KT-11588 Type aliases

Resolution & expansion for type aliases.
NB: Nested type aliases capturing type parameters of outer classes are not supported yet.

compiler/testData/codegen/box/typealias/simple.kt

@@ -0,0 +1,5 @@
+typealias S = String
+
+val OK: S = "OK"
+
+fun box(): S = OK

compiler/testData/diagnostics/tests/typealias/parameterRestrictions.kt

@@ -0,0 +1,5 @@
+typealias WithVariance<<!VARIANCE_ON_TYPE_PARAMETER_NOT_ALLOWED!>in<!> X, <!VARIANCE_ON_TYPE_PARAMETER_NOT_ALLOWED!>out<!> Y> = Int
+typealias WithBounds1<T : <!BOUND_ON_TYPE_ALIAS_PARAMETER_NOT_ALLOWED!>T<!>> = Int
+typealias WithBounds2<X : <!BOUND_ON_TYPE_ALIAS_PARAMETER_NOT_ALLOWED!>Y<!>, Y : <!BOUND_ON_TYPE_ALIAS_PARAMETER_NOT_ALLOWED!>X<!>> = Int
+
+val x: WithVariance<Int, Int> = 0

compiler/testData/diagnostics/tests/typealias/parameterRestrictions.txt

@@ -0,0 +1,6 @@
+package
+
+public val x: WithVariance<kotlin.Int, kotlin.Int> [= kotlin.Int] = 0
+public typealias WithBounds1</*0*/ T : [ERROR : Cyclic upper bounds]>  = kotlin.Int
+public typealias WithBounds2</*0*/ X : [ERROR : Cyclic upper bounds], /*1*/ Y : [ERROR : Cyclic upper bounds]>  = kotlin.Int
+public typealias WithVariance</*0*/ in X, /*1*/ out Y>  = kotlin.Int

compiler/testData/diagnostics/tests/typealias/parameterSubstitution.kt

@@ -0,0 +1,8 @@
+class C<T>
+
+typealias CA<T> = C<T>
+
+val ca1: CA<Int> = C<Int>()
+val ca2: CA<CA<Int>> = C<C<Int>>()
+val ca3: CA<C<Int>> = C<C<Int>>()
+val ca4: CA<Int?> = C<Int?>()

compiler/testData/diagnostics/tests/typealias/parameterSubstitution.txt

@@ -0,0 +1,14 @@
+package
+
+public val ca1: CA<kotlin.Int> [= C<kotlin.Int>]
+public val ca2: CA<CA<kotlin.Int> [= C<kotlin.Int>]> [= C<CA<kotlin.Int> [= C<kotlin.Int>]>]
+public val ca3: CA<C<kotlin.Int>> [= C<C<kotlin.Int>>]
+public val ca4: CA<kotlin.Int?> [= C<kotlin.Int?>]
+
+public final class C</*0*/ T> {
+    public constructor C</*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
+}
+public typealias CA</*0*/ T>  = C<T>

compiler/testData/diagnostics/tests/typealias/recursive.kt

@@ -0,0 +1,4 @@
+typealias A = B
+typealias B = A
+
+val x: <!RECURSIVE_TYPEALIAS_EXPANSION!>A<!> = TODO()

compiler/testData/diagnostics/tests/typealias/recursive.txt

@@ -0,0 +1,5 @@
+package
+
+public val x: [ERROR : Recursive type alias: A]
+public typealias A = B
+public typealias B = A

compiler/testData/diagnostics/tests/typealias/simpleTypeAlias.kt

@@ -0,0 +1,8 @@
+typealias S = String
+typealias SS = S
+typealias SSS = SS
+
+val s1: SSS = ""
+val s2: SSS? = null
+val s3: List<SSS>? = null
+val s4: List<List<SSS>?>? = null

compiler/testData/diagnostics/tests/typealias/simpleTypeAlias.txt

@@ -0,0 +1,9 @@
+package
+
+public val s1: SSS [= kotlin.String] = ""
+public val s2: SSS [= kotlin.String?] = null
+public val s3: kotlin.collections.List<SSS [= kotlin.String]>? = null
+public val s4: kotlin.collections.List<kotlin.collections.List<SSS [= kotlin.String]>?>? = null
+public typealias S = kotlin.String
+public typealias SS = S
+public typealias SSS = SS

compiler/testData/diagnostics/tests/typealias/substitutionVariance.kt

@@ -0,0 +1,20 @@
+class In<in T>
+class Out<out T>
+class Inv<T>
+
+typealias In1<T> = In<T>
+typealias In2<T> = In<<!REDUNDANT_PROJECTION!>in<!> T>
+typealias In3<T> = In<<!CONFLICTING_PROJECTION!>out<!> T>
+typealias In4<T> = In<*>
+
+typealias Out1<T> = Out<T>
+typealias Out2<T> = Out<<!CONFLICTING_PROJECTION!>in<!> T>
+typealias Out3<T> = Out<<!REDUNDANT_PROJECTION!>out<!> T>
+typealias Out4<T> = Out<*>
+
+typealias Inv1<T> = Inv<T>
+typealias Inv2<T> = Inv<in T>
+typealias Inv3<T> = Inv<out T>
+typealias Inv4<T> = Inv<*>
+
+val inv1: Inv1<Int> = Inv<Int>()

compiler/testData/diagnostics/tests/typealias/substitutionVariance.txt

@@ -0,0 +1,36 @@
+package
+
+public val inv1: Inv1<kotlin.Int> [= Inv<kotlin.Int>]
+
+public final class In</*0*/ in T> {
+    public constructor In</*0*/ in 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
+}
+
+public final class Inv</*0*/ T> {
+    public constructor Inv</*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
+}
+
+public final class Out</*0*/ out T> {
+    public constructor Out</*0*/ out 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
+}
+public typealias In1</*0*/ T>  = In<T>
+public typealias In2</*0*/ T>  = In<in T>
+public typealias In3</*0*/ T>  = In<out T>
+public typealias In4</*0*/ T>  = In<*>
+public typealias Inv1</*0*/ T>  = Inv<T>
+public typealias Inv2</*0*/ T>  = Inv<in T>
+public typealias Inv3</*0*/ T>  = Inv<out T>
+public typealias Inv4</*0*/ T>  = Inv<*>
+public typealias Out1</*0*/ T>  = Out<T>
+public typealias Out2</*0*/ T>  = Out<in T>
+public typealias Out3</*0*/ T>  = Out<out T>
+public typealias Out4</*0*/ T>  = Out<*>