Analyzer Rules

Funcky ships two sets of Roslyn analyzers that guide you towards correct and idiomatic usage of the library.

Built-in analyzers (λ0xxx) are part of the Funcky package itself and are always active. They guard against usages that we consider incorrect or unsafe.
Funcky.Analyzers (λ1xxx) is an optional package with additional style and usage rules, most of them with an automatic code fix. Install it with:
```
<PackageReference Include="Funcky.Analyzers" Version="..." PrivateAssets="all" />
```

Rules in the λ11xx range concern the FunctionalAssert helpers from the Funcky.Xunit package.

Built-in rules

Rule	Severity	Title
λ0001	Error	Disallowed use of `TryGetValue`
λ0003	Error	Member is not intended for direct usage

Rule	Severity	Title
λ1001	Warning	Use of `Enumerable.Repeat` for a single element
λ1002	Warning	Use of `Enumerable.Repeat` with no element
λ1003	Warning	Use this method with argument names
λ1004	Warning	Use `ConcatToString` instead of `JoinToString(string.Empty)`
λ1005	Warning	Prefer `GetOrElse` over `Match`
λ1006	Warning	Prefer `OrElse` over `Match`
λ1007	Warning	Prefer `SelectMany` over `Match`
λ1008	Warning	Prefer `ToNullable` over `Match`
λ1009	Error	Do not use `default` to instantiate this type
λ1010	Error	An option has either zero or one elements
λ1101	Warning	Assert can be simplified

Rule	Title	Note
λ0002	Use of `Option<T>.None()` method group	`Option<T>.None()` was replaced by the `Option<T>.None` property in 3.0. The rule and its code fix were removed once the method was gone. See the migration guide.

All rules can be configured in an .editorconfig like any other Roslyn diagnostic, for example:

[*.cs]
dotnet_diagnostic.λ1003.severity = suggestion

The only exception is λ0003, which is not configurable because the flagged members do not work outside their intended syntax.