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Support expected type from explicit cast

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This commit support the following case.
Suppose we have such declaration:
  fun <T> foo(): T { ... }

Then in code we want to use it like this: `foo() as String`.
But in LV <= 1.1 we have type inference error: "Not enough
information for type parameter `T`". This error happened because we
do not use type from cast as expected type for call.

In this commit we fix this problem and use this type as expected type
in following cases:
 - our function has only one type parameter (this can be relaxed later)
 - function parameter types and extension receiver type not contains `T`

Also this fix problem with `findViewById`.
Already signature was: `fun findViewById(...): View`
and was used like: `findViewById() as MyView`.
New signature is `fun <T : View> findViewById(...): T`
and old usage was broken because of problem described above
This commit is contained in:
Stanislav Erokhin
2017-09-21 16:05:41 +03:00
committed by Ilya Gorbunov
parent ac508a510e
commit 4932fa1ddd
21 changed files with 412 additions and 1 deletions
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compiler/testData/codegen/box/reified/expectedTypeFromCast.kt
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// IGNORE_BACKEND: JS, NATIVE
// LANGUAGE_VERSION: 1.2
// WITH_RUNTIME
import kotlin.test.assertEquals
inline fun <reified T> foo(): T {
return T::class.java.getName() as T
}
fun box(): String {
val fooCall = foo() as String
assertEquals("java.lang.String", fooCall)
val safeFooCall = foo() as? String
assertEquals("java.lang.String", safeFooCall)
return "OK"
}
compiler/testData/diagnostics/tests/inference/expectedTypeAdditionalTest.kt
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+12
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// !LANGUAGE: +ExpectedTypeFromCast
fun foo() = 1
fun <T> foo() = foo() <!UNCHECKED_CAST!>as T<!>
fun <T> foo2(): T = TODO()
val test = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo2<!>().<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>plus<!>("") as String
fun <T> T.bar() = this
val barTest = "".bar() <!CAST_NEVER_SUCCEEDS!>as<!> Number
compiler/testData/diagnostics/tests/inference/expectedTypeAdditionalTest.txt
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+8
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package
public val barTest: kotlin.Number
public val test: kotlin.String
public fun foo(): kotlin.Int
public fun </*0*/ T> foo(): T
public fun </*0*/ T> foo2(): T
public fun </*0*/ T> T.bar(): T
compiler/testData/diagnostics/tests/inference/expectedTypeFromCast.kt
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+20
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// !LANGUAGE: +ExpectedTypeFromCast
fun <T> foo(): T = TODO()
fun <V> id(value: V) = value
val asString = foo() as String
val viaId = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>id<!>(<!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!>()) as String
val insideId = id(foo() as String)
val asList = foo() as List<String>
val asStarList = foo() as List<*>
val safeAs = foo() as? String
val fromIs = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!>() is String
val fromNoIs = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!>() !is String
compiler/testData/diagnostics/tests/inference/expectedTypeFromCast.txt
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+12
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package
public val asList: kotlin.collections.List<kotlin.String>
public val asStarList: kotlin.collections.List<*>
public val asString: kotlin.String
public val fromIs: kotlin.Boolean
public val fromNoIs: kotlin.Boolean
public val insideId: kotlin.String
public val safeAs: kotlin.String?
public val viaId: kotlin.String
public fun </*0*/ T> foo(): T
public fun </*0*/ V> id(/*0*/ value: V): V
compiler/testData/diagnostics/tests/inference/expectedTypeFromCastComplexExpression.kt
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+16
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// !LANGUAGE: +ExpectedTypeFromCast
package pp
class A {
fun <T> foo(): T = TODO()
companion object {
fun <T> foo2(): T = TODO()
}
}
val x = A().foo() as String
val y = A.foo2() as String
val z = pp.A.foo2() as String
compiler/testData/diagnostics/tests/inference/expectedTypeFromCastComplexExpression.txt
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+23
