It is an open-source, statically typed programming language supported and developed by [JetBrains](https://www.jetbrains.com/) and open-source contributors.

Some handy links:

 * [Kotlin Site](https://kotlinlang.org/)
 * [Getting Started Guide](https://kotlinlang.org/docs/tutorials/getting-started.html)
 * [Try Kotlin](https://play.kotlinlang.org/)

        bindingTrace: BindingTrace,
        componentProvider: ComponentProvider
    ): AnalysisResult? {
        // Single-module [KtFe10AnalysisHandlerExtension] can be registered without specific use-site module.
        // Simple null-check below will skip the bail-out.
        if (useSiteModule != null &&
            module.name.asString().removeSurrounding("<", ">") != useSiteModule.moduleName
        ) {

            !typeProjection.isStarProjection &&
                    typeProjection.type.hasReferenceOtherThan(allowedTypeParameterDescriptors)
        }
    }
}

/**
 * Use-site substitution override are tracked through [CallableDescriptor.getOriginal]. Note that overridden symbols are accessed through
 * [CallableDescriptor.getOverriddenDescriptors] instead, which is separate from [CallableDescriptor.getOriginal].

        unwrapUseSiteSubstitutionOverride()?.let { return it }

        unwrapInheritanceSubstitutionOverrideIfNeeded()?.let { return it }

        return null
    }

    /**
     * Use-site substitution override happens in situations like this:
     *
     * ```
     * interface List<A> { fun get(i: Int): A }
     *
     * fun take(list: List<String>) {
     *   list.get(10) // this call
     * }

            DeclaredMemberScopeKind.STATIC -> getStaticScope() ?: return null

            // Java enhancement scopes as provided by `JavaScopeProvider` are either use-site or static scopes, so we need to compose them
            // to get the combined scope. A base declared member scope with Java enhancement doesn't exist, unfortunately.
            DeclaredMemberScopeKind.COMBINED -> {

    override fun processClassifiersByNameWithSubstitution(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {
        // We have to filter out classes from supertypes because the base scope might be a use-site scope that provides inner classes from
        // supertypes.
        delegate.processClassifiersByNameWithSubstitution(name) { classifier, substitutor ->

            token,
        )
    }
    add(FirErrors.ACTUAL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE) { firDiagnostic ->
        ActualTypeAliasToClassWithDeclarationSiteVarianceImpl(
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.ACTUAL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE) { firDiagnostic ->
        ActualTypeAliasWithUseSiteVarianceImpl(

- [`KT-15470`](https://youtrack.jetbrains.com/issue/KT-15470) Inconsistency: use-site 'set' target is a compilation error, use-site 'get' target is ok
- [`KT-57179`](https://youtrack.jetbrains.com/issue/KT-57179) FIR: preserve prefix increment behavior like in K1 by calling getter twice