Fix overload resolution ambiguity for types intersection

There are two different forms of types intestion:
1. Type parameters with multiple bounds
2. Smart casts

The problem was that when member scope of type intersection contained
effective duplicates and that lead to overload resolution ambiguity in
strange cases like `x.hashCode()`

For first type we do effectively the same thing as when building member
scope for class extending several interfaces: group all descriptors by
both-way-overridability relation and then choose most-specific in each
group.

For smart casts we do basically the same thing but with special
treatments:
1. From all descriptors that _equal_ to most specific we choose
   the one that works without smartcast if possible (i.e. we choose first from candidates list)
2. If smart-cast value seems to be unstable we use only member scope
   of receiver type + all descriptors from smart cast possible types
   that has incompatible signature. If we'd include all of them and
   choose one as more specific, and it would lead to false
   SMART_CAST_IMPOSIBLE (see test unstableSmartCast.kt)

 #KT-3996 Fixed
 #KT-10315 Fixed

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/conflictingReturnType.kt

@@ -0,0 +1,13 @@
+// !CHECK_TYPE
+
+interface A {
+    fun foo(): CharSequence
+}
+
+interface B {
+    fun foo(): String?
+}
+
+fun <T> test(x: T) where T : B, T : A {
+    x.<!OVERLOAD_RESOLUTION_AMBIGUITY!>foo<!>()
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/conflictingReturnType.txt

@@ -0,0 +1,17 @@
+package
+
+public fun </*0*/ T : B> test(/*0*/ x: T): kotlin.Unit where T : A
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.CharSequence
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface B {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.String?
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/flexibleTypes.kt

@@ -0,0 +1,19 @@
+// !CHECK_TYPE
+// FILE: A.java
+public interface A {
+    String foo();
+}
+
+// FILE: main.kt
+
+interface B {
+    fun foo(): String?
+}
+
+interface C {
+    fun foo(): String
+}
+
+fun <T> test(x: T) where T : B, T : A, T : C {
+    x.foo().checkType { _<String>() }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/flexibleTypes.txt

@@ -0,0 +1,25 @@
+package
+
+public /*synthesized*/ fun A(/*0*/ function: () -> kotlin.String!): A
+public fun </*0*/ T : B> test(/*0*/ x: T): kotlin.Unit where T : A, T : C
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface B {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.String?
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface C {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/mostSpecific.kt

@@ -0,0 +1,13 @@
+// !CHECK_TYPE
+
+interface A {
+    fun foo(): CharSequence?
+}
+
+interface B {
+    fun foo(): String
+}
+
+fun <T> test(x: T) where T : B, T : A {
+    x.foo().checkType { _<String>() }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/mostSpecific.txt

@@ -0,0 +1,17 @@
+package
+
+public fun </*0*/ T : B> test(/*0*/ x: T): kotlin.Unit where T : A
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.CharSequence?
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface B {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/properties.kt

@@ -0,0 +1,19 @@
+// !CHECK_TYPE
+
+interface A {
+    val foo: Any?
+}
+
+interface C: A {
+    override val foo: String?
+}
+interface B: A {
+    override var foo: String
+}
+
+fun <T> test(a: T) where T : B, T : C {
+    a.foo = ""
+    a.foo = <!NULL_FOR_NONNULL_TYPE!>null<!>
+
+    a.foo.checkType { _<String>() }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/properties.txt

@@ -0,0 +1,24 @@
+package
+
+public fun </*0*/ T : B> test(/*0*/ a: T): kotlin.Unit where T : C
+
+public interface A {
+    public abstract val foo: kotlin.Any?
+    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 interface B : A {
+    public abstract override /*1*/ var foo: kotlin.String
+    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 interface C : A {
+    public abstract override /*1*/ val foo: kotlin.String?
+    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
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/propertiesConflict.kt

@@ -0,0 +1,19 @@
+// !CHECK_TYPE
+
+interface A {
+    val foo: Any?
+}
+
+interface C: A {
+    override val foo: String
+}
+interface B: A {
+    override var foo: String?
+}
+
+fun <T> test(a: T) where T : B, T : C {
+    a.<!OVERLOAD_RESOLUTION_AMBIGUITY!>foo<!> = ""
+    a.<!OVERLOAD_RESOLUTION_AMBIGUITY!>foo<!> = null
+
+    a.<!OVERLOAD_RESOLUTION_AMBIGUITY!>foo<!>.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>checkType<!> { <!UNRESOLVED_REFERENCE!>_<!><String>() }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/propertiesConflict.txt

@@ -0,0 +1,24 @@
+package
+
+public fun </*0*/ T : B> test(/*0*/ a: T): kotlin.Unit where T : C
+
+public interface A {
+    public abstract val foo: kotlin.Any?
+    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 interface B : A {
+    public abstract override /*1*/ var foo: kotlin.String?
+    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 interface C : A {
+    public abstract override /*1*/ val foo: kotlin.String
+    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
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/simple.kt

@@ -0,0 +1,13 @@
+interface A {
+    fun foo()
+}
+
+interface C: A
+interface B: A
+
+fun <T> test(x: T) where T : C?, T : B? {
+    x?.foo()
+    if (x != null) {
+        <!DEBUG_INFO_SMARTCAST!>x<!>.foo()
+    }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/simple.txt

@@ -0,0 +1,24 @@
+package
+
+public fun </*0*/ T : C?> test(/*0*/ x: T): kotlin.Unit where T : B?
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface B : A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface C : A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/validTypeParameters.kt

@@ -0,0 +1,13 @@
+// !CHECK_TYPE
+
+interface A {
+    fun <T, E> foo(): E
+}
+
+interface B {
+    fun <Q, W> foo(): W
+}
+
+fun <T> test(x: T) where T : B, T : A {
+    x.foo<String, Int>().checkType { _<Int>() }
+}

compiler/testData/diagnostics/tests/generics/multipleBoundsMemberScope/validTypeParameters.txt

@@ -0,0 +1,17 @@
+package
+
+public fun </*0*/ T : B> test(/*0*/ x: T): kotlin.Unit where T : A
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun </*0*/ T, /*1*/ E> foo(): E
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface B {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun </*0*/ Q, /*1*/ W> foo(): W
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/generics/nullability/smartCasts.kt

@@ -27,7 +27,7 @@ fun <T : CharSequence?> foo(x: T) {
 
     if (x is String) {
         <!DEBUG_INFO_SMARTCAST!>x<!>.length
-        <!DEBUG_INFO_SMARTCAST!>x<!><!UNNECESSARY_SAFE_CALL!>?.<!>length
+        x<!UNNECESSARY_SAFE_CALL!>?.<!>length
 
         <!DEBUG_INFO_SMARTCAST!>x<!>.bar1()
         x.bar2()