Allow if/when/try postfix templates in expression position

#KT-14078 Fixed

idea/src/org/jetbrains/kotlin/idea/codeInsight/postfix/surrounderBasedPostfixTemplates.kt

@@ -29,14 +29,14 @@ import org.jetbrains.kotlin.types.typeUtil.isBoolean
 
 internal object KtIfExpressionPostfixTemplate : SurroundPostfixTemplateBase(
         "if", "if (expr)",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true) { it.isBoolean() }
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false) { it.isBoolean() }
 ) {
     override fun getSurrounder() = KotlinWithIfExpressionSurrounder(withElse = false)
 }
 
 internal object KtElseExpressionPostfixTemplate : SurroundPostfixTemplateBase(
         "else", "if (!expr)",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true) { it.isBoolean() }
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false) { it.isBoolean() }
 ) {
     override fun getSurrounder() = KotlinWithIfExpressionSurrounder(withElse = false)
     override fun getWrappedExpression(expression: PsiElement?) = (expression as KtExpression).negate()
@@ -44,7 +44,7 @@ internal object KtElseExpressionPostfixTemplate : SurroundPostfixTemplateBase(
 
 internal class KtNotNullPostfixTemplate(val name: String) : SurroundPostfixTemplateBase(
         name, "if (expr != null)",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true, predicate = TypeUtils::isNullableType)
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false, predicate = TypeUtils::isNullableType)
 ) {
     override fun getSurrounder() = KotlinWithIfExpressionSurrounder(withElse = false)
     override fun getTail() = "!= null"
@@ -52,7 +52,7 @@ internal class KtNotNullPostfixTemplate(val name: String) : SurroundPostfixTempl
 
 internal object KtIsNullPostfixTemplate : SurroundPostfixTemplateBase(
         "null", "if (expr == null)",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true, predicate = TypeUtils::isNullableType)
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false, predicate = TypeUtils::isNullableType)
 ) {
     override fun getSurrounder() = KotlinWithIfExpressionSurrounder(withElse = false)
     override fun getTail() = "== null"
@@ -60,14 +60,14 @@ internal object KtIsNullPostfixTemplate : SurroundPostfixTemplateBase(
 
 internal object KtWhenExpressionPostfixTemplate : SurroundPostfixTemplateBase(
         "when", "when (expr)",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true)
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false)
 ) {
     override fun getSurrounder() = KotlinWhenSurrounder()
 }
 
 internal object KtTryPostfixTemplate : SurroundPostfixTemplateBase(
         "try", "try { code } catch (e: Exception) { }",
-        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = true)
+        KtPostfixTemplatePsiInfo, createExpressionSelector(statementsOnly = false)
 ) {
     override fun getSurrounder() = KotlinTryCatchSurrounder()
 }

idea/testData/codeInsight/postfix/whenExpression.kt

@@ -0,0 +1,3 @@
+fun foo(x: String) {
+    val y = x.when<caret>
+}

idea/testData/codeInsight/postfix/whenExpression.kt.after

@@ -0,0 +1,8 @@
+fun foo(x: String) {
+    val y = when (x) {
+         -> {
+        }
+        else -> {
+        }
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/postfix/PostfixTemplateProviderTestGenerated.java

@@ -161,6 +161,12 @@ public class PostfixTemplateProviderTestGenerated extends AbstractPostfixTemplat
         doTest(fileName);
     }
 
+    @TestMetadata("whenExpression.kt")
+    public void testWhenExpression() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/whenExpression.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("while.kt")
     public void testWhile() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/while.kt");