diff --git a/changelog.d/unreleased/4917.internal.md b/changelog.d/unreleased/4917.internal.md
new file mode 100644
index 000000000..49d2adae5
--- /dev/null
+++ b/changelog.d/unreleased/4917.internal.md
@@ -0,0 +1,18 @@
+---
+category: internal
+issues:
+  - 4917
+affected:
+  - src/CodeIndex/Cli/DiffCommandRunner.cs
+  - src/CodeIndex/Indexer/References/Languages/ShaderReferenceExtractor.cs
+  - src/CodeIndex/Indexer/Symbols/SymbolExtractor.ExtractCore.cs
+  - src/CodeIndex/Lsp/LspServer.PositionResolution.cs
+---
+
+## English
+
+- **Removed four superseded internal helpers (#4917)** — deleted unused diff string-row equality, shader quoted-include, Prolog clause-terminator, and LSP position-preference helpers after confirming their active call paths use the more complete ordered-diff, general shader-include, top-level Prolog terminator, and position-aware definition-resolution implementations.
+
+## 日本語
+
+- **置換済みの内部 helper 4 件を削除しました (#4917)** — 現在の call path が、より完全な ordered diff、shader include の共通処理、Prolog の top-level terminator 判定、position-aware な definition resolution を使用していることを確認し、未使用となっていた diff の string-row equality、shader の quoted-include、Prolog の clause-terminator、LSP の position-preference helper を削除しました。
diff --git a/src/CodeIndex/Cli/DiffCommandRunner.cs b/src/CodeIndex/Cli/DiffCommandRunner.cs
index 0341bd4d8..fe7e2ecd4 100644
--- a/src/CodeIndex/Cli/DiffCommandRunner.cs
+++ b/src/CodeIndex/Cli/DiffCommandRunner.cs
@@ -1148,31 +1148,6 @@ private static bool RowsEqual(SqliteConnection leftConnection, SqliteConnection
         return leftHasValue == rightHasValue;
     }
 
-    private static bool StringRowsEqual(SqliteConnection leftConnection, SqliteConnection rightConnection, string sql, CancellationToken cancellationToken)
-    {
-        using var leftCommand = leftConnection.CreateCommand();
-        leftCommand.CommandText = sql;
-        using var rightCommand = rightConnection.CreateCommand();
-        rightCommand.CommandText = sql;
-        using var leftReader = leftCommand.ExecuteReader();
-        using var rightReader = rightCommand.ExecuteReader();
-
-        var leftRowsRead = 0;
-        var rightRowsRead = 0;
-        var leftHasValue = TryReadString(leftReader, out var leftValue, ref leftRowsRead, "left", cancellationToken);
-        var rightHasValue = TryReadString(rightReader, out var rightValue, ref rightRowsRead, "right", cancellationToken);
-        while (leftHasValue && rightHasValue)
-        {
-            cancellationToken.ThrowIfCancellationRequested();
-            if (!string.Equals(leftValue, rightValue, StringComparison.Ordinal))
-                return false;
-            leftHasValue = TryReadString(leftReader, out leftValue, ref leftRowsRead, "left", cancellationToken);
-            rightHasValue = TryReadString(rightReader, out rightValue, ref rightRowsRead, "right", cancellationToken);
-        }
-
-        return leftHasValue == rightHasValue;
-    }
-
     private static bool TryReadRow(SqliteDataReader reader, out DiffRow value, ref int rowsRead, string side, CancellationToken cancellationToken)
     {
         cancellationToken.ThrowIfCancellationRequested();
diff --git a/src/CodeIndex/Indexer/References/Languages/ShaderReferenceExtractor.cs b/src/CodeIndex/Indexer/References/Languages/ShaderReferenceExtractor.cs
index 3e1c860c9..5717f40fa 100644
--- a/src/CodeIndex/Indexer/References/Languages/ShaderReferenceExtractor.cs
+++ b/src/CodeIndex/Indexer/References/Languages/ShaderReferenceExtractor.cs
@@ -22,9 +22,6 @@ internal static class ShaderReferenceExtractor
     private static readonly Regex IncludeDirectiveRegex = new(
         @"^\s*#\s*include\b",
         SharedRegexOptions);
-    private static readonly Regex QuotedIncludeRegex = new(
-        @"^\s*#\s*include\s*""(?<path>[^""\r\n]+)""",
-        SharedRegexOptions);
     private static readonly Regex CudaKernelLaunchRegex = new(
         @"(?<![\w:])(?<name>(?:[A-Za-z_]\w*::)*[A-Za-z_]\w*)(?:\s*<[^<>\r\n]{1,512}>)?\s*<<<",
         SharedRegexOptions);
diff --git a/src/CodeIndex/Indexer/Symbols/SymbolExtractor.ExtractCore.cs b/src/CodeIndex/Indexer/Symbols/SymbolExtractor.ExtractCore.cs
index 0c9bd329a..39dd03b38 100644
--- a/src/CodeIndex/Indexer/Symbols/SymbolExtractor.ExtractCore.cs
+++ b/src/CodeIndex/Indexer/Symbols/SymbolExtractor.ExtractCore.cs
@@ -1571,23 +1571,6 @@ private static void AddPrologMultilineHeadSymbols(
         }
     }
 
-    private static bool HasPrologClauseTerminator(string line)
-    {
-        for (var column = 0; column < line.Length; column++)
-        {
-            if (line[column] is '\'' or '"')
-            {
-                column = SkipPrologQuotedTerm(line, column, line[column]) - 1;
-                continue;
-            }
-
-            if (DynamicDeclarativeReferenceExtractor.IsPrologClauseTerminator(line, column))
-                return true;
-        }
-
-        return false;
-    }
-
     private static int SkipPrologQuotedTerm(string line, int startColumn, char delimiter)
     {
         for (var column = startColumn + 1; column < line.Length; column++)
diff --git a/src/CodeIndex/Lsp/LspServer.PositionResolution.cs b/src/CodeIndex/Lsp/LspServer.PositionResolution.cs
index c689eef6e..bf5055ce1 100644
--- a/src/CodeIndex/Lsp/LspServer.PositionResolution.cs
+++ b/src/CodeIndex/Lsp/LspServer.PositionResolution.cs
@@ -268,14 +268,6 @@ private static bool TryCountCommaSeparatedItems(
         return false;
     }
 
-    private List<DefinitionResult> PreferDefinitionAtPosition(
-        List<DefinitionResult> definitions,
-        PositionTokenContext context)
-    {
-        var positioned = FindDefinitionsAtPosition(definitions, context);
-        return positioned.Count > 0 ? positioned : definitions;
-    }
-
     private List<DefinitionResult> FindDefinitionsAtPosition(
         List<DefinitionResult> definitions,
         PositionTokenContext context)