Delay ForbidInferringTypeVariablesIntoEmptyIntersection to 2.*

Note: here we set sinceVersion = null for this feature. However, we plan in 1.9.* - 2.0 time frame to solve KT-56377 and to enable this feature in 2.0, the latest in 2.1.
2023-02-16 19:03:02 +01:00
parent a3dcc2032f
commit f7544aff62
34 changed files with 241 additions and 25 deletions
@@ -27,7 +27,7 @@ fun test3() = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>run<!>
    incompatibleI() // ? either uninferred T or error (Unit </: I)
 }

-fun test4() = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>run<!> {
+fun test4() = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>run<!> {
    if (p) return@run
    incompatibleC() // ? either uninferred T or error (Unit </: C)
 }
@@ -47,7 +47,7 @@ fun test(i: Inv<Nothing>, iUnit: Inv<Unit>) {

    if (iUnit is <!INCOMPATIBLE_TYPES!>String<!>) {
        launch {
-            run(A.<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>flexible<!>(iUnit)) { 42 }
+            run(A.<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>flexible<!>(iUnit)) { 42 }
        }
    }
 }
@@ -20,7 +20,7 @@ object OnlyOne {
    fun <T : Comparable<T>, S : T> greater(x: Bar<in S>, t: T) {}

    fun test(b: Bar<Long>) {
-        <!DEBUG_INFO_CALL("fqName: OnlyOne.greater; typeCall: function")!><!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>greater<!>(b, b)<!>
+        <!DEBUG_INFO_CALL("fqName: OnlyOne.greater; typeCall: function")!><!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>greater<!>(b, b)<!>
    }
 }

@@ -1,3 +1,6 @@
-/kt45461.kt:10:19: error: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, Int (multiple incompatible classes)
+/kt45461.kt:5:25: warning: parameter 'foo' is never used
+    fun <S : T> takeFoo(foo: Foo<in S>) {}
+                        ^
+/kt45461.kt:10:19: warning: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, Int (multiple incompatible classes). This will become an error in Kotlin 2.0
    Bar<String>().takeFoo(foo) // error in 1.3.72, no error in 1.4.31
                  ^
@@ -7,5 +7,5 @@ class Bar<T> {

 fun main() {
    val foo = Foo<Int>()
-    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
+    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
 }
@@ -1,4 +1,7 @@
-/kt45461_12.kt:12:19: error: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Number)
+/kt45461_12.kt:5:25: warning: parameter 'foo' is never used
+    fun <S : T> takeFoo(foo: Foo<in S>) {}
+                        ^
+/kt45461_12.kt:12:19: warning: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Number). This will become an error in Kotlin 2.0
    Bar<String>().takeFoo(foo) // error in 1.3.72, no error in 1.4.31
                  ^

@@ -9,5 +9,5 @@ interface A

 fun <K : L, L : N, N> main() where N: A, N: Number {
    val foo = Foo<K>()
-    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
+    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
 }
@@ -1,4 +1,10 @@
-/kt45461_2.kt:10:19: error: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Int)
+/kt45461_2.kt:5:25: warning: parameter 'foo' is never used
+    fun <S : T> takeFoo(foo: Foo<in S>) {}
+                        ^
+/kt45461_2.kt:8:10: warning: 'Int' is a final type, and thus a value of the type parameter is predetermined
+fun <K : Int> main() {
+         ^
+/kt45461_2.kt:10:19: warning: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Int). This will become an error in Kotlin 2.0
    Bar<String>().takeFoo(foo) // error in 1.3.72, no error in 1.4.31
                  ^

@@ -7,5 +7,5 @@ class Bar<T> {

 fun <K : <!FINAL_UPPER_BOUND!>Int<!>> main() {
    val foo = Foo<K>()
-    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
+    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
 }
@@ -1,3 +1,6 @@
-/kt45461_5.kt:10:19: error: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Number)
+/kt45461_5.kt:5:25: warning: parameter 'foo' is never used
+    fun <S : T> takeFoo(foo: Foo<in S>) {}
+                        ^
+/kt45461_5.kt:10:19: warning: type argument for a type parameter S can't be inferred because it has incompatible upper bounds: String, K (multiple incompatible classes: String, Number). This will become an error in Kotlin 2.0
    Bar<String>().takeFoo(foo) // error in 1.3.72, no error in 1.4.31
                  ^
@@ -7,5 +7,5 @@ class Bar<T> {

 fun <K : L, L : N, N: Number> main() {
    val foo = Foo<K>()
-    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
+    Bar<String>().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>takeFoo<!>(foo) // error in 1.3.72, no error in 1.4.31
 }
@@ -1,4 +1,16 @@
-/kt48765.kt:8:13: error: type argument for a type parameter T can't be inferred because it has incompatible upper bounds: String, Number (multiple incompatible classes)
+/kt48765.kt:4:44: warning: parameter 'x1' is never used
+    fun <T1: Number, T2: A<Float, T1>> foo(x1: T2, x2: T1) {}
+                                           ^
+/kt48765.kt:4:52: warning: parameter 'x2' is never used
+    fun <T1: Number, T2: A<Float, T1>> foo(x1: T2, x2: T1) {}
+                                                   ^
+/kt48765.kt:8:13: warning: type argument for a type parameter T can't be inferred because it has incompatible upper bounds: String, Number (multiple incompatible classes). This will become an error in Kotlin 2.0
        B().foo(x, foo())
            ^
+/kt48765.kt:12:9: warning: 'String' is a final type, and thus a value of the type parameter is predetermined
+fun <T: String> foo(): T  {
+        ^
+/kt48765.kt:13:15: warning: unchecked cast: String to T
+    return "" as T // this cast is safe because String is final.
+              ^

