KT-9835 Completion thinks receiver is nullable when it is not

#KT-9835 Fixed

idea/idea-completion/testData/basic/common/boldOrGrayed/KT9835.kt

@@ -0,0 +1,15 @@
+interface R<T>
+
+val <T> R<T>.prop: Int get() = TODO()
+fun <T> R<T>.extFun(): Int = TODO()
+
+interface I
+
+fun foo(r: R<out I>) {
+    r.<caret>
+}
+
+// EXIST: { itemText: "prop", typeText: "Int", attributes: "bold" }
+// EXIST: { itemText: "extFun", typeText: "Int", attributes: "bold" }
+
+

idea/idea-completion/testData/basic/java/syntheticExtensions/InGenericClass.kt

@@ -2,9 +2,14 @@ fun foo(klass: Class<*>) {
     klass.<caret>
 }
 
+fun <T> Class<T>.extFun(): Class<in T> = TODO()
+
 // EXIST: simpleName
 // ABSENT: getSimpleName
 // EXIST: enclosingClass
 // ABSENT: getEnclosingClass
 // EXIST: annotations
 // ABSENT: getAnnotations
+// EXIST: superclass
+// ABSENT: getSuperclass
+// EXIST: extFun

idea/idea-completion/testData/basic/multifile/KT9835/KT9835.java

@@ -0,0 +1,4 @@
+public interface R<D extends I> {
+    int getFoo();
+    int f();
+}

idea/idea-completion/testData/basic/multifile/KT9835/KT9835.kt

@@ -0,0 +1,8 @@
+interface I
+
+fun foo(r: R<out I>) {
+    r.<caret>
+}
+
+// EXIST: { itemText: "foo", tailText: " (from getFoo())", typeText: "Int", attributes: "bold" }
+// EXIST: { itemText: "f", tailText: "()", typeText: "Int", attributes: "bold" }