FIR checker: warn unnecessary non-null assertions

compiler/fir/analysis-tests/testData/resolve/exhaustiveness/positive/exhaustiveWhenAndDNNType.kt

@@ -11,7 +11,7 @@ fun takeB(b: B) {}
 
 fun test_1() {
     val flag = SomeEnum.A1
-    val b: B = when (flag!!) {
+    val b: B = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         SomeEnum.A1 -> B()
         SomeEnum.A2 -> B()
     }
@@ -21,7 +21,7 @@ fun test_1() {
 fun test_2() {
     val flag = SomeEnum.A1
 
-    val b = when (flag!!) {
+    val b = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         SomeEnum.A1 -> B()
         SomeEnum.A2 -> B()
     }

compiler/fir/analysis-tests/testData/resolve/whenElse.kt

@@ -16,7 +16,7 @@ fun get(f: Boolean) = if (f) {A.A1} else {""}
 <!CONFLICTING_OVERLOADS!>fun case2()<!> {
 
     val flag: Any = get(false) //string
-    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag!!) { // should be NO_ELSE_IN_WHEN
+    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) { // should be NO_ELSE_IN_WHEN
         A.A1 -> B()
         A.A2 -> B()
     }
@@ -30,7 +30,7 @@ fun get(f: Boolean) = if (f) {A.A1} else {""}
 <!CONFLICTING_OVERLOADS!>fun case2()<!> {
 
     val flag: Any = get(true)  //A
-    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag!!) {// should be NO_ELSE_IN_WHEN
+    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {// should be NO_ELSE_IN_WHEN
         A.A1 -> B()
         A.A2 -> B()
     }
@@ -44,7 +44,7 @@ fun get(f: Boolean) = if (f) {A.A1} else {""}
 fun case3() {
 
     val flag = ""  //A
-    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag!!) {// should be NO_ELSE_IN_WHEN
+    val l1 = <!NO_ELSE_IN_WHEN!>when<!> (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {// should be NO_ELSE_IN_WHEN
         A.A1 -> B() //should be INCOMPATIBLE_TYPES
         A.A2 -> B() //should be INCOMPATIBLE_TYPES
     }

compiler/fir/analysis-tests/testData/resolve/whenExpressionType.kt

@@ -13,7 +13,7 @@ class C(val b: B)
 // TESTCASE NUMBER: 1
 fun case1() {
     val flag = A.A1
-    val l0: B = when (flag!!) {
+    val l0: B = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         A.A1 -> B()
         A.A2 -> B()
     }
@@ -34,7 +34,7 @@ fun case2() {
 fun case3() {
     val flag = A.A1
 
-    val l1 = when (flag!!) {
+    val l1 = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         A.A1 -> B()
         A.A2 -> B()
     }
@@ -68,7 +68,7 @@ fun case5() {
 // TESTCASE NUMBER: 6
 fun case6() {
     val flag: Any = A.A1
-    val l1 = when (flag!!) {
+    val l1 = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         A.A1 -> B()
         A.A2 -> B()
         else -> B()
@@ -91,7 +91,7 @@ fun case7() {
 // TESTCASE NUMBER: 8
 fun case8() {
     val flag: Any = A.A1
-    val l1: B = when (flag!!) {
+    val l1: B = when (flag<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
         A.A1 -> B()
         A.A2 -> B()
         else -> B()

compiler/fir/analysis-tests/testData/resolveWithStdlib/hashSet.kt

@@ -16,5 +16,5 @@ fun foo() {
     var c: MutableSet<String>? = null
     c = HashSet()
 
-    c!!.d = produce()
-}
+    c<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.d = produce()
+}

compiler/fir/analysis-tests/testData/resolveWithStdlib/problems/SpecialCallsWithLambdas.kt

@@ -1,4 +1,4 @@
 fun foo() {
-    val inv = {{}}!!
+    val inv = {{}}<!NOT_NULL_ASSERTION_ON_LAMBDA_EXPRESSION!>!!<!>
     val bar = {{}}
 }