If then to elvis: no more allowed for if expressions with `Unit` result

idea/src/org/jetbrains/kotlin/idea/intentions/branchedTransformations/intentions/IfThenToElvisIntention.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.idea.intentions.branchedTransformations.intentions
 
 import com.intellij.openapi.editor.Editor
 import org.jetbrains.kotlin.KtNodeTypes
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
@@ -29,7 +30,6 @@ import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
-import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode.Companion.PARTIAL
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.typeUtil.TypeNullability
 import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
@@ -54,12 +54,14 @@ class IfThenToElvisIntention : SelfTargetingOffsetIndependentIntention<KtIfExpre
     }
 
     override fun isApplicableTo(element: KtIfExpression): Boolean {
+        val context = element.analyze()
+        val type = element.getType(context) ?: return false
+        if (KotlinBuiltIns.isUnit(type)) return false
+
         val condition = element.condition as? KtOperationExpression ?: return false
         val thenClause = element.then ?: return false
         val elseClause = element.`else` ?: return false
 
-        val context = condition.analyze(PARTIAL)
-
         val checkedExpression = condition.checkedExpression() ?: return false
         if (!checkedExpression.isStableVariable(context)) return false
 

idea/testData/intentions/branched/ifThenToElvis/unitResult.kt

+// IS_APPLICABLE: false
+
+open class Some {
+    fun bar() {}
+}
+
+object Obj : Some()
+
+fun foo(arg: Any?) {
+    <caret>if (arg is Some) {
+        arg.bar()
+    }
+    else {
+        Obj.bar()
+    }
+}
\ No newline at end of file

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -1452,6 +1452,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("unitResult.kt")
+            public void testUnitResult() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToElvis/unitResult.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("willNotInlineClassProperty.kt")
             public void testWillNotInlineClassProperty() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToElvis/willNotInlineClassProperty.kt");