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package
package pp {
public val x: kotlin.String
public val y: kotlin.String
public val z: kotlin.String
public final class A {
public constructor A()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public final fun </*0*/ T> foo(): T
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
public companion object Companion {
private constructor Companion()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public final fun </*0*/ T> foo2(): T
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
}
}
compiler/testData/diagnostics/tests/inference/expectedTypeWithGenerics.kt
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+17
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// !LANGUAGE: +ExpectedTypeFromCast
class X<S> {
fun <T : S> foo(): T = TODO()
}
fun test(x: X<Number>) {
val <!UNUSED_VARIABLE!>y<!> = x.foo() as Int
}
fun <S, D: S> g() {
fun <T : S> foo(): T = TODO()
val <!UNUSED_VARIABLE!>y<!> = <!TYPE_INFERENCE_UPPER_BOUND_VIOLATED!>foo<!>() as Int
val <!UNUSED_VARIABLE!>y2<!> = foo() as D
}
compiler/testData/diagnostics/tests/inference/expectedTypeWithGenerics.txt
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+12
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package
public fun </*0*/ S, /*1*/ D : S> g(): kotlin.Unit
public fun test(/*0*/ x: X<kotlin.Number>): kotlin.Unit
public final class X</*0*/ S> {
public constructor X</*0*/ S>()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public final fun </*0*/ T : S> foo(): T
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
compiler/testData/diagnostics/tests/inference/findViewById.kt
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// !LANGUAGE: +ExpectedTypeFromCast
// !DIAGNOSTICS: -UNUSED_VARIABLE -DEBUG_INFO_LEAKING_THIS
// FILE: a/View.java
package a;
public class View {
}
// FILE: a/Test.java
package a;
public class Test {
public <T extends View> T findViewById(int id);
}
// FILE: 1.kt
package a
class X : View()
class Y<T> : View()
val xExplicit: X = Test().findViewById(0)
val xCast = Test().findViewById(0) as X
val xCastExplicitType = Test().findViewById<X>(0) as X
val xSafeCastExplicitType = Test().findViewById<X>(0) <!USELESS_CAST!>as? X<!>
val yExplicit: Y<String> = Test().findViewById(0)
val yCast = Test().findViewById(0) as Y<String>
class TestChild : Test() {
val xExplicit: X = findViewById(0)
val xCast = findViewById(0) as X
val yExplicit: Y<String> = findViewById(0)
val yCast = findViewById(0) as Y<String>
}
fun test(t: Test) {
val xExplicit: X = t.findViewById(0)
val xCast = t.findViewById(0) as X
val yExplicit: Y<String> = t.findViewById(0)
val yCast = t.findViewById(0) as Y<String>
}
fun test2(t: Test?) {
val xSafeCallSafeCast = t?.findViewById(0) as? X
val xSafeCallSafeCastExplicitType = t?.findViewById<X>(0) <!USELESS_CAST!>as? X<!>
val xSafeCallCast = t?.findViewById(0) as X
val xSafeCallCastExplicitType = t<!UNNECESSARY_SAFE_CALL!>?.<!>findViewById<X>(0) as X
}
compiler/testData/diagnostics/tests/inference/findViewById.txt
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+53
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package
package a {
public val xCast: a.X
public val xCastExplicitType: a.X
public val xExplicit: a.X
public val xSafeCastExplicitType: a.X?
public val yCast: a.Y<kotlin.String>
public val yExplicit: a.Y<kotlin.String>
public fun test(/*0*/ t: a.Test): kotlin.Unit
public fun test2(/*0*/ t: a.Test?): kotlin.Unit
public open class Test {
public constructor Test()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public open fun </*0*/ T : a.View!> findViewById(/*0*/ id: kotlin.Int): T!
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
public final class TestChild : a.Test {
public constructor TestChild()
public final val xCast: a.X
public final val xExplicit: a.X
public final val yCast: a.Y<kotlin.String>
public final val yExplicit: a.Y<kotlin.String>
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public open override /*1*/ /*fake_override*/ fun </*0*/ T : a.View!> findViewById(/*0*/ id: kotlin.Int): T!
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
public open class View {
public constructor View()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
public final class X : a.View {
public constructor X()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
public final class Y</*0*/ T> : a.View {
public constructor Y</*0*/ T>()
public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
}
}