Span::resolved_at and Span::located_at to combine behavior of two spans
diff --git a/src/stable.rs b/src/stable.rs
index b5820b1..0a439ed 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -334,6 +334,17 @@
         Span::call_site()
     }
 
+    pub fn resolved_at(&self, _other: Span) -> Span {
+        // Stable spans consist only of line/column information, so
+        // `resolved_at` and `located_at` only select which span the
+        // caller wants line/column information from.
+        *self
+    }
+
+    pub fn located_at(&self, other: Span) -> Span {
+        other
+    }
+
     #[cfg(procmacro2_semver_exempt)]
     pub fn source_file(&self) -> SourceFile {
         CODEMAP.with(|cm| {