Improve check for statements-only postfix templates

Before this change the check was quite complicated
because of cases like:
for (i in 1..9)
    foo(i)<caret>

It's not located in a block, but in the same time it's a stament.
So we had a tricky heuristics that if is parent is not a block, then
we should check if element isn't used as expression.

Of course this heuristics is wrong, e.g. for import/package nodes.

The solution is to reuse similar logic from BasicExpressionTypingVisitor.
it has been checked once that statement container is one of:
- KtBlockExpression
- KtContainerNodeForControlStructureBody
- KtWhenEntry

So there's no need to check anything else

 #KT-14986 Fixed
 #KT-14483 Fixed

compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiUtil.java

@@ -860,4 +860,14 @@ public class KtPsiUtil {
         }
         return deparenthesizedExpression;
     }
+
+    public static boolean isStatementContainer(@Nullable PsiElement container) {
+        return container instanceof KtBlockExpression ||
+               container instanceof KtContainerNodeForControlStructureBody ||
+               container instanceof KtWhenEntry;
+    }
+
+    public static boolean isStatement(@NotNull PsiElement element) {
+        return isStatementContainer(element.getParent());
+    }
 }

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/BasicExpressionTypingVisitor.java

@@ -1681,13 +1681,7 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
             parent = parent.getParent();
         }
 
-        return isParentForBlockLevelExpression(parent);
-    }
-
-    private static boolean isParentForBlockLevelExpression(@Nullable PsiElement parent) {
-        return parent instanceof KtBlockExpression ||
-               parent instanceof KtContainerNodeForControlStructureBody ||
-               parent instanceof KtWhenEntry;
+        return KtPsiUtil.isStatementContainer(parent);
     }
 
     @Override

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

@@ -34,7 +34,6 @@ import org.jetbrains.kotlin.psi.psiUtil.endOffset
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForReceiverOrThis
 import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsStatement
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.types.KotlinType
@@ -145,8 +144,11 @@ private class KtExpressionPostfixTemplateSelector(
         val bindingContext by lazy { element.analyze(BodyResolveMode.PARTIAL) }
 
         if (statementsOnly) {
-            val elementToCheck = element.getQualifiedExpressionForReceiverOrThis()
-            if (elementToCheck.parent !is KtBlockExpression && !elementToCheck.isUsedAsStatement(bindingContext)) return false
+            // We use getQualifiedExpressionForReceiverOrThis because when postfix completion is run on some statement like:
+            // foo().try<caret>
+            // `element` points to `foo()` call, while we need to select the whole statement with `try` selector
+            // to check if it's in a statement position
+            if (!KtPsiUtil.isStatement(element.getQualifiedExpressionForReceiverOrThis())) return false
         }
         if (checkCanBeUsedAsValue && !element.canBeUsedAsValue()) return false
 

idea/testData/codeInsight/postfix/tryInLocalClass.kt

@@ -0,0 +1,6 @@
+fun foo() {
+    class A {
+        // it's not a statement, while it has a block expression as an ancestor
+        val w = 1.try<caret>
+    }
+}

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

@@ -0,0 +1,6 @@
+fun foo() {
+    class A {
+        // it's not a statement, while it has a block expression as an ancestor
+        val w = 1.try   <caret>
+    }
+}

idea/testData/codeInsight/postfix/tryOnImportStatement.kt

@@ -0,0 +1 @@
+import qwe.try<caret>

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

@@ -0,0 +1 @@
+import qwe.try  <caret>

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

@@ -180,12 +180,24 @@ public class PostfixTemplateProviderTestGenerated extends AbstractPostfixTemplat
         doTest(fileName);
     }
 
+    @TestMetadata("tryInLocalClass.kt")
+    public void testTryInLocalClass() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/tryInLocalClass.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("tryOnFor.kt")
     public void testTryOnFor() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/tryOnFor.kt");
         doTest(fileName);
     }
 
+    @TestMetadata("tryOnImportStatement.kt")
+    public void testTryOnImportStatement() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/tryOnImportStatement.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("tryOnStatement.kt")
     public void testTryOnStatement() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/postfix/tryOnStatement.kt");