Don't suggest "if to ?." without else when used in expression position

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

@@ -18,13 +18,13 @@ package org.jetbrains.kotlin.idea.intentions.branchedTransformations.intentions
 
 import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.openapi.editor.Editor
-import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
 import org.jetbrains.kotlin.idea.intentions.SelfTargetingOffsetIndependentIntention
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.*
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsExpression
 
 class IfThenToSafeAccessInspection : IntentionBasedInspection<KtIfExpression>(IfThenToSafeAccessIntention::class) {
     override fun inspectionTarget(element: KtIfExpression) = element.ifKeyword
@@ -70,7 +70,9 @@ class IfThenToSafeAccessIntention : SelfTargetingOffsetIndependentIntention<KtIf
     }
 
     private fun IfThenToSelectData.clausesReplaceableBySafeCall(): Boolean {
-        if (baseClause == null || negatedClause != null && !negatedClause.isNullExpression()) return false
+        if (baseClause == null) return false
+        if (negatedClause == null && baseClause.isUsedAsExpression(context)) return false
+        if (negatedClause != null && !negatedClause.isNullExpression()) return false
         return baseClause.evaluatesTo(receiverExpression) ||
                baseClause.hasFirstReceiverOf(receiverExpression) && !baseClause.hasNullableType(context)
     }

idea/testData/intentions/branched/ifThenToSafeAccess/noElseBlockAsExpression.kt

@@ -0,0 +1,14 @@
+// IS_APPLICABLE: false
+// ERROR: 'if' must have both main and 'else' branches if used as an expression
+// ERROR: Type mismatch: inferred type is Unit but Int was expected
+
+fun maybeFoo(): String? {
+    return "foo"
+}
+
+fun bar(): Int {
+    val foo = maybeFoo()
+    return if (foo != null<caret>) {
+        foo.length
+    }
+}

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

@@ -1838,6 +1838,12 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("noElseBlockAsExpression.kt")
+            public void testNoElseBlockAsExpression() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/noElseBlockAsExpression.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("noNullInCondition.kt")
             public void testNoNullInCondition() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/branched/ifThenToSafeAccess/noNullInCondition.kt");