[FE 1.0] Prohibit using non exhaustive if and when in rhs of elvis expression

^KT-44705
^KT-49349 Fixed

compiler/testData/diagnostics/tests/controlStructures/ifWhenWithoutElse.kt

@@ -56,8 +56,8 @@ fun g6(): Unit = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!> { true -> 42 }<!>
 fun foo1(x: String?) {
     "" + <!INVALID_IF_AS_EXPRESSION!>if<!> (true) 42
     w@while (true) {
-        x ?: if (true) break
-        x ?: when { true -> break@w }
+        x ?: <!INVALID_IF_AS_EXPRESSION_WARNING!>if<!> (true) break
+        x ?: <!NO_ELSE_IN_WHEN_WARNING!>when<!> { true -> break@w }
     }
 }
 

compiler/testData/diagnostics/tests/controlStructures/nonExhaustiveIfInElvis_after.kt

@@ -0,0 +1,30 @@
+// FIR_IDENTICAL
+// LANGUAGE: +ProhibitNonExhaustiveIfInRhsOfElvis
+// DIAGNOSTICS: -USELESS_ELVIS
+// ISSUE: KT-44705
+
+fun test_1(x: String?, y: String?) {
+    while (true) {
+        x ?: <!INVALID_IF_AS_EXPRESSION!>if<!> (y == null) break
+    }
+}
+
+fun test_2(x: String?, y: String?) {
+    while (true) {
+        val z = x ?: <!INVALID_IF_AS_EXPRESSION!>if<!> (y == null) break
+    }
+}
+
+fun test_3(x: String?, y: String?) {
+    while (true) {
+        x ?: <!NO_ELSE_IN_WHEN!>when<!> { true -> break }
+        x ?: <!NO_ELSE_IN_WHEN!>when<!> (y) { "hello" -> break }
+    }
+}
+
+fun test_4(x: String?, y: String?) {
+    while (true) {
+        val a = x ?: <!NO_ELSE_IN_WHEN!>when<!> { true -> break }
+        val b = x ?: <!NO_ELSE_IN_WHEN!>when<!> (y) { "hello" -> break }
+    }
+}

compiler/testData/diagnostics/tests/controlStructures/nonExhaustiveIfInElvis_after.txt

@@ -0,0 +1,7 @@
+package
+
+public fun test_1(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_2(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_3(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_4(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+

compiler/testData/diagnostics/tests/controlStructures/nonExhaustiveIfInElvis_before.fir.kt

@@ -0,0 +1,29 @@
+// LANGUAGE: -ProhibitNonExhaustiveIfInRhsOfElvis
+// DIAGNOSTICS: -USELESS_ELVIS
+// ISSUE: KT-44705
+
+fun test_1(x: String?, y: String?) {
+    while (true) {
+        x ?: <!INVALID_IF_AS_EXPRESSION!>if<!> (y == null) break
+    }
+}
+
+fun test_2(x: String?, y: String?) {
+    while (true) {
+        val z = x ?: <!INVALID_IF_AS_EXPRESSION!>if<!> (y == null) break
+    }
+}
+
+fun test_3(x: String?, y: String?) {
+    while (true) {
+        x ?: <!NO_ELSE_IN_WHEN!>when<!> { true -> break }
+        x ?: <!NO_ELSE_IN_WHEN!>when<!> (y) { "hello" -> break }
+    }
+}
+
+fun test_4(x: String?, y: String?) {
+    while (true) {
+        val a = x ?: <!NO_ELSE_IN_WHEN!>when<!> { true -> break }
+        val b = x ?: <!NO_ELSE_IN_WHEN!>when<!> (y) { "hello" -> break }
+    }
+}

compiler/testData/diagnostics/tests/controlStructures/nonExhaustiveIfInElvis_before.kt

@@ -0,0 +1,29 @@
+// LANGUAGE: -ProhibitNonExhaustiveIfInRhsOfElvis
+// DIAGNOSTICS: -USELESS_ELVIS
+// ISSUE: KT-44705
+
+fun test_1(x: String?, y: String?) {
+    while (true) {
+        x ?: <!INVALID_IF_AS_EXPRESSION_WARNING!>if<!> (y == null) break
+    }
+}
+
+fun test_2(x: String?, y: String?) {
+    while (true) {
+        val z = x ?: <!INVALID_IF_AS_EXPRESSION!>if<!> (y == null) break
+    }
+}
+
+fun test_3(x: String?, y: String?) {
+    while (true) {
+        x ?: <!NO_ELSE_IN_WHEN_WARNING!>when<!> { true -> break }
+        x ?: <!NO_ELSE_IN_WHEN_WARNING!>when<!> (y) { "hello" -> break }
+    }
+}
+
+fun test_4(x: String?, y: String?) {
+    while (true) {
+        val a = x ?: <!NO_ELSE_IN_WHEN!>when<!> { true -> break }
+        val b = x ?: <!NO_ELSE_IN_WHEN!>when<!> (y) { "hello" -> break }
+    }
+}

compiler/testData/diagnostics/tests/controlStructures/nonExhaustiveIfInElvis_before.txt

@@ -0,0 +1,7 @@
+package
+
+public fun test_1(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_2(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_3(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+public fun test_4(/*0*/ x: kotlin.String?, /*1*/ y: kotlin.String?): kotlin.Unit
+

compiler/testData/diagnostics/tests/smartCasts/loops/elvisIfBreakInsideWhileTrue.kt

@@ -1,6 +1,6 @@
 public fun foo(x: String?, y: String?): Int {
     while (true) {
-        x ?: if (y == null) break
+        x ?: <!INVALID_IF_AS_EXPRESSION_WARNING!>if<!> (y == null) break
         // y is nullable if x != null
         y<!UNSAFE_CALL!>.<!>length
     }