diff --git a/Tests/TaggedNodeCorpusRoundTripTests.swift b/Tests/TaggedNodeCorpusRoundTripTests.swift
index 0235e63..0e34e18 100644
--- a/Tests/TaggedNodeCorpusRoundTripTests.swift
+++ b/Tests/TaggedNodeCorpusRoundTripTests.swift
@@ -19,25 +19,22 @@ struct TaggedNodeCorpusRoundTripTests {
         ))
         var accepted = 0
         var rejected = 0
-        // `URL.lastPathComponent` is `String` on Darwin's Foundation but `String?` on this
-        // toolchain's swift-corelibs-foundation. Every attempt to derive a `[URL]` THROUGH a
-        // `map`/`sorted` chain touching `.lastPathComponent` -- an inline cast, a named helper, a
-        // tuple-and-keypath precompute -- came back from the Linux relay with `url` re-inferred as
-        // `NSURL` somewhere downstream, breaking `String(contentsOf:encoding:)`. Sorting the plain
-        // `Int` INDICES instead keeps every `.sorted(by:)`/`.map` in this file entirely divorced
-        // from any URL-typed value; `urls[index]` below is the one and only place a `URL` from the
-        // original, never-transformed array is touched, so its type can never drift.
+        // Two independent Darwin/Linux Foundation divergences on this toolchain, both worked
+        // around the same way (an explicit `as String?` coercion so both platforms produce a
+        // uniform Optional before `?? ""`, since one side's non-optional String cannot itself
+        // take `??`): (1) `URL.lastPathComponent` is `String` on Darwin, `String?` here, used for
+        // the sort key and the diagnostic labels below. (2) `String(contentsOf: url, encoding:)`
+        // itself hits a documented Linux-only NSURL/URL bridging bug in
+        // swift-corelibs-foundation (swiftlang/swift-corelibs-foundation#3707), independent of
+        // how `url` is obtained -- `contentsOfFile:` (a `String`-path overload with no such
+        // bridging ambiguity) sidesteps it, which needs `URL.path`'s own String/String? split
+        // handled the same way as `lastPathComponent`.
         let names = urls.map { ($0.lastPathComponent as String?) ?? "" }
         let order = names.indices.sorted { names[$0] < names[$1] }
         for index in order {
             let url = urls[index]
-            // `String(contentsOf: url, encoding:)` itself hit the same NSURL/URL confusion on
-            // this toolchain regardless of how `url` was obtained (a bare `for url in urls` with
-            // no sort at all reproduces it too). `contentsOfFile:` takes a `String` path -- a
-            // type this toolchain's Foundation does not have two conflicting URL/NSURL overloads
-            // for -- sidestepping the ambiguity at its actual point of failure instead of
-            // upstream of it.
-            let source = try String(contentsOfFile: url.path, encoding: .utf8)
+            let path = (url.path as String?) ?? ""
+            let source = try String(contentsOfFile: path, encoding: .utf8)
             let parsed: PureYAML.Tagged.Node
             do {
                 parsed = try PureYAML.parseTagged(source)