From 3699e939e8f6a2517806a219c082723d50dd4288 Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Thu, 5 Sep 2024 17:58:05 -0700
Subject: [PATCH] rustdoc-search: allow trailing `Foo ->` arg search

---
 src/librustdoc/html/static/js/externs.js |  1 +
 src/librustdoc/html/static/js/search.js  | 10 ++--
 tests/rustdoc-js-std/parser-errors.js    |  9 ----
 tests/rustdoc-js-std/parser-returned.js  | 68 ++++++++++++++++++++++++
 tests/rustdoc-js/never-search.js         |  7 +++
 5 files changed, 81 insertions(+), 14 deletions(-)

diff --git a/src/librustdoc/html/static/js/externs.js b/src/librustdoc/html/static/js/externs.js
index 6fd60d6cc34..3d3e0a8f838 100644
--- a/src/librustdoc/html/static/js/externs.js
+++ b/src/librustdoc/html/static/js/externs.js
@@ -41,6 +41,7 @@ let ParserState;
  *     foundElems: number,
  *     totalElems: number,
  *     literalSearch: boolean,
+ *     hasReturnArrow: boolean,
  *     corrections: Array<{from: string, to: integer}> | null,
  *     typeFingerprint: Uint32Array,
  *     error: Array<string> | null,
diff --git a/src/librustdoc/html/static/js/search.js b/src/librustdoc/html/static/js/search.js
index 6f575e60ed4..4da0bbc787d 100644
--- a/src/librustdoc/html/static/js/search.js
+++ b/src/librustdoc/html/static/js/search.js
@@ -657,7 +657,7 @@ function createQueryElement(query, parserState, name, generics, isInGenerics) {
     }
     const typeFilter = parserState.typeFilter;
     parserState.typeFilter = null;
-    if (name === "!") {
+    if (name.trim() === "!") {
         if (typeFilter !== null && typeFilter !== "primitive") {
             throw [
                 "Invalid search type: primitive never type ",
@@ -1795,6 +1795,7 @@ class DocSearch {
                 // Total number of elements (includes generics).
                 totalElems: 0,
                 literalSearch: false,
+                hasReturnArrow: false,
                 error: null,
                 correction: null,
                 proposeCorrectionFrom: null,
@@ -1823,6 +1824,7 @@ class DocSearch {
                         continue;
                     } else if (c === "-" || c === ">") {
                         if (isReturnArrow(parserState)) {
+                            query.hasReturnArrow = true;
                             break;
                         }
                         throw ["Unexpected ", c, " (did you mean ", "->", "?)"];
@@ -1889,9 +1891,7 @@ class DocSearch {
                     // Get returned elements.
                     getItemsBefore(query, parserState, query.returned, "");
                     // Nothing can come afterward!
-                    if (query.returned.length === 0) {
-                        throw ["Expected at least one item after ", "->"];
-                    }
+                    query.hasReturnArrow = true;
                     break;
                 } else {
                     parserState.pos += 1;
@@ -3249,7 +3249,7 @@ class DocSearch {
                 this.buildFunctionTypeFingerprint(elem, parsedQuery.typeFingerprint, fps);
             }
 
-            if (parsedQuery.foundElems === 1 && parsedQuery.returned.length === 0) {
+            if (parsedQuery.foundElems === 1 && !parsedQuery.hasReturnArrow) {
                 if (parsedQuery.elems.length === 1) {
                     const elem = parsedQuery.elems[0];
                     const length = this.searchIndex.length;
diff --git a/tests/rustdoc-js-std/parser-errors.js b/tests/rustdoc-js-std/parser-errors.js
index c4d7c2b0b85..5ce35bf511d 100644
--- a/tests/rustdoc-js-std/parser-errors.js
+++ b/tests/rustdoc-js-std/parser-errors.js
@@ -251,15 +251,6 @@ const PARSED = [
         userQuery: "ab'",
         error: "Unexpected `'` after `b` (not a valid identifier)",
     },
-    {
-        query: "a->",
-        elems: [],
-        foundElems: 0,
-        original: "a->",
-        returned: [],
-        userQuery: "a->",
-        error: "Expected at least one item after `->`",
-    },
     {
         query: '"p" <a>',
         elems: [],
diff --git a/tests/rustdoc-js-std/parser-returned.js b/tests/rustdoc-js-std/parser-returned.js
index 44e517c49b5..8f68209bb96 100644
--- a/tests/rustdoc-js-std/parser-returned.js
+++ b/tests/rustdoc-js-std/parser-returned.js
@@ -94,4 +94,72 @@ const PARSED = [
         userQuery: "-> !",
         error: null,
     },
+    {
+        query: "a->",
+        elems: [{
+            name: "a",
+            fullPath: ["a"],
+            pathWithoutLast: [],
+            pathLast: "a",
+            generics: [],
+            typeFilter: -1,
+        }],
+        foundElems: 1,
+        original: "a->",
+        returned: [],
+        userQuery: "a->",
+        hasReturnArrow: true,
+        error: null,
+    },
+    {
+        query: "!->",
+        elems: [{
+            name: "never",
+            fullPath: ["never"],
+            pathWithoutLast: [],
+            pathLast: "never",
+            generics: [],
+            typeFilter: 1,
+        }],
+        foundElems: 1,
+        original: "!->",
+        returned: [],
+        userQuery: "!->",
+        hasReturnArrow: true,
+        error: null,
+    },
+    {
+        query: "! ->",
+        elems: [{
+            name: "never",
+            fullPath: ["never"],
+            pathWithoutLast: [],
+            pathLast: "never",
+            generics: [],
+            typeFilter: 1,
+        }],
+        foundElems: 1,
+        original: "! ->",
+        returned: [],
+        userQuery: "! ->",
+        hasReturnArrow: true,
+        error: null,
+    },
+    {
+        query: "primitive:!->",
+        elems: [{
+            name: "never",
+            fullPath: ["never"],
+            pathWithoutLast: [],
+            pathLast: "never",
+            generics: [],
+            typeFilter: 1,
+        }],
+        foundElems: 1,
+        original: "primitive:!->",
+        returned: [],
+        userQuery: "primitive:!->",
+        hasReturnArrow: true,
+        error: null,
+    },
 ];
diff --git a/tests/rustdoc-js/never-search.js b/tests/rustdoc-js/never-search.js
index 9f18370c2f5..9cc62a5ed04 100644
--- a/tests/rustdoc-js/never-search.js
+++ b/tests/rustdoc-js/never-search.js
@@ -1,6 +1,13 @@
 // exact-check
 
 const EXPECTED = [
+    {
+        'query': '! ->',
+        'others': [
+            { 'path': 'never_search', 'name': 'impossible' },
+            { 'path': 'never_search', 'name': 'box_impossible' },
+        ],
+    },
     {
         'query': '-> !',
         'others': [