IDEA-131710 Unclear behavior of smart step into method after conditional operator - cleanup after review

java/debugger/impl/src/com/intellij/debugger/actions/SmartStepTarget.java

@@ -50,6 +50,7 @@ public abstract class SmartStepTarget {
     return myNeedBreakpointRequest;
   }
 
+  @Nullable
   public Range<Integer> getCallingExpressionLines() {
     return myExpressionLines;
   }

java/debugger/impl/src/com/intellij/debugger/engine/BasicStepMethodFilter.java

@@ -75,6 +75,7 @@ public class BasicStepMethodFilter implements NamedMethodFilter {
     return false;
   }
 
+  @Nullable
   @Override
   public Range<Integer> getCallingExpressionLines() {
     return myCallingExpressionLines;

java/debugger/impl/src/com/intellij/debugger/engine/LambdaMethodFilter.java

@@ -82,6 +82,7 @@ public class LambdaMethodFilter implements BreakpointStepMethodFilter{
     return method.name().startsWith(LAMBDA_METHOD_PREFIX) && (!vm.canGetSyntheticAttribute() || method.isSynthetic());
   }
 
+  @Nullable
   @Override
   public Range<Integer> getCallingExpressionLines() {
     return myCallingExpressionLines;

java/debugger/impl/src/com/intellij/debugger/engine/MethodFilter.java

@@ -18,8 +18,9 @@ package com.intellij.debugger.engine;
 import com.intellij.debugger.engine.evaluation.EvaluateException;
 import com.intellij.util.Range;
 import com.sun.jdi.Location;
+import org.jetbrains.annotations.Nullable;
 
 public interface MethodFilter {
   boolean locationMatches(DebugProcessImpl process, Location location) throws EvaluateException;
-  Range<Integer> getCallingExpressionLines();
+  @Nullable Range<Integer> getCallingExpressionLines();
 }

java/debugger/impl/src/com/intellij/debugger/engine/RequestHint.java

@@ -35,6 +35,7 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.Computable;
 import com.intellij.psi.PsiMethod;
 import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.Range;
 import com.sun.jdi.Location;
 import com.sun.jdi.Method;
 import com.sun.jdi.VMDisconnectedException;
@@ -142,8 +143,8 @@ public class RequestHint {
       return myPosition.getLine() == locationPosition.getLine();
     }
     else {
-      return locationPosition.getLine() >= myMethodFilter.getCallingExpressionLines().getFrom() &&
-             locationPosition.getLine() <= myMethodFilter.getCallingExpressionLines().getTo();
+      Range<Integer> exprLines = myMethodFilter.getCallingExpressionLines();
+      return exprLines != null && locationPosition.getLine() >= exprLines.getFrom() && locationPosition.getLine() <= exprLines.getTo();
     }
   }