[FIR] Add support of multiple condition branches to exhaustiveness checker

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt

@@ -101,6 +101,12 @@ class FirWhenExhaustivenessTransformer(private val bodyResolveComponents: BodyRe
                 }
             }
         }
+
+        override fun visitBinaryLogicExpression(binaryLogicExpression: FirBinaryLogicExpression, data: EnumExhaustivenessData) {
+            if (binaryLogicExpression.kind == LogicOperationKind.OR) {
+                binaryLogicExpression.acceptChildren(this, data)
+            }
+        }
     }
 
     // ------------------------ Sealed class exhaustiveness ------------------------
@@ -147,6 +153,12 @@ class FirWhenExhaustivenessTransformer(private val bodyResolveComponents: BodyRe
             val symbol = data.symbolProvider.getSymbolByLookupTag(lookupTag) as? FirClassSymbol ?: return
             data.visitedInheritors.replace(symbol.classId, true)
         }
+
+        override fun visitBinaryLogicExpression(binaryLogicExpression: FirBinaryLogicExpression, data: SealedExhaustivenessData) {
+            if (binaryLogicExpression.kind == LogicOperationKind.OR) {
+                binaryLogicExpression.acceptChildren(this, data)
+            }
+        }
     }
 
     // ------------------------ Boolean exhaustiveness ------------------------

compiler/fir/resolve/testData/resolve/exhaustiveness_enum.kt

@@ -47,3 +47,10 @@ fun test_2(e: Enum?) {
         else -> 4
     }
 }
+
+fun test_3(e: Enum) {
+    val a = when (e) {
+        Enum.A, Enum.B -> 1
+        Enum.C -> 2
+    }
+}

compiler/fir/resolve/testData/resolve/exhaustiveness_enum.txt

@@ -120,3 +120,14 @@ FILE: exhaustiveness_enum.kt
         }
 
     }
+    public final fun test_3(e: R|Enum|): R|kotlin/Unit| {
+        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|Enum.A|) || ==($subj$, Q|Enum.B|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|Enum.C|) ->  {
+                Int(2)
+            }
+        }
+
+    }

compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.kt

@@ -37,17 +37,24 @@ fun test_2(e: Base?) {
         is C -> 3
     }
 
-    val a = when (e) {
+    val b = when (e) {
         is Base.A -> 1
         is Base.A.B -> 2
         is C -> 3
         null -> 4
     }
 
-    val a = when (e) {
+    val c = when (e) {
         is Base.A -> 1
         is Base.A.B -> 2
         is C -> 3
         else -> 4
     }
 }
+
+fun test_3(e: Base) {
+    val a = when (e) {
+        is Base.A, is Base.A.B -> 1
+        is C -> 2
+    }
+}

compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.txt

@@ -82,7 +82,7 @@ FILE: exhaustiveness_sealedClass.kt
             }
         }
 
-        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+        lval b: R|kotlin/Int| = when (R|<local>/e|) {
             ($subj$ is R|Base.A|) ->  {
                 Int(1)
             }
@@ -97,7 +97,7 @@ FILE: exhaustiveness_sealedClass.kt
             }
         }
 
-        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+        lval c: R|kotlin/Int| = when (R|<local>/e|) {
             ($subj$ is R|Base.A|) ->  {
                 Int(1)
             }
@@ -113,3 +113,14 @@ FILE: exhaustiveness_sealedClass.kt
         }
 
     }
+    public final fun test_3(e: R|Base|): R|kotlin/Unit| {
+        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+            ($subj$ is R|Base.A|) || ($subj$ is R|Base.A.B|) ->  {
+                Int(1)
+            }
+            ($subj$ is R|C|) ->  {
+                Int(2)
+            }
+        }
+
+    }