From 6c487cffdbd3fcbc4a08acf6ddb71af735b75d06 Mon Sep 17 00:00:00 2001
From: Mick Cooney <mcooney@describedata.com>
Date: Fri, 16 Oct 2026 17:11:11 +0100
Subject: [PATCH] fix(r): bind roxygen @param tags to formals written in
 backticks

A formal written `data` in backticks never matched the tag @param data, so
its documented type was dropped. Look the tag up by the symbol.
---
 gitnexus/src/core/ingestion/type-extractors/r.ts |  4 +++-
 gitnexus/test/unit/type-env-r.test.ts            | 13 +++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/gitnexus/src/core/ingestion/type-extractors/r.ts b/gitnexus/src/core/ingestion/type-extractors/r.ts
index b1a815f22..f5e159b8c 100644
--- a/gitnexus/src/core/ingestion/type-extractors/r.ts
+++ b/gitnexus/src/core/ingestion/type-extractors/r.ts
@@ -7,6 +7,7 @@ import type {
 } from './types.js';
 import type { SyntaxNode } from '../utils/ast-helpers.js';
 import { getRClassNameArgument } from '../field-extractors/r.js';
+import { rBareName } from '../languages/r/bare-name.js';
 
 /**
  * R type extractor — roxygen2 annotation parsing.
@@ -205,7 +206,8 @@ const extractParameter: ParameterExtractor = (node: SyntaxNode, env: Map<string,
   const rhs = assignment.childForFieldName('rhs');
   if (rhs?.startIndex !== fn.startIndex || rhs.endIndex !== fn.endIndex) return;
 
-  const typeName = collectRoxygenParams(assignment).get(name.text);
+  // The tag names the symbol (`@param x`); a formal written `x` in backticks is the same one.
+  const typeName = collectRoxygenParams(assignment).get(rBareName(name.text));
   if (typeName !== undefined) env.set(name.text, typeName);
 };
 
diff --git a/gitnexus/test/unit/type-env-r.test.ts b/gitnexus/test/unit/type-env-r.test.ts
index 251a4696c..53ed7020e 100644
--- a/gitnexus/test/unit/type-env-r.test.ts
+++ b/gitnexus/test/unit/type-env-r.test.ts
@@ -75,6 +75,19 @@ AddOutlierStatuses <- function(data, outliers) {
       expect(flatGet(typeEnv, 'outliers')).toBe('DataFrame');
     });
 
+    it('binds a formal written in backticks to the type its @param tag gives the symbol', () => {
+      const tree = parse(`
+DataFrame <- R6::R6Class("DataFrame", public = list(rows = function() 1))
+
+#' @param data DataFrame
+Summarise <- function(\`data\`) {
+  \`data\`$rows()
+}
+`);
+      const typeEnv = buildTypeEnv(tree, SupportedLanguages.R);
+      expect(flatGet(typeEnv, '`data`')).toBe('DataFrame');
+    });
+
     it('binds nothing for a type the file does not define (primitive or capitalised)', () => {
       const tree = parse(`
 #' @param x numeric