Merge f766827 into 8db4bef

morelinq · Jun 25, 2023 · ba5c8c5 · ba5c8c5
2 parents 8db4bef + f766827
commit ba5c8c5
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Showing 2 changed files with 16 additions and 3 deletions.
diff --git a/MoreLinq.Test/FillForwardTest.cs b/MoreLinq.Test/FillForwardTest.cs
@@ -83,5 +83,18 @@ select line.Trim() into line
                 new { Continent = "Africa", Country = "Kenya",   City = "Nairobi",    Value = 901 },
             }));
         }
+
+        /// <summary>
+        /// Exercises bug reported in <see
+        /// href="https://github.com/morelinq/MoreLINQ/issues/999">issue #999</see>.
+        /// </summary>
+
+        [Test]
+        public void FillForwardWithNullFiller()
+        {
+            var input = new int?[] { null, 1, null, 2, null, 3, null };
+            var result = input.FillForward(x => x is not null);
+            result.AssertSequenceEqual(Enumerable.Repeat((int?)null, input.Length));
+        }
     }
 }
diff --git a/MoreLinq/FillForward.cs b/MoreLinq/FillForward.cs
@@ -112,10 +112,10 @@ static IEnumerable<T> FillForwardImpl<T>(IEnumerable<T> source, Func<T, bool> pr
             {
                 if (predicate(item))
                 {
-                    yield return seed is (true, { } someSeed)
+                    yield return seed is (true, var theSeed)
                                ? fillSelector != null
-                                 ? fillSelector(item, someSeed)
-                                 : someSeed
+                                 ? fillSelector(item, theSeed)
+                                 : theSeed
                                : item;
                 }
                 else