Line continuation directly before # starts a comment that bash reads as part of the word #354

A backslash-newline (line continuation) directly before # is parsed as a separator, so the # starts a comment node. Bash removes the backslash-newline pair before it splits words, so the # is inside a word and is not a comment.

Input (a backslash at the end of line 1):

echo x\
#literal

Bash 5.3.9 prints x#literal:

$ printf 'echo x\\\n#literal\n' | bash
x#literal

tree-sitter-bash 0.25.1 (web-tree-sitter 0.27.0) parses it as a command plus a comment, with no error:

(program (command name: (command_name (word)) argument: (word)) (comment))

The comment node's text is #literal.

Expected: no comment node. The argument should cover x\ and #literal as one word or concatenation, the same way #100 made echo a\ + newline + b one concatenation.

Reproducer:

import { Parser, Language } from "web-tree-sitter";
await Parser.init();
const parser = new Parser();
parser.setLanguage(await Language.load("node_modules/tree-sitter-bash/tree-sitter-bash.wasm"));
const tree = parser.parse("echo x\\\n#literal\n");
console.log(tree.rootNode.toString());
console.log(tree.rootNode.descendantsOfType("comment").map((n) => n.text));

Related: #68 (a # that does not start a word should not begin a comment) and #100 (a newline escaped without whitespace before the backslash). This case is the continuation form of #68. We hit it in a tool that uses the comment nodes to find comments in shell scripts.