fix #24849

src/vs/base/common/uri.ts

@@ -17,7 +17,7 @@ function encodeURIComponent2(str: string): string {
 }
 
 function encodeNoop(str: string): string {
-	return str;
+	return str.replace(/[#?]/, _encode);
 }
 
 
@@ -364,10 +364,10 @@ export default class URI {
 			while (true) {
 				let idx = path.indexOf(URI._slash, lastIdx);
 				if (idx === -1) {
-					parts.push(encoder(path.substring(lastIdx)).replace(/[#?]/, _encode));
+					parts.push(encoder(path.substring(lastIdx)));
 					break;
 				}
-				parts.push(encoder(path.substring(lastIdx, idx)).replace(/[#?]/, _encode), URI._slash);
+				parts.push(encoder(path.substring(lastIdx, idx)), URI._slash);
 				lastIdx = idx + 1;
 			};
 		}

src/vs/base/test/common/uri.test.ts

@@ -399,6 +399,10 @@ suite('URI', () => {
 		uri2 = URI.parse(uri.toString());
 		assert.equal(uri2.query, 'LinkId=518008&foö&ké¥=üü');
 		assert.equal(uri2.query, uri.query);
+
+		// #24849
+		uri = URI.parse('https://twitter.com/search?src=typd&q=%23tag');
+		assert.equal(uri.toString(true), 'https://twitter.com/search?src=typd&q=%23tag');
 	});