use crate::utils::paths;
-use crate::utils::{in_macro_or_desugar, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then};
+use crate::utils::{iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then};
use if_chain::if_chain;
-use rustc::hir;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::ty::{self, Ty};
-use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
-use syntax::source_map::Span;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Span;
declare_clippy_lint! {
/// **What it does:** Checks for usage of `option.map(f)` where f is a function
/// **Example:**
///
/// ```rust
- /// let x: Option<&str> = do_stuff();
+ /// # fn do_stuff() -> Option<String> { Some(String::new()) }
+ /// # fn log_err_msg(foo: String) -> Option<String> { Some(foo) }
+ /// # fn format_msg(foo: String) -> String { String::new() }
+ /// let x: Option<String> = do_stuff();
/// x.map(log_err_msg);
- /// x.map(|msg| log_err_msg(format_msg(msg)))
+ /// # let x: Option<String> = do_stuff();
+ /// x.map(|msg| log_err_msg(format_msg(msg)));
/// ```
///
/// The correct use would be:
///
/// ```rust
- /// let x: Option<&str> = do_stuff();
+ /// # fn do_stuff() -> Option<String> { Some(String::new()) }
+ /// # fn log_err_msg(foo: String) -> Option<String> { Some(foo) }
+ /// # fn format_msg(foo: String) -> String { String::new() }
+ /// let x: Option<String> = do_stuff();
/// if let Some(msg) = x {
- /// log_err_msg(msg)
+ /// log_err_msg(msg);
/// }
+ ///
+ /// # let x: Option<String> = do_stuff();
/// if let Some(msg) = x {
- /// log_err_msg(format_msg(msg))
+ /// log_err_msg(format_msg(msg));
/// }
/// ```
pub OPTION_MAP_UNIT_FN,
complexity,
- "using `option.map(f)`, where f is a function or closure that returns ()"
+ "using `option.map(f)`, where `f` is a function or closure that returns `()`"
}
declare_clippy_lint! {
/// **Example:**
///
/// ```rust
- /// let x: Result<&str, &str> = do_stuff();
+ /// # fn do_stuff() -> Result<String, String> { Ok(String::new()) }
+ /// # fn log_err_msg(foo: String) -> Result<String, String> { Ok(foo) }
+ /// # fn format_msg(foo: String) -> String { String::new() }
+ /// let x: Result<String, String> = do_stuff();
/// x.map(log_err_msg);
- /// x.map(|msg| log_err_msg(format_msg(msg)))
+ /// # let x: Result<String, String> = do_stuff();
+ /// x.map(|msg| log_err_msg(format_msg(msg)));
/// ```
///
/// The correct use would be:
///
/// ```rust
- /// let x: Result<&str, &str> = do_stuff();
+ /// # fn do_stuff() -> Result<String, String> { Ok(String::new()) }
+ /// # fn log_err_msg(foo: String) -> Result<String, String> { Ok(foo) }
+ /// # fn format_msg(foo: String) -> String { String::new() }
+ /// let x: Result<String, String> = do_stuff();
/// if let Ok(msg) = x {
- /// log_err_msg(msg)
- /// }
+ /// log_err_msg(msg);
+ /// };
+ /// # let x: Result<String, String> = do_stuff();
/// if let Ok(msg) = x {
- /// log_err_msg(format_msg(msg))
- /// }
+ /// log_err_msg(format_msg(msg));
+ /// };
/// ```
pub RESULT_MAP_UNIT_FN,
complexity,
- "using `result.map(f)`, where f is a function or closure that returns ()"
+ "using `result.map(f)`, where `f` is a function or closure that returns `()`"
}
declare_lint_pass!(MapUnit => [OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN]);
fn is_unit_type(ty: Ty<'_>) -> bool {
- match ty.sty {
+ match ty.kind {
ty::Tuple(slice) => slice.is_empty(),
ty::Never => true,
_ => false,
}
}
-fn is_unit_function(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> bool {
+fn is_unit_function(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) -> bool {
let ty = cx.tables.expr_ty(expr);
- if let ty::FnDef(id, _) = ty.sty {
+ if let ty::FnDef(id, _) = ty.kind {
if let Some(fn_type) = cx.tcx.fn_sig(id).no_bound_vars() {
return is_unit_type(fn_type.output());
}
false
}
-fn is_unit_expression(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> bool {
+fn is_unit_expression(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) -> bool {
is_unit_type(cx.tables.expr_ty(expr))
}
