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use crate::{make, Metadata, Report, Rule, Suggestion};
use if_chain::if_chain;
use macros::lint;
use rnix::{
types::{EntryHolder, Ident, Key, LegacyLet, TokenWrapper, TypedNode},
NodeOrToken, SyntaxElement, SyntaxKind,
};
/// ## What it does
/// Checks for legacy-let syntax that was never formalized.
///
/// ## Why is this bad?
/// This syntax construct is undocumented, refrain from using it.
///
/// ## Example
///
/// Legacy let syntax makes use of an attribute set annotated with
/// `let` and expects a `body` attribute.
/// ```nix
/// let {
/// body = x + y;
/// x = 2;
/// y = 3;
/// }
/// ```
///
/// This is trivially representible via `rec`, which is documented
/// and more widely known:
///
/// ```nix
/// rec {
/// body = x + y;
/// x = 2;
/// y = 3;
/// }.body
/// ```
#[lint(
name = "legacy_let_syntax",
note = "Using undocumented `let` syntax",
code = 5,
match_with = SyntaxKind::NODE_LEGACY_LET
)]
struct ManualInherit;
impl Rule for ManualInherit {
fn validate(&self, node: &SyntaxElement) -> Option<Report> {
if_chain! {
if let NodeOrToken::Node(node) = node;
if let Some(legacy_let) = LegacyLet::cast(node.clone());
if legacy_let
.entries()
.any(|kv| matches!(kv.key(), Some(k) if key_is_ident(&k, "body")));
then {
let inherits = legacy_let.inherits();
let entries = legacy_let.entries();
let attrset = make::attrset(inherits, entries, true);
let parenthesized = make::parenthesize(attrset.node());
let selected = make::select(parenthesized.node(), make::ident("body").node());
let at = node.text_range();
let message = "Prefer `rec` over undocumented `let` syntax";
let replacement = selected.node().clone();
Some(self.report().suggest(at, message, Suggestion::new(at, replacement)))
} else {
None
}
}
}
}
fn key_is_ident(key_path: &Key, ident: &str) -> bool {
if let Some(key_node) = key_path.path().next() {
if let Some(key) = Ident::cast(key_node) {
return key.as_str() == ident;
}
}
false
}
|
