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- Fix copy-paste error
- Check for opt.map_or argument after ensuring that opt is an Option
- Use span_lint_and_then and span_suggestion
- Update reference
This commit is contained in:
Lukas Stevens 2017-10-10 15:35:24 +02:00
parent c0fac7cf56
commit 4438c41d14
2 changed files with 25 additions and 21 deletions
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36
clippy_lints/src/methods.rs
View file

@ -208,7 +208,7 @@ declare_lint! {
pub OPTION_MAP_OR_NONE,
Warn,
"using `Option.map_or(None, f)`, which is more succinctly expressed as \
`map_or_else(g, f)`"
`and_then(f)`"
}
/// **What it does:** Checks for usage of `_.filter(_).next()`.
@ -1243,30 +1243,28 @@ fn lint_map_unwrap_or_else<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir
/// lint use of `_.map_or(None, _)` for `Option`s
fn lint_map_or_none<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, map_or_args: &'tcx [hir::Expr]) {
// check if the first non-self argument to map_or() is None
let map_or_arg_is_none = if let hir::Expr_::ExprPath(ref qpath) = map_or_args[1].node {
match_qpath(qpath, &paths::OPTION_NONE)
} else {
false
};
if match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::OPTION) && map_or_arg_is_none {
// lint message
let msg = "called `map_or(None, f)` on an Option value. This can be done more directly by calling \
`and_then(f)` instead";
let map_or_none_snippet = snippet(cx, map_or_args[1].span, "..");
let map_or_func_snippet = snippet(cx, map_or_args[2].span, "..");
let multiline = map_or_func_snippet.lines().count() > 1 || map_or_none_snippet.lines().count() > 1;
if multiline {
span_lint(cx, OPTION_MAP_OR_NONE, expr.span, msg);
if match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::OPTION) {
// check if the first non-self argument to map_or() is None
let map_or_arg_is_none = if let hir::Expr_::ExprPath(ref qpath) = map_or_args[1].node {
match_qpath(qpath, &paths::OPTION_NONE)
} else {
span_note_and_lint(
false
};
if map_or_arg_is_none {
// lint message
let msg = "called `map_or(None, f)` on an Option value. This can be done more directly by calling \
`and_then(f)` instead";
let map_or_self_snippet = snippet(cx, map_or_args[0].span, "..");
let map_or_func_snippet = snippet(cx, map_or_args[2].span, "..");
let hint = format!("{0}.and_then({1})", map_or_self_snippet, map_or_func_snippet);
span_lint_and_then(
cx,
OPTION_MAP_OR_NONE,
expr.span,
msg,
expr.span,
&format!("replace `map_or({0}, {1})` with `and_then({1})`", map_or_none_snippet, map_or_func_snippet)
|db| { db.span_suggestion(expr.span, "try using and_then instead", hint); },
);
}
}

10
tests/ui/methods.stderr
View file

@ -199,10 +199,9 @@ error: called `map_or(None, f)` on an Option value. This can be done more direct
--> $DIR/methods.rs:144:13
|
144 | let _ = opt.map_or(None, |x| Some(x + 1));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using and_then instead: `opt.and_then(|x| Some(x + 1))`
|
= note: `-D option-map-or-none` implied by `-D warnings`
= note: replace `map_or(None, |x| Some(x + 1))` with `and_then(|x| Some(x + 1))`
error: called `map_or(None, f)` on an Option value. This can be done more directly by calling `and_then(f)` instead
--> $DIR/methods.rs:146:13
@ -213,6 +212,13 @@ error: called `map_or(None, f)` on an Option value. This can be done more direct
148 | | }
149 | | );
| |_________________^
|
help: try using and_then instead
|
146 | let _ = opt.and_then(|x| {
147 | Some(x + 1)
148 | });
|
error: unnecessary structure name repetition
--> $DIR/methods.rs:173:24