Fix for KT-6202: Redundant and wrong linenumber after if/else condition

#KT-6202 Fixed

compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -403,7 +403,8 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
 
         gen(elseExpression, asmType);
 
-        markLineNumber(expression);
+        markExpressionLineNumber(expression, isStatement);
+
         v.mark(end);
 
         return StackValue.onStack(asmType);
@@ -1216,10 +1217,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
             Label end = new Label();
             v.goTo(end);
 
-            markLineNumber(ifExpression);
             v.mark(elseLabel);
             StackValue.putUnitInstance(v);
 
+            markLineNumber(ifExpression);
             v.mark(end);
             return StackValue.onStack(targetType);
         }
@@ -1546,6 +1547,12 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
         });
     }
 
+    public void markExpressionLineNumber(@NotNull JetElement element, boolean isStatement) {
+        if (!isStatement) {
+            markLineNumber(element);
+        }
+    }
+
     public void markLineNumber(@NotNull JetElement statement) {
         Document document = statement.getContainingFile().getViewProvider().getDocument();
         if (document != null) {
@@ -3609,7 +3616,7 @@ The "returned" value of try expression with no finally is either the last expres
             generateExceptionTable(defaultCatchStart, defaultCatchRegions, null);
         }
 
-        markLineNumber(expression);
+        markExpressionLineNumber(expression, isStatement);
         v.mark(end);
 
         if (!isStatement) {
@@ -3822,7 +3829,7 @@ The "returned" value of try expression with no finally is either the last expres
             }
         }
 
-        markLineNumber(expression);
+        markExpressionLineNumber(expression, isStatement);
         v.mark(end);
 
         myFrameMap.leaveTemp(subjectType);

compiler/backend/src/org/jetbrains/jet/codegen/when/SwitchCodegen.java

@@ -86,7 +86,7 @@ abstract public class SwitchCodegen {
             codegen.putUnitInstanceOntoStackForNonExhaustiveWhen(expression);
         }
 
-        codegen.markLineNumber(expression);
+        codegen.markExpressionLineNumber(expression, isStatement);
         v.mark(endLabel);
     }