Improve support of custom equals in inline classes

- Ensure that typed equals parameter's type is a star projection of
  corresponding inline class

- Make possible to declare typed equals that returns 'Nothing'

- Forbid type parameters in typed equals operator declaration

^KT-54909 fixed
^KT-54910 fixed

compiler/testData/codegen/box/inlineClasses/inlineClassEqualsOverride.fir.txt

@@ -81,8 +81,47 @@ public final class IC4 {
     public synthetic final method unbox-impl(): int
 }
 
+@kotlin.jvm.JvmInline
+@kotlin.Metadata
+public final class IC5 {
+    // source: 'inlineClassEqualsOverride.kt'
+    private final field value: int
+    private synthetic method <init>(p0: int): void
+    public synthetic final static method box-impl(p0: int): IC5
+    public static method constructor-impl(p0: int): int
+    public method equals(p0: java.lang.Object): boolean
+    public static method equals-impl(p0: int, p1: java.lang.Object): boolean
+    public final static @org.jetbrains.annotations.NotNull method equals-impl0(p0: int, p1: int): java.lang.Void
+    public final method getValue(): int
+    public method hashCode(): int
+    public static method hashCode-impl(p0: int): int
+    public method toString(): java.lang.String
+    public static method toString-impl(p0: int): java.lang.String
+    public synthetic final method unbox-impl(): int
+}
+
+@kotlin.jvm.JvmInline
+@kotlin.Metadata
+public final class IC6 {
+    // source: 'inlineClassEqualsOverride.kt'
+    private final field value: int
+    private synthetic method <init>(p0: int): void
+    public synthetic final static method box-impl(p0: int): IC6
+    public static method constructor-impl(p0: int): int
+    public final @org.jetbrains.annotations.NotNull method equals(@org.jetbrains.annotations.Nullable p0: java.lang.Object): java.lang.Void
+    public final static @org.jetbrains.annotations.NotNull method equals-impl(p0: int, @org.jetbrains.annotations.Nullable p1: java.lang.Object): java.lang.Void
+    public final static method equals-impl0(p0: int, p1: int): boolean
+    public final method getValue(): int
+    public method hashCode(): int
+    public static method hashCode-impl(p0: int): int
+    public method toString(): java.lang.String
+    public static method toString-impl(p0: int): java.lang.String
+    public synthetic final method unbox-impl(): int
+}
+
 @kotlin.Metadata
 public final class InlineClassEqualsOverrideKt {
     // source: 'inlineClassEqualsOverride.kt'
+    public synthetic final static method assertThrows(p0: kotlin.jvm.functions.Function0): boolean
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }

compiler/testData/codegen/box/inlineClasses/inlineClassEqualsOverride.kt

@@ -19,7 +19,7 @@ interface I {
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC2(val value: Int) : I {
-    override fun equals(param: IC2): Boolean {
+    override operator fun equals(param: IC2): Boolean {
         return abs(value - param.value) < 2
     }
 }
@@ -34,6 +34,26 @@ value class IC4(val value: Int) {
     override fun equals(other: Any?) = TODO()
 }
 
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class IC5(val value: Int) {
+    operator fun equals(other: IC5): Nothing = TODO()
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class IC6(val value: Int) {
+    override fun equals(other: Any?): Nothing = TODO()
+}
+
+inline fun <reified T> assertThrows(block: () -> Unit): Boolean {
+    try {
+        block.invoke()
+    } catch (t: Throwable) {
+        return t is T
+    }
+    return false
+}
+
+
 fun box() = when {
     IC1(1.0) != IC1(1.05) -> "Fail 1.1"
     (IC1(1.0) as Any) != IC1(1.05) -> "Fail 1.2"
@@ -68,5 +88,9 @@ fun box() = when {
     IC1(1.0) == Any() -> "Fail 7.1"
     (IC1(1.0) as Any) == Any() -> "Fail 7.2"
 
+    !assertThrows<NotImplementedError> { IC5(0) == IC5(1) } -> "Fail 8.1"
+    !assertThrows<NotImplementedError> { IC6(0) == IC6(1) } -> "Fail 8.2"
+
+
     else -> "OK"
 }

compiler/testData/codegen/box/inlineClasses/inlineClassEqualsOverride.txt

@@ -81,8 +81,47 @@ public final class IC4 {
     public synthetic final method unbox-impl(): int
 }
 