@@ -5,7 +5,7 @@ class B {
 }
 class C<T: D, T2>(val x: T, val y: T2) {
    fun test() {
-        B().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>foo<!>(x, foo())
+        B().<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>foo<!>(x, foo())
    }
 }
 open class D: A<Float, Number>()
@@ -7,5 +7,5 @@ fun <T, V> exampleGenericFunction(func: V) where T: Base, V: (T) -> Unit {

 fun main() {
    val func: (DoesNotImplementBase) -> Unit = { }
-    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>exampleGenericFunction<!>(func) // expected this to be a compilation error as the T: Base constraint should not be satisfied
+    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>exampleGenericFunction<!>(func) // expected this to be a compilation error as the T: Base constraint should not be satisfied
 }
@@ -7,5 +7,5 @@ fun <T, V> exampleGenericFunction(func: V) where T: Base, V: (T) -> Unit {

 fun main() {
    val func: (DoesNotImplementBase) -> Unit = { }
-    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>exampleGenericFunction<!>(func) // expected this to be a compilation error as the T: Base constraint should not be satisfied
+    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>exampleGenericFunction<!>(func) // expected this to be a compilation error as the T: Base constraint should not be satisfied
 }
@@ -5,7 +5,7 @@ fun box(): String {
    return try {
        val range1 = 0..1
        range1 <!CAST_NEVER_SUCCEEDS!>as<!> List<Double>
-        <!DEBUG_INFO_SMARTCAST!>range1<!>.<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>joinToString<!> { "" }
+        <!DEBUG_INFO_SMARTCAST!>range1<!>.<!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>joinToString<!> { "" }
    } catch (e: java.lang.ClassCastException) {
        "OK"
    }
@@ -1,4 +1,4 @@
-/kt49661.kt:10:5: error: type argument for a type parameter T can't be inferred because it has incompatible upper bounds: Foo, Int (multiple incompatible classes)
+/kt49661.kt:10:5: warning: type argument for a type parameter T can't be inferred because it has incompatible upper bounds: Foo, Int (multiple incompatible classes). This will become an error in Kotlin 2.0
    f<Int> { g() }
    ^

@@ -7,5 +7,5 @@ inline fun <R> f(block: ()->R?): R? {
 }

 fun main() {
-    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>f<!><Int> { g() }
+    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>f<!><Int> { g() }
 }
@@ -12,6 +12,6 @@ fun main() {
 //    val number: Long = 5 // works

    with (WrapperFunctions()) {
-        wrapper <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>greaterEq<!> number
+        wrapper <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>greaterEq<!> number
    }
 }
@@ -9,5 +9,5 @@ infix fun <T : Comparable<T>, S : T?> ExpressionWithColumnType<in S>.less(t: T)
 infix fun <T : Comparable<T>, S : T?> Expression<in S>.less(other: Expression<in S>) {}

 fun main(x: Column<Long?>, y: Double) {
-    x <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>less<!> y // error in 1.7.20, no error in 1.7.0
+    x <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>less<!> y // error in 1.7.20, no error in 1.7.0
 }
@@ -3,5 +3,5 @@ fun <T : <!FINAL_UPPER_BOUND!>String<!>> g(): T? = null
 fun <R> f(block: () -> R?): R? = block()

 fun main() {
-    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>f<!><Int> { g() /* OK, g() is inferred into {Int & String}? */ }
+    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>f<!><Int> { g() /* OK, g() is inferred into {Int & String}? */ }
 }
@@ -1,3 +1,12 @@
-/selectFromCovariantAndContravariantTypes.kt:15:5: error: type argument for a type parameter V can't be inferred because it has incompatible upper bounds: A, B (multiple incompatible classes)
+/selectFromCovariantAndContravariantTypes.kt:10:22: warning: parameter 'y' is never used
+fun <K> select(x: K, y: K): K = x
+                     ^
+/selectFromCovariantAndContravariantTypes.kt:11:19: warning: parameter 'x' is never used
+fun <V> genericIn(x: In<V>) {}
+                  ^
+/selectFromCovariantAndContravariantTypes.kt:12:20: warning: parameter 'x' is never used
+fun <V> genericOut(x: Out<V>) {}
+                   ^
+/selectFromCovariantAndContravariantTypes.kt:15:5: warning: type argument for a type parameter V can't be inferred because it has incompatible upper bounds: A, B (multiple incompatible classes). This will become an error in Kotlin 2.0
    genericIn(select(a, b))
    ^
@@ -12,7 +12,7 @@ fun <V> genericIn(x: In<V>) {}
 fun <V> genericOut(x: Out<V>) {}

 fun test1(a: In<A>, b: In<B>) {
-    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_ERROR!>genericIn<!>(select(a, b))
+    <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>genericIn<!>(select(a, b))
 }

 fun test2(a: Out<A>, b: Out<B>) {