Lint idea: top-level final/const variable defined without explicit type

[GregoryConrad]

This would be a nice-to-have opt-in lint. Can helpful when handling more complex types.

GOOD:

const int i = 0;
final ComplexType foo = createThing();

BAD:

const i = 0;
final foo = createThing();

Rationale: increases code readability (especially for code reviews, when you don't have an IDE handy) by having type information specified explicitly in the source code. While it is sometimes obvious (like in the case of the const int i = 0 above), it is fairly useful when dealing with non-obvious types.

[dart-github-bot]

Summary: The issue proposes a new lint rule that flags top-level final and const variables without explicit type declarations. This rule aims to improve code readability by encouraging explicit type annotations, especially for complex types.

[srawlins]

Thanks for the request. It isn't clear if you are concerned specifically about local variables or top-level variables, but we have the following existing rules:

• always_specify_types - I think this achieves what you want.
• omit_local_variable_types
• omit_obvious_local_variable_types
• specify_nonobvious_local_variable_types
• type_annotate_public_apis

What you are asking for might be akin to the "DO type annotate fields and top-level variables if the type isn't obvious" rule, for which we appear to not have a backing lint rule.

[bwilkerson]

Note that omit_obvious_local_variable_types and specify_nonobvious_local_variable_types are experimental.

[GregoryConrad]

It isn't clear if you are concerned specifically about local variables or top-level variables

I'm moreso concerned with top-level variables here.

What you are asking for might be akin to the "DO type annotate fields and top-level variables if the type isn't obvious" rule, for which we appear to not have a backing lint rule.

That is more or less what I actually want, but the type_annotate_public_apis rule linked on that page appears to not do enough of what I'd like.

To explain my thinking some more, I'd be fine with an obvious assumed type like const i = 0;, but I figured for the sake of lint implementation, the lint could just require all top-level variables to have an explicit type specified. I have no preference either way; having a lint like specify_nonobvious_local_variable_types, but for top-level variables, would also satisfy my use-case.