/// semicolons, which causes problems when generating a suggestion. Given an
/// expression that evaluates to '()' or '!', recursively remove useless braces
/// and semi-colons until is suitable for including in the suggestion template
-fn reduce_unit_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a hir::Expr) -> Option<Span> {
+fn reduce_unit_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a hir::Expr<'_>) -> Option<Span> {
if !is_unit_expression(cx, expr) {
return None;
}
- match expr.node {
+ match expr.kind {
hir::ExprKind::Call(_, _) | hir::ExprKind::MethodCall(_, _, _) => {
// Calls can't be reduced any more
Some(expr.span)
(&[ref inner_stmt], None) => {
// If block only contains statements,
// reduce `{ X; }` to `X` or `X;`
- match inner_stmt.node {
+ match inner_stmt.kind {
hir::StmtKind::Local(ref local) => Some(local.span),
hir::StmtKind::Expr(ref e) => Some(e.span),
hir::StmtKind::Semi(..) => Some(inner_stmt.span),
}
}
-fn unit_closure<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'a hir::Expr) -> Option<(&'tcx hir::Arg, &'a hir::Expr)> {
- if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.node {
+fn unit_closure<'a, 'tcx>(
+ cx: &LateContext<'a, 'tcx>,
+ expr: &'a hir::Expr<'a>,
+) -> Option<(&'tcx hir::Param<'tcx>, &'a hir::Expr<'a>)> {
+ if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.kind {
let body = cx.tcx.hir().body(inner_expr_id);
let body_expr = &body.value;
/// `y` => `_y`
///
/// Anything else will return `_`.
-fn let_binding_name(cx: &LateContext<'_, '_>, var_arg: &hir::Expr) -> String {
- match &var_arg.node {
+fn let_binding_name(cx: &LateContext<'_, '_>, var_arg: &hir::Expr<'_>) -> String {
+ match &var_arg.kind {
hir::ExprKind::Field(_, _) => snippet(cx, var_arg.span, "_").replace(".", "_"),
hir::ExprKind::Path(_) => format!("_{}", snippet(cx, var_arg.span, "")),
_ => "_".to_string(),
}
}
+#[must_use]
fn suggestion_msg(function_type: &str, map_type: &str) -> String {
format!(
- "called `map(f)` on an {0} value where `f` is a unit {1}",
+ "called `map(f)` on an `{0}` value where `f` is a unit {1}",
map_type, function_type
)
}
-fn lint_map_unit_fn(cx: &LateContext<'_, '_>, stmt: &hir::Stmt, expr: &hir::Expr, map_args: &[hir::Expr]) {
+fn lint_map_unit_fn(cx: &LateContext<'_, '_>, stmt: &hir::Stmt<'_>, expr: &hir::Expr<'_>, map_args: &[hir::Expr<'_>]) {
let var_arg = &map_args[0];
let (map_type, variant, lint) = if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) {
if is_unit_function(cx, fn_arg) {
let msg = suggestion_msg("function", map_type);
let suggestion = format!(
- "if let {0}({1}) = {2} {{ {3}(...) }}",
+ "if let {0}({binding}) = {1} {{ {2}({binding}) }}",
variant,
- let_binding_name(cx, var_arg),
snippet(cx, var_arg.span, "_"),
- snippet(cx, fn_arg.span, "_")
+ snippet(cx, fn_arg.span, "_"),
+ binding = let_binding_name(cx, var_arg)
);
span_lint_and_then(cx, lint, expr.span, &msg, |db| {
- db.span_suggestion(stmt.span, "try this", suggestion, Applicability::Unspecified);
+ db.span_suggestion(stmt.span, "try this", suggestion, Applicability::MachineApplicable);
});
} else if let Some((binding, closure_expr)) = unit_closure(cx, fn_arg) {
let msg = suggestion_msg("closure", map_type);
"if let {0}({1}) = {2} {{ ... }}",
variant,
snippet(cx, binding.pat.span, "_"),
- snippet(cx, var_arg.span, "_")
+ snippet(cx, var_arg.span, "_"),
);
- db.span_suggestion(stmt.span, "try this", suggestion, Applicability::Unspecified);
+ db.span_suggestion(stmt.span, "try this", suggestion, Applicability::HasPlaceholders);
}
});
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MapUnit {
- fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt) {
- if in_macro_or_desugar(stmt.span) {
+ fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt<'_>) {
+ if stmt.span.from_expansion() {
return;
}
- if let hir::StmtKind::Semi(ref expr) = stmt.node {
+ if let hir::StmtKind::Semi(ref expr) = stmt.kind {
if let Some(arglists) = method_chain_args(expr, &["map"]) {
lint_map_unit_fn(cx, stmt, expr, arglists[0]);
}
projects / rust.git / blobdiff