+@kotlin.jvm.JvmInline
+@kotlin.Metadata
+public final class IC5 {
+    // source: 'inlineClassEqualsOverride.kt'
+    private final field value: int
+    private synthetic method <init>(p0: int): void
+    public synthetic final static method box-impl(p0: int): IC5
+    public static method constructor-impl(p0: int): int
+    public method equals(p0: java.lang.Object): boolean
+    public static method equals-impl(p0: int, p1: java.lang.Object): boolean
+    public final static @org.jetbrains.annotations.NotNull method equals-impl0(p0: int, p1: int): java.lang.Void
+    public final method getValue(): int
+    public method hashCode(): int
+    public static method hashCode-impl(p0: int): int
+    public method toString(): java.lang.String
+    public static method toString-impl(p0: int): java.lang.String
+    public synthetic final method unbox-impl(): int
+}
+
+@kotlin.jvm.JvmInline
+@kotlin.Metadata
+public final class IC6 {
+    // source: 'inlineClassEqualsOverride.kt'
+    private final field value: int
+    private synthetic method <init>(p0: int): void
+    public synthetic final static method box-impl(p0: int): IC6
+    public static method constructor-impl(p0: int): int
+    public @org.jetbrains.annotations.NotNull method equals(@org.jetbrains.annotations.Nullable p0: java.lang.Object): java.lang.Void
+    public static @org.jetbrains.annotations.NotNull method equals-impl(p0: int, @org.jetbrains.annotations.Nullable p1: java.lang.Object): java.lang.Void
+    public final static method equals-impl0(p0: int, p1: int): boolean
+    public final method getValue(): int
+    public method hashCode(): int
+    public static method hashCode-impl(p0: int): int
+    public method toString(): java.lang.String
+    public static method toString-impl(p0: int): java.lang.String
+    public synthetic final method unbox-impl(): int
+}
+
 @kotlin.Metadata
 public final class InlineClassEqualsOverrideKt {
     // source: 'inlineClassEqualsOverride.kt'
+    public synthetic final static method assertThrows(p0: kotlin.jvm.functions.Function0): boolean
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }

compiler/testData/codegen/box/inlineClasses/inlineClassEqualsOverridenForCollections.kt

@@ -7,7 +7,7 @@ import kotlin.math.abs
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC(val x: Double) {
-    fun equals(other: IC): Boolean {
+    operator fun equals(other: IC): Boolean {
         return abs(x - other.x) < 0.1
     }
 

compiler/testData/codegen/box/inlineClasses/inlineClassTypedEqualsGenerics.kt

@@ -6,7 +6,7 @@
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC1<T : Number>(val x: T) {
     fun equals(other: Int) = false
-    fun equals(other: IC1<T>) = true
+    operator fun equals(other: IC1<*>) = true
 }
 
 class Generic<T, R>(val x: T, val y: R)
@@ -14,19 +14,19 @@ class Generic<T, R>(val x: T, val y: R)
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC2<T, R>(val value: Generic<T, R>) {
     fun equals(other: IC1<Double>) = false
-    fun equals(other: IC2<T, R>) = true
+    operator fun equals(other: IC2<*, *>) = true
 }
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC3<T>(val value: T) {
     fun equals(other: Int) = false
-    fun equals(other: IC3<*>) = true
+    operator fun equals(other: IC3<*>) = true
 }
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class IC4<T>(val value: T) {
     fun equals(other: String) = false
-    fun equals(other: IC4<String>) = true
+    operator fun equals(other: IC4<*>) = true
 }
 
 

compiler/testData/codegen/box/inlineClasses/inlineOverInlineWithCustomEquals.kt

@@ -6,7 +6,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class A(val x: Int) {
-    fun equals(other: A) = true
+    operator fun equals(other: A) = true
 }
 
 class C
@@ -20,13 +20,13 @@ value class B2(val x: A?)
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class D1(val x: C) {
-    fun equals(other: D1) = true
+    operator fun equals(other: D1) = true
 }
 
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class D2(val x: C?) {
-    fun equals(other: D2) = true
+    operator fun equals(other: D2) = true
 }
 
 OPTIONAL_JVM_INLINE_ANNOTATION

compiler/testData/codegen/box/inlineClasses/kt54536.kt

@@ -5,7 +5,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class A(val x: Int) {
-    fun equals(other: A) = x % 5 == other.x % 5
+    operator fun equals(other: A) = x % 5 == other.x % 5
 }
 
 OPTIONAL_JVM_INLINE_ANNOTATION

compiler/testData/diagnostics/tests/inlineClasses/inefficientEqualsOverridingInInlineClass.kt

@@ -22,7 +22,16 @@ value class IC2(val x: Int) {
 value class IC3(val x: Int) {
     override fun equals(other: Any?) = true
 
-    fun equals(other: IC3) = true
+    operator fun equals(other: IC3) = true
+
+    override fun hashCode() = 0
+}
+
+@JvmInline
+value class IC4<T>(val x: Int) {
+    override fun <!INEFFICIENT_EQUALS_OVERRIDING_IN_INLINE_CLASS!>equals<!>(other: Any?) = true
+
+    fun equals(other: IC4<T>) = true
 
     override fun hashCode() = 0
 }

compiler/testData/diagnostics/tests/inlineClasses/inefficientEqualsOverridingInInlineClass.txt

