use remove branch strategy

Author: MarcoRossignoli

src/coverlet.core/Coverage.cs

@@ -183,19 +183,6 @@ private void CalculateCoverage()
                             int ordinal = int.Parse(info[3]);
                             var branch = document.Branches[(start, ordinal)];
                             branch.Hits += hits;
-
-                            // for MoveNext() compiler autogenerated method we need to patch false positive (IAsyncStateMachine for instance) 
-                            // the idea is force same hits on other branch
-                            if (CecilSymbolHelper.IsMoveNext(branch.Method))
-                            {
-                                foreach (var moveNextBranch in document.Branches)
-                                {
-                                    if (moveNextBranch.Value.Method == branch.Method && moveNextBranch.Value != branch)
-                                    {
-                                        moveNextBranch.Value.Hits += hits;
-                                    }
-                                }
-                            }
                         }
                         else
                         {
@@ -209,6 +196,31 @@ private void CalculateCoverage()
                     }
                 }
 
+                // for MoveNext() compiler autogenerated method we need to patch false positive (IAsyncStateMachine for instance) 
+                // we'll remove all MoveNext() not covered branch              
+                foreach (var document in result.Documents)
+                {
+                    List<KeyValuePair<(int, int), Branch>> branchesToRemove = new List<KeyValuePair<(int, int), Branch>>();
+                    foreach (var branch in document.Value.Branches)
+                    {
+                        //if one branch is covered we search the other one only if it's not covered
+                        if (CecilSymbolHelper.IsMoveNext(branch.Value.Method) && branch.Value.Hits > 0)
+                        {
+                            foreach (var moveNextBranch in document.Value.Branches)
+                            {
+                                if (moveNextBranch.Value.Method == branch.Value.Method && moveNextBranch.Value != branch.Value && moveNextBranch.Value.Hits == 0)
+                                {
+                                    branchesToRemove.Add(moveNextBranch);
+                                }
+                            }
+                        }
+                    }
+                    foreach (var branchToRemove in branchesToRemove)
+                    {
+                        document.Value.Branches.Remove(branchToRemove.Key);
+                    }
+                }
+
                 InstrumentationHelper.DeleteHitsFile(result.HitsFilePath);
             }
         }