How do I know inferred type in Kotlin?

Question

(I use Kotlin 1.1.2-2)

For example, how do I know the inferred type of expression if (boolean_value) 1 else 2.0? kotlinc-jvm doesn't show the type. javaClass also doesn't help because it shows the type of computed value not expression.

>>> (if (true) 1 else 2.0).javaClass.name
java.lang.Integer
>>> (if (false) 1 else 2.0).javaClass.name
java.lang.Double
>>> val v: Double = if (false) 1 else 2.0
error: the integer literal does not conform to the expected type Double
val v: Double = if (false) 1 else 2.0
                       ^

Answer 1

when assign the if expression with diff type result to an implicit primitive variable (variable without type definition) then the variable type is Any/T?, or an implicit variable with their direct supper class P. for example:

// case 1
val v = if (false) 1 else 2.0
//  ^--- Any
v.toInt(); // error because v is Any

// case 2
val v = if (false) 1 else null
//  ^--- Int?

// case 3
val e = if (true) java.sql.Time(1) else java.sql.Timestamp(1);
//  ^--- its type is java.util.Date     

but you can define the variable explicitly with their superclass, for example:

// case 1
val v:Number = if (false) 1 else 2.0;
v.toInt();//ok 

// case 2
val v:Int? = if (false) 1 else null;

Note: you can also using CTRL+SHIFT+P/CTRL+Q to see the variable type quickly in IDEA.