some validity assertions (EA-26543)

java/java-impl/src/com/intellij/codeInsight/generation/surroundWith/JavaWithCastSurrounder.java

@@ -40,6 +40,7 @@ class JavaWithCastSurrounder extends JavaExpressionSurrounder {
   }
 
   public TextRange surroundExpression(final Project project, final Editor editor, PsiExpression expr) throws IncorrectOperationException {
+    assert expr.isValid();
     PsiType[] types = GuessManager.getInstance(project).guessTypeToCast(expr);
     final Template template = generateTemplate(project, expr.getText(), types);
     TextRange range = expr.getTextRange();

java/java-impl/src/com/intellij/codeInsight/guess/impl/GuessManagerImpl.java

@@ -162,6 +162,7 @@ public class GuessManagerImpl extends GuessManager {
   }
 
   private static Map<PsiExpression, PsiType> getAllTypeCasts(PsiExpression forPlace) {
+    assert forPlace.isValid();
     final int start = forPlace.getTextRange().getStartOffset();
     final Map<PsiExpression, PsiType> allCasts = new THashMap<PsiExpression, PsiType>(ExpressionTypeMemoryState.EXPRESSION_HASHING_STRATEGY);
     getTopmostBlock(forPlace).accept(new JavaRecursiveElementWalkingVisitor() {
@@ -198,6 +199,7 @@ public class GuessManagerImpl extends GuessManager {
   }
 
   private static PsiElement getTopmostBlock(PsiElement scope) {
+    assert scope.isValid();
     PsiElement lastScope = scope;
     while (true) {
       final PsiCodeBlock lastCodeBlock = PsiTreeUtil.getParentOfType(lastScope, PsiCodeBlock.class, true);