diff --git a/config/identical-files.json b/config/identical-files.json
index d14052c12d8..89a1e6fc363 100644
--- a/config/identical-files.json
+++ b/config/identical-files.json
@@ -355,5 +355,9 @@
   "Python model summaries test extension": [
     "python/ql/test/library-tests/dataflow/model-summaries/InlineTaintTest.ext.yml",
     "python/ql/test/library-tests/dataflow/model-summaries/NormalDataflowTest.ext.yml"
+  ],
+  "Diagnostics.qll": [
+    "ruby/ql/lib/codeql/ruby/Diagnostics.qll",
+    "rust/ql/lib/codeql/rust/Diagnostics.qll"
   ]
 }
diff --git a/rust/ql/lib/codeql/rust/Diagnostics.qll b/rust/ql/lib/codeql/rust/Diagnostics.qll
new file mode 100644
index 00000000000..faf7b8420a0
--- /dev/null
+++ b/rust/ql/lib/codeql/rust/Diagnostics.qll
@@ -0,0 +1,52 @@
+private import codeql.Locations
+
+/** A diagnostic emitted during extraction, such as a parse error */
+class Diagnostic extends @diagnostic {
+  int severity;
+  string tag;
+  string message;
+  string fullMessage;
+  Location location;
+
+  Diagnostic() { diagnostics(this, severity, tag, message, fullMessage, location) }
+
+  /**
+   * Gets the numerical severity level associated with this diagnostic.
+   */
+  int getSeverity() { result = severity }
+
+  /** Gets a string representation of the severity of this diagnostic. */
+  string getSeverityText() {
+    severity = 10 and result = "Debug"
+    or
+    severity = 20 and result = "Info"
+    or
+    severity = 30 and result = "Warning"
+    or
+    severity = 40 and result = "Error"
+  }
+
+  /** Gets the error code associated with this diagnostic, e.g. parse_error. */
+  string getTag() { result = tag }
+
+  /**
+   * Gets the error message text associated with this diagnostic.
+   */
+  string getMessage() { result = message }
+
+  /**
+   * Gets the full error message text associated with this diagnostic.
+   */
+  string getFullMessage() { result = fullMessage }
+
+  /** Gets the source location of this diagnostic. */
+  Location getLocation() { result = location }
+
+  /** Gets a textual representation of this diagnostic. */
+  string toString() { result = this.getMessage() }
+}
+
+/** A diagnostic relating to a particular error in extracting a file. */
+class ExtractionError extends Diagnostic {
+  ExtractionError() { this.getTag() = "parse_error" }
+}