Why is it important to specify the return type in an inline function?

In Kotlin (Android), specifying the return type in inline functions is important for clarity and correct compiler operation. Inline functions are compiled with code substitution, and explicitly specifying the type helps avoid ambiguities and errors during type inference.

Additionally, if a function returns a lambda or is used with reified types, specifying the return type guarantees correct typing and optimization.

Example:

inline fun <T> runOperation(operation: () -> T): T {
    return operation()
}

Here, the : T specification helps the compiler understand that the function returns the result of the lambda.