@@ -22,13 +22,16 @@ partial class Program
     internal static StringComparer PathComparer =>
         OperatingSystem.IsWindows() ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal;
 
-    static bool SourceExists(string path) =>
-        SourceOverlay?.ContainsKey(Path.GetFullPath(path)) == true || File.Exists(path);
-
-    static string ReadSource(string path) =>
-        SourceOverlay is not null && SourceOverlay.TryGetValue(Path.GetFullPath(path), out var text)
-            ? text
-            : File.ReadAllText(path);
+    /// <summary>The overlaid text of <paramref name="path"/>, when an overlay holds it. No
+    /// filesystem access: the disk read stays at its one site in the parse loop.</summary>
+    static bool TryOverlay(string path, out string text)
+    {
+        text = "";
+        if (SourceOverlay is null || !SourceOverlay.TryGetValue(Path.GetFullPath(path), out var held))
+            return false;
+        text = held;
+        return true;
+    }
 }
 
 namespace OwnSharp.Extractor
 
@@ -5703,23 +5703,26 @@ static bool IsPublicCtor(SyntaxTokenList modifiers)
     // Defensive: an explicit input that is not a readable file (a directory
     // passed by mistake, a deleted path) is skipped with a note, never an
     // unhandled exception that aborts the whole scan.
-    if (!SourceExists(path))
+    // OX-02: an IDE's unsaved buffer for this path is read INSTEAD of the file
+    // (InProcessExtractor). The CLI never has an overlay, so for it this is the disk path
+    // below, unchanged.
+    if (!TryOverlay(path, out var text))
     {
-        Console.Error.WriteLine($"ownsharp-extract: skipping (not a file): {path}");
-        continue;
-    }
-    string text;
-    try
-    {
-        // OX-02: an IDE's unsaved buffer for this path wins over the file on disk
-        // (InProcessExtractor); with no overlay — the CLI — this is File.ReadAllText.
-        text = ReadSource(path);
-    }
-    catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
-    {
-        // A locked/unreadable file is skipped with a note, not an abort.
-        Console.Error.WriteLine($"ownsharp-extract: skipping unreadable file: {path} ({ex.Message})");
-        continue;
+        if (!File.Exists(path))
+        {
+            Console.Error.WriteLine($"ownsharp-extract: skipping (not a file): {path}");
+            continue;
+        }
+        try
+        {
+            text = File.ReadAllText(path);
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+        {
+            // A locked/unreadable file is skipped with a note, not an abort.
+            Console.Error.WriteLine($"ownsharp-extract: skipping unreadable file: {path} ({ex.Message})");
+            continue;
+        }
     }
     parsed.Add((Rel(path), CSharpSyntaxTree.ParseText(text, path: path)));
     if (path.EndsWith(".xaml.cs", StringComparison.OrdinalIgnoreCase))
 
@@ -72,9 +72,8 @@
     (
         "M6",
         os.path.join(EXTRACTOR, "InProcess.cs"),
-        "SourceOverlay is not null && "
-        "SourceOverlay.TryGetValue(Path.GetFullPath(path), out var text)",
-        "false && SourceOverlay!.TryGetValue(Path.GetFullPath(path), out var text)",
+        "if (SourceOverlay is null || !SourceOverlay.TryGetValue(",
+        "if (true || !SourceOverlay!.TryGetValue(",
         "gate",
         ["K2-unsaved-own002"],
     ),
 
@@ -143,23 +143,25 @@ def main() -> int:
                 elif _read(outs[i]) != _read(cli_out[i]):
                     fails.append(f"{label} {name}: facts differ from the command line's")
 
-        # E3/E4: OrderBackend, the endpoint file overlaid
-        project = "samples/OrderBackend/OrderBackend"
-        target = os.path.join(ROOT, project, "OrderEndpoints.cs")
+        # E3/E4: the samples directory, one file overlaid. Self-contained on purpose: a run
+        # whose facts depend on a built bin/ (OrderBackend's EF types) would refuse on a
+        # clean checkout and compare no facts with no facts.
+        project = SAMPLES
+        target = os.path.join(ROOT, project, "FlowLocalsSample.cs")
         with open(target, encoding="utf-8") as f:
             original = f.read()
         same = os.path.join(tmp, "same.cs")
         with open(same, "w", encoding="utf-8", newline="") as f:
             f.write(original)
         # a non-escaping disposable local: the flow pass emits a function for it
         changed_text = original + (
-            "\nnamespace OrderBackend { static class OverlayProbe { static void M() "
-            "{ var s = new System.IO.MemoryStream(); s.WriteByte(1); } } }\n"
+            "\nstatic class OverlayProbe { static void M() "
+            "{ var s = new System.IO.MemoryStream(); s.WriteByte(1); } }\n"
         )
         changed = os.path.join(tmp, "changed.cs")
         with open(changed, "w", encoding="utf-8", newline="") as f:
             f.write(changed_text)
-        args = [f"{project}/OrderBackend.csproj", "--flow-locals"]
+        args = [project, "--flow-locals"]
         base_out = os.path.join(tmp, "e3-base.json")
         _cli(dll, args, base_out)
         e3 = os.path.join(tmp, "e3.json")
@@ -177,17 +179,18 @@ def main() -> int:
             fails.append("E3: an overlay equal to the disk changed the facts")
         # the same change made on disk, in a copy of the tree, run by the command line
         copy = os.path.join(tmp, "tree")
-        # bin/ included: a .csproj input auto-references the project's built output
         shutil.copytree(os.path.join(ROOT, project), os.path.join(copy, project))
         with open(
-            os.path.join(copy, project, "OrderEndpoints.cs"), "w", encoding="utf-8", newline=""
+            os.path.join(copy, project, "FlowLocalsSample.cs"), "w", encoding="utf-8", newline=""
         ) as f:
             f.write(changed_text)
         disk_out = os.path.join(tmp, "e4-disk.json")
         _cli(dll, args, disk_out, cwd=copy)
         checks += 1
         e4_bytes = _read(e4)
-        if e4_bytes is None or e4_bytes == _read(base_out):
+        if _read(base_out) is None:
+            fails.append("E4: the unchanged samples produced no facts; nothing was compared")
+        elif e4_bytes is None or e4_bytes == _read(base_out):
             fails.append(
                 "E4: an overlay that differs from the disk did not change the facts "
                 "(the disk was read instead of the buffer)"