Rollup merge of #96754 - notriddle:notriddle/impl-dups, r=GuillaumeGomez

rustdoc: ensure HTML/JS side implementors don't have dups

Fixes #94641

Rendered:

- https://notriddle.com/notriddle-rustdoc-test/impl-dups/std/iter/trait.Iterator.html
- https://notriddle.com/notriddle-rustdoc-test/impl-dups/core/iter/trait.Iterator.html

1 files changed, 7 insertions, 1 deletions

diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index 66a7d484f33..2d8339e8394 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -759,8 +759,14 @@ function loadCss(cssFileName) {
         const traitName = document.querySelector("h1.fqn > .in-band > .trait").textContent;
         const baseIdName = "impl-" + traitName + "-";
         const libs = Object.getOwnPropertyNames(imp);
+        // We don't want to include impls from this JS file, when the HTML already has them.
+        // The current crate should always be ignored. Other crates that should also be
+        // ignored are included in the attribute `data-ignore-extern-crates`.
+        const ignoreExternCrates = document
+            .querySelector("script[data-ignore-extern-crates]")
+            .getAttribute("data-ignore-extern-crates");
         for (const lib of libs) {
-            if (lib === window.currentCrate) {
+            if (lib === window.currentCrate || ignoreExternCrates.indexOf(lib) !== -1) {
                 continue;
             }
             const structs = imp[lib];