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kotlinlang

Fairly new to the PSI api, I’ve only used the IR api so far. With type resolution enabled I’m having a pretty hard time getting a function’s return type. I’m resorting to a mishmash of mutliple different BindingContext slices to determine the type, but it seems like there must be a better way.

May be a <#C7L3JB43G|compiler> question, but there they seem to have success with just
```bindingContext.get(BindingContext.EXPRESSION_TYPE_INFO, expression)```
So I’m wondering if it may be something specific to how Detekt acquires the BindingContext?

Have your tried that with Detekt? Is it working?

I have. It is returning null on a lot of different cases.

I have to check other slices and cross reference many other parts to get the full picture.

I check these slices in this order
• `bindingContext.get(BindingContext.EXPRESSION_TYPE_INFO, functionExpression)` 
• `bindingContext.get(BindingContext.EXPRESSION_TYPE_INFO, functionExpression.bodyExpression)`
• `bindingContext.get(BindingContext.EXPECTED_RETURN_TYPE, functionExpression)` 
• Get the type of the last expression in the block body (unwrapping certain expressions like returns to get the actual type other than Nothing) But then I get the true type, not the type of what’s downcast.
• If there’s a body with no statements then I assume it’s Unit, for my purposes
• If it’s _still null_ then: if its a KtNamedFunction I assume it’s Unit, otherwise it’s returning a class that isn’t in the Detekt classpath (Android SDK). Based on what I found during testing.
It _works_ but I can’t help but think there’s a better way/

I’m writing a rule that checks for CQS. It attempts to identify side effects in Query style functions.

```private fun KtNamedFunction.returnType(): KotlinType? =
    (bindingContext[BindingContext.DECLARATION_TO_DESCRIPTOR, this] as? FunctionDescriptor)?.returnType```