Forbid rustdoc search query to end with ->

Author: GuillaumeGomez

src/librustdoc/html/static/js/search.js

@@ -440,6 +440,9 @@ window.initSearch = function(rawSearchIndex) {
                 // Get returned elements.
                 getItemsBefore(query, parserState, query.returned, "");
                 // Nothing can come afterward!
+                if (query.returned.length === 0) {
+                    throw new Error("Expected at least one item after `->`");
+                }
                 break;
             } else {
                 parserState.pos += 1;

src/test/rustdoc-js-std/parser-errors.js

@@ -21,6 +21,7 @@ const QUERY = [
     "a-bb",
     "a>bb",
     "ab'",
+    "a->",
 ];
 
 const PARSED = [
@@ -222,4 +223,13 @@ const PARSED = [
         userQuery: "ab'",
         error: "Unexpected `'`",
     },
+    {
+        elems: [],
+        foundElems: 0,
+        original: "a->",
+        returned: [],
+        typeFilter: -1,
+        userQuery: "a->",
+        error: "Expected at least one item after `->`",
+    },
 ];