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if else で返す値の型が違う場合 の 型推論 #read_kotlin
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| interface I1 | |
| interface I2 | |
| class A : I1, I2 | |
| class B : I1 // A と 共通の親が I1 | |
| class C : I1, I2 // A と 共通の親が I1, I2 | |
| fun main(args: Array<String>) { | |
| // 共通の親が1つ(I1)ある場合はI1、共通の親が2つ(I1,I2)の場合はAnyに型推論される | |
| val x = if (true) A() else B() // x: I1 | |
| val y = if (true) A() else C() // y: Any | |
| val a: I1 = x | |
| val b: I1 = y // Type mismatch: inferred type is Any but I1 was expected | |
| val c: I2 = y // Type mismatch: inferred type is Any but I2 was expected | |
| } |
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Kotlinスタートブック読書勉強会 #1 (#read_kotlin)
自分がいたテーブルで帰り際に話題になって、終了後に ツイートした 内容
AとB,AとC)場合 の 型推論I1)ある場合はI1I1,I2)の場合はAnyに 型推論される