[FIR] Implement NULL_FOR_NONNULL_TYPE diagnostics, fix tests

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

@@ -1,19 +0,0 @@
-// !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
-
-    a.foo.checkType { _<String>() }
-}

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

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 
 interface A {

compiler/testData/diagnostics/tests/generics/nullability/nullToGeneric.fir.kt

@@ -1,35 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
-
-fun <E> bar(x: E) {}
-
-fun <T> foo(): T {
-    val x1: T = <!INITIALIZER_TYPE_MISMATCH!>null<!>
-    val x2: T? = null
-
-    bar<T>(<!ARGUMENT_TYPE_MISMATCH!>null<!>)
-    bar<T?>(null)
-
-    return <!RETURN_TYPE_MISMATCH!>null<!>
-}
-
-fun <T> baz(): T? = null
-
-fun <T> foobar(): T = <!RETURN_TYPE_MISMATCH!>null<!>
-
-class A<F> {
-    fun xyz(x: F) {}
-
-    fun foo(): F {
-        val x1: F = <!INITIALIZER_TYPE_MISMATCH!>null<!>
-        val x2: F? = null
-
-        xyz(<!ARGUMENT_TYPE_MISMATCH!>null<!>)
-        bar<F?>(null)
-
-        return <!RETURN_TYPE_MISMATCH!>null<!>
-    }
-
-    fun baz(): F? = null
-
-    fun foobar(): F = <!RETURN_TYPE_MISMATCH!>null<!>
-}

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

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
 
 fun <E> bar(x: E) {}

compiler/testData/diagnostics/tests/generics/varProjection/setterProjectedOutAssign.fir.kt

@@ -9,6 +9,6 @@ interface Tr<T> {
 fun test(t: Tr<*>) {
     t.v = null!!
     t.v = ""
-    t.v = null
+    t.v = <!NULL_FOR_NONNULL_TYPE!>null<!>
     t.v checkType { _<Any?>() }
 }