@@ -19,8 +19,18 @@ package
 @kotlin.jvm.JvmInline public final value class IC3 {
     public constructor IC3(/*0*/ x: kotlin.Int)
     public final val x: kotlin.Int
-    public final fun equals(/*0*/ other: IC3): kotlin.Boolean
+    public final operator fun equals(/*0*/ other: IC3): kotlin.Boolean
     public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
 }
+
+@kotlin.jvm.JvmInline public final value class IC4</*0*/ T> {
+    public constructor IC4</*0*/ T>(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public final fun equals(/*0*/ other: IC4<T>): kotlin.Boolean
+    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+

compiler/testData/diagnostics/tests/inlineClasses/typedEqualsOperatorDeclarationCheck.kt

@@ -0,0 +1,52 @@
+// FIR_IDENTICAL
+// WITH_STDLIB
+// !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
+// LANGUAGE: +CustomEqualsInInlineClasses
+
+
+@JvmInline
+value class IC1(val x: Int) {
+    override fun equals(other: Any?) = true
+
+    operator fun equals(other: IC1) = true
+
+    override fun hashCode() = 0
+}
+
+@JvmInline
+value class IC2(val x: Int) {
+    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC1) = true
+
+    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC2) {
+    }
+}
+
+@JvmInline
+value class IC3<T>(val x: T) {
+    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC3<T>) = true
+}
+
+@JvmInline
+value class IC4<T>(val x: T) {
+    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC4<String>) = true
+}
+
+@JvmInline
+value class IC5<T: Number>(val x: T) {
+    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: T) = true
+}
+
+@JvmInline
+value class IC6<T, R>(val x: T) {
+    operator fun<!TYPE_PARAMETERS_NOT_ALLOWED!><S1, S2><!> equals(other: IC6<*, *>) = true
+}
+
+@JvmInline
+value class IC7<T, R>(val x: T) {
+    operator fun equals(other: IC7<*, *>) = true
+}
+
+@JvmInline
+value class IC8<T, R>(val x: T) {
+    operator fun equals(other: IC8<*, *>): Nothing = TODO()
+}

compiler/testData/diagnostics/tests/inlineClasses/typedEqualsOperatorDeclarationCheck.txt

@@ -0,0 +1,74 @@
+package
+
+@kotlin.jvm.JvmInline public final value class IC1 {
+    public constructor IC1(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public final operator fun equals(/*0*/ other: IC1): kotlin.Boolean
+    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC2 {
+    public constructor IC2(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public final operator fun equals(/*0*/ other: IC1): kotlin.Boolean
+    public final operator fun equals(/*0*/ other: IC2): kotlin.Unit
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC3</*0*/ T> {
+    public constructor IC3</*0*/ T>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun equals(/*0*/ other: IC3<T>): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC4</*0*/ T> {
+    public constructor IC4</*0*/ T>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun equals(/*0*/ other: IC4<kotlin.String>): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC5</*0*/ T : kotlin.Number> {
+    public constructor IC5</*0*/ T : kotlin.Number>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun equals(/*0*/ other: T): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC6</*0*/ T, /*1*/ R> {
+    public constructor IC6</*0*/ T, /*1*/ R>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun </*0*/ S1, /*1*/ S2> equals(/*0*/ other: IC6<*, *>): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC7</*0*/ T, /*1*/ R> {
+    public constructor IC7</*0*/ T, /*1*/ R>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun equals(/*0*/ other: IC7<*, *>): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+@kotlin.jvm.JvmInline public final value class IC8</*0*/ T, /*1*/ R> {
+    public constructor IC8</*0*/ T, /*1*/ R>(/*0*/ x: T)
+    public final val x: T
+    public final operator fun equals(/*0*/ other: IC8<*, *>): kotlin.Nothing
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/inlineClasses/typedEqualsOperatorModifierInInlineClass.kt

@@ -1,22 +0,0 @@
-// FIR_IDENTICAL
-// WITH_STDLIB
-// !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
-// LANGUAGE: +CustomEqualsInInlineClasses
-
-
-@JvmInline
-value class IC1(val x: Int) {
-    override fun equals(other: Any?) = true
-
-    operator fun equals(other: IC1) = true
-
-    override fun hashCode() = 0
-}
-
-@JvmInline
-value class IC2(val x: Int) {
-    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC1) = true
-
-    <!INAPPLICABLE_OPERATOR_MODIFIER!>operator<!> fun equals(other: IC2) {
-    }
-}

compiler/testData/diagnostics/tests/inlineClasses/typedEqualsOperatorModifierInInlineClass.txt

@@ -1,20 +0,0 @@
-package
-
-@kotlin.jvm.JvmInline public final value class IC1 {
-    public constructor IC1(/*0*/ x: kotlin.Int)
-    public final val x: kotlin.Int
-    public final operator fun equals(/*0*/ other: IC1): kotlin.Boolean
-    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
-}
-
-@kotlin.jvm.JvmInline public final value class IC2 {
-    public constructor IC2(/*0*/ x: kotlin.Int)
-    public final val x: kotlin.Int
-    public final operator fun equals(/*0*/ other: IC1): kotlin.Boolean
-    public final operator fun equals(/*0*/ other: IC2): kotlin.Unit
-    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
-}