Refactoring of IfThen: ToDoubleBang / ToElvis / ToSafeAccess

Some common actions were extracted to IfThenUtils.kt
Use consistent logic in all three intentions
Also fixes potential PSI consistency problems in conversions dot->safe calls

idea/testData/intentions/branched/ifThenToSafeAccess/inspectionData/expected.xml

@@ -111,4 +111,28 @@
     <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
     <description>Replace 'if' expression with safe access expression</description>
   </problem>
+  <problem>
+    <file>nullCheckWithSelectorCallChain.kt</file>
+    <line>5</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/nullCheckWithSelectorCallChain.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
+    <description>Replace 'if' expression with safe access expression</description>
+  </problem>
+  <problem>
+    <file>isCheckWithSelectorChain.kt</file>
+    <line>4</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/isCheckWithSelectorChain.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
+    <description>Replace 'if' expression with safe access expression</description>
+  </problem>
+  <problem>
+    <file>isCheckSimple.kt</file>
+    <line>4</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/isCheckSimple.kt" />
+    <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">If-Then foldable to '?.'</problem_class>
+    <description>Replace 'if' expression with safe access expression</description>
+  </problem>
 </problems>

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

@@ -0,0 +1,5 @@
+class My(val x: Int)
+
+fun foo(arg: Any?): My? {
+    return if (<caret>arg is My) arg else null
+}

idea/testData/intentions/branched/ifThenToSafeAccess/isCheckSimple.kt.after

@@ -0,0 +1,5 @@
+class My(val x: Int)
+
+fun foo(arg: Any?): My? {
+    return arg as? My
+}

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

@@ -0,0 +1,5 @@
+class My(val x: Int)
+
+fun foo(arg: Any?): Int? {
+    return if (<caret>arg is My) arg.x.hashCode() else null
+}

idea/testData/intentions/branched/ifThenToSafeAccess/isCheckWithSelectorChain.kt.after

@@ -0,0 +1,5 @@
+class My(val x: Int)
+
+fun foo(arg: Any?): Int? {
+    return (arg as? My)?.x?.hashCode()
+}

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

@@ -0,0 +1,5 @@
+// IS_APPLICABLE: false
+
+fun foo(arg: Any?): Any? {
+    return if (<caret>arg != null) arg else null
+}

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

@@ -0,0 +1,9 @@
+// WITH_RUNTIME
+
+val nullableString: String? = "abc"
+
+val foo = if (<caret>nullableString != null) {
+    nullableString.toUpperCase().toLowerCase()
+} else {
+    null
+}

idea/testData/intentions/branched/ifThenToSafeAccess/nullCheckWithSelectorCallChain.kt.after

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+val nullableString: String? = "abc"
+
+val foo = nullableString?.toUpperCase()?.toLowerCase()