More accurate handling of "always null" for receivers

compiler/testData/diagnostics/tests/smartCasts/alwaysNull.kt

@@ -2,12 +2,12 @@ fun foo(): String {
     var s: String?
     s = null
     <!DEBUG_INFO_CONSTANT!>s<!>?.length
-    <!ALWAYS_NULL!>s<!><!UNSAFE_CALL!>.<!>length
+    <!DEBUG_INFO_CONSTANT!>s<!><!UNSAFE_CALL!>.<!>length
     if (<!SENSELESS_COMPARISON!><!DEBUG_INFO_CONSTANT!>s<!> == null<!>) return <!ALWAYS_NULL!>s<!>!!
     var t: String? = "y"
     if (t == null) t = "x"
     var x: Int? = null
-    if (x == null) <!TYPE_MISMATCH!>x += null<!>
+    if (x == null) <!TYPE_MISMATCH!><!DEBUG_INFO_CONSTANT!>x<!> += null<!>
     return <!DEBUG_INFO_SMARTCAST!>t<!> + s
 }
 
@@ -15,8 +15,7 @@ fun String?.gav() {}
 
 fun bar(s: String?) {
     if (s != null) return
-    // Ideally we should have DEBUG_INFO_CONSTANT instead
-    <!ALWAYS_NULL!>s<!>.gav()
+    <!DEBUG_INFO_CONSTANT!>s<!>.gav()
     <!DEBUG_INFO_CONSTANT!>s<!> as? String
     <!DEBUG_INFO_CONSTANT!>s<!> <!USELESS_CAST!>as String?<!>
     <!ALWAYS_NULL!>s<!> as String

compiler/testData/diagnostics/tests/smartCasts/alwaysNullWithJava.kt

@@ -10,7 +10,7 @@ public class My {
 fun test() {
     val my = My.create()
     if (my == null) {
-        <!ALWAYS_NULL!>my<!>.foo()
+        <!DEBUG_INFO_CONSTANT!>my<!><!UNSAFE_CALL!>.<!>foo()
     }
 }
 

compiler/testData/diagnostics/tests/smartCasts/comparisonUnderAnd.kt

@@ -15,12 +15,12 @@ fun foo(x : String?, y : String?) {
     else {
         // y == null but x != y
         <!DEBUG_INFO_SMARTCAST!>x<!>.length
-        <!ALWAYS_NULL!>y<!><!UNSAFE_CALL!>.<!>length
+        <!DEBUG_INFO_CONSTANT!>y<!><!UNSAFE_CALL!>.<!>length
     }
     if (y == null && x != <!DEBUG_INFO_CONSTANT!>y<!>) {
         // y == null but x != y
         <!DEBUG_INFO_SMARTCAST!>x<!>.length
-        <!ALWAYS_NULL!>y<!><!UNSAFE_CALL!>.<!>length
+        <!DEBUG_INFO_CONSTANT!>y<!><!UNSAFE_CALL!>.<!>length
     }
     else {
         x<!UNSAFE_CALL!>.<!>length

compiler/testData/diagnostics/tests/smartCasts/complexComparison.kt

@@ -6,7 +6,7 @@ fun foo(x: String?, y: String?, z: String?, w: String?) {
     if (x != null || y != null || (<!DEBUG_INFO_CONSTANT!>x<!> != z && <!DEBUG_INFO_CONSTANT!>y<!> != z))
         z<!UNSAFE_CALL!>.<!>length
     else
-        <!ALWAYS_NULL!>z<!><!UNSAFE_CALL!>.<!>length
+        <!DEBUG_INFO_CONSTANT!>z<!><!UNSAFE_CALL!>.<!>length
     if (x == null || y == null || (x != z && y != z))
         z<!UNSAFE_CALL!>.<!>length
     else

compiler/testData/diagnostics/tests/smartCasts/varnotnull/assignment.kt

@@ -4,7 +4,7 @@ fun foo() {
     v = "abc"
     <!DEBUG_INFO_SMARTCAST!>v<!>.length
     v = null
-    <!ALWAYS_NULL!>v<!><!UNSAFE_CALL!>.<!>length
+    <!DEBUG_INFO_CONSTANT!>v<!><!UNSAFE_CALL!>.<!>length
     v = "abc"
     <!DEBUG_INFO_SMARTCAST!>v<!>.length
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/initialization.kt

@@ -3,5 +3,5 @@ fun foo() {
     // It is possible in principle to provide smart cast here
     v<!UNSAFE_CALL!>.<!>length
     v = null
-    <!ALWAYS_NULL!>v<!><!UNSAFE_CALL!>.<!>length
+    <!DEBUG_INFO_CONSTANT!>v<!><!UNSAFE_CALL!>.<!>length
 }

compiler/testData/diagnostics/tests/smartCasts/varnotnull/varNull.kt

@@ -1,5 +1,5 @@
 fun foo(): Int {
     var s: String? = <!VARIABLE_WITH_REDUNDANT_INITIALIZER!>"abc"<!>
     s = null
-    return <!ALWAYS_NULL!>s<!><!UNSAFE_CALL!>.<!>length
+    return <!DEBUG_INFO_CONSTANT!>s<!><!UNSAFE_CALL!>.<!>length
 }