diff --git a/runtime/src/main/java/dev/ionfusion/runtime/_private/util/IonCatalogLoader.java b/runtime/src/main/java/dev/ionfusion/runtime/_private/util/IonCatalogLoader.java
index be5829b6..e893c9d5 100644
--- a/runtime/src/main/java/dev/ionfusion/runtime/_private/util/IonCatalogLoader.java
+++ b/runtime/src/main/java/dev/ionfusion/runtime/_private/util/IonCatalogLoader.java
@@ -13,6 +13,8 @@
 import com.amazon.ion.system.IonReaderBuilder;
 import com.amazon.ion.system.IonSystemBuilder;
 import com.amazon.ion.system.SimpleCatalog;
+import dev.ionfusion.runtime.base.ResourceDescriptor;
+import dev.ionfusion.runtime.base.ResourcePosition;
 import dev.ionfusion.runtime.base.SourceLocation;
 import dev.ionfusion.runtime.base.SourceName;
 import java.io.File;
@@ -58,15 +60,15 @@ private static boolean hasSharedSymtabAnnotation(IonReader reader)
     }
 
 
-    private String prefix(SourceLocation loc)
+    private String prefix(ResourcePosition loc)
     {
         return "Error reading symbol table at " + loc.display() + ":\n";
     }
 
 
-    void loadSymtab(SourceName name, IonReader reader)
+    void loadSymtab(ResourceDescriptor rsrc, IonReader reader)
     {
-        SourceLocation loc = SourceLocation.forCurrentSpan(reader, name);
+        ResourcePosition loc = SourceLocation.forCurrentSpan(reader, rsrc);
 
         if (reader.getType() != IonType.STRUCT)
         {
@@ -96,7 +98,7 @@ void loadSymtab(SourceName name, IonReader reader)
         catch (IonException e)
         {
             // We use the location of the symtab as a whole, because when things
-            // fail the IonReader's cursor is usually in between values and thus
+            // fail, the IonReader's cursor is usually in between values and thus
             // there's no current span.
             String message = prefix(loc) + e.getMessage();
             throw new IonException(message, e);
@@ -107,7 +109,7 @@ void loadSymtab(SourceName name, IonReader reader)
     private void loadFile(File file)
         throws IOException
     {
-        SourceName name = SourceName.forFile(file.getPath());
+        ResourceDescriptor name = SourceName.forFile(file.getPath());
 
         try (FileInputStream stream = new FileInputStream(file);
              IonReader reader = myReaderBuilder.build(stream))
diff --git a/runtime/src/main/java/dev/ionfusion/runtime/base/ResourcePosition.java b/runtime/src/main/java/dev/ionfusion/runtime/base/ResourcePosition.java
index 01d46125..f03d1f5f 100644
--- a/runtime/src/main/java/dev/ionfusion/runtime/base/ResourcePosition.java
+++ b/runtime/src/main/java/dev/ionfusion/runtime/base/ResourcePosition.java
@@ -4,6 +4,7 @@
 package dev.ionfusion.runtime.base;
 
 import java.io.IOException;
+import java.io.UncheckedIOException;
 
 /**
  * A specific location within some resource.
@@ -66,4 +67,26 @@ default ResourceIdentifier getResourceId()
      */
     void display(Appendable out)
         throws IOException;
+
+
+    /**
+     * Displays this position in a human-readable form, in terms of line, column, and
+     * resource.  Additional semantic context may also be included.
+     *
+     * @return not null.
+     */
+    default String display()
+    {
+        StringBuilder out = new StringBuilder();
+        try
+        {
+            display(out);
+        }
+        catch (IOException e)
+        {
+            // StringBuilder shouldn't throw this, but let's be safe.
+            throw new UncheckedIOException(e);
+        }
+        return out.toString();
+    }
 }