is a setter. But how often users assign vs. write x.foo.bar? Maybe we should always use getters for consistency.

For UI we could show both green / read does for properties with both getter and setter. I guess we could use ElementKind.FIELD for element in CompletionSuggestion.

[rtolar]

I'm new to Dart and Android Studio, so this may just be my unfamiliarity with both.

The way that AutoAssist shows the signature for a setter was initially confusing.
e.g. it shows:

1. Red dot (which I now understand means 'setter' vs green dot for 'getter')
2. 'P' icon (for property)
3. a method signature (e.g. length(int newLength) )

However, the method signature isn't valid code.
In other words, if I type the code that matches the method signature that AutoAssist shows me:
mylist.length(5);
It won't compile. You have to type mylist.length = 5;.

Looking in the language definition (list.dart), I see the setter in list.dart is defined as set length(int newLength);, so I get why AutoAssist shows that. It's just a bit of a cognitive mismatch between what it shows and what you have to type. But I can accept that, now that I understand how it works.

However, I don't see any way to see that there is both a getter and setter for this property in the AutoAssist.

If I start a line with mylist.len ( so that it's a LHS expression), AutoAssist only shows me the setter.
I don't see any way to see that there is a getter for this property.

Is there some way to see that there's a getter, other than leaving AndroidStudio and looking up the web docs for the class?

[devoncarew]

We may want to leave off the (int newLength) when rendering the property. For either a getter or a setter, the user won't actually type the parans (print(foo.bar) and foo.bar = '123').