Implicit nothing / intersection types are now checked also for member functions #KT-11666 Fixed

compiler/testData/diagnostics/tests/implicitIntersection.kt

@@ -14,6 +14,8 @@ class My(b: B) {
     val <!IMPLICIT_INTERSECTION_TYPE!>x<!> = if (b is A && b is C) b else null
     // Ok: given explicitly
     val y: C? = if (b is A && b is C) <!DEBUG_INFO_SMARTCAST!>b<!> else null
+    // Error!
+    fun <!IMPLICIT_INTERSECTION_TYPE!>foo<!>(b: B) = if (b is A && b is C) b else null
 }
 
 fun bar(b: B): String {

compiler/testData/diagnostics/tests/implicitIntersection.txt

@@ -28,6 +28,7 @@ public final class My {
     public final val x: {C & A & B}?
     public final val y: C?
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(/*0*/ b: B): {C & A & B}?
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }

compiler/testData/diagnostics/tests/implicitNothing.kt

@@ -16,3 +16,21 @@ fun check() {
     // Unreachable / unused, but not implicit Nothing
     <!UNREACHABLE_CODE!>val <!UNUSED_VARIABLE!>x<!> =<!> null!!
 }
+
+class Klass {
+    fun <!IMPLICIT_NOTHING_RETURN_TYPE!>bar<!>() = null!!
+
+    val <!IMPLICIT_NOTHING_PROPERTY_TYPE!>y<!> = null!!
+
+    init {
+        fun <!IMPLICIT_NOTHING_RETURN_TYPE!>local<!>() = bar()
+        // Should be unreachable: see KT-5311
+        val z = null!!
+    }
+
+    fun foo() {
+        fun <!IMPLICIT_NOTHING_RETURN_TYPE!>local<!>() = bar()
+
+        <!UNREACHABLE_CODE!>val <!UNUSED_VARIABLE!>x<!> =<!> y
+    }
+}

compiler/testData/diagnostics/tests/implicitNothing.txt

@@ -7,3 +7,13 @@ public fun baz(): kotlin.Nothing
 public fun check(): kotlin.Unit
 public fun foo(): kotlin.Nothing
 public fun gav(): kotlin.Any
+
+public final class Klass {
+    public constructor Klass()
+    public final val y: kotlin.Nothing
+    public final fun bar(): kotlin.Nothing
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}