-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-
-use crate::rustc::hir;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use if_chain::if_chain;
-use crate::rustc::ty;
-use crate::rustc_errors::Applicability;
-use crate::syntax::source_map::Span;
-use crate::utils::{in_macro, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then};
use crate::utils::paths;
+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;
-#[derive(Clone)]
-pub struct Pass;
-
-/// **What it does:** Checks for usage of `option.map(f)` where f is a function
-/// or closure that returns the unit type.
-///
-/// **Why is this bad?** Readability, this can be written more clearly with
-/// an if let statement
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-///
-/// ```rust
-/// let x: Option<&str> = do_stuff();
-/// x.map(log_err_msg);
-/// x.map(|msg| log_err_msg(format_msg(msg)))
-/// ```
-///
-/// The correct use would be:
-///
-/// ```rust
-/// let x: Option<&str> = do_stuff();
-/// if let Some(msg) = x {
-/// log_err_msg(msg)
-/// }
-/// if let Some(msg) = x {
-/// log_err_msg(format_msg(msg))
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `option.map(f)` where f is a function
+ /// or closure that returns the unit type.
+ ///
+ /// **Why is this bad?** Readability, this can be written more clearly with
+ /// an if let statement
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// # 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);
+ /// # let x: Option<String> = do_stuff();
+ /// x.map(|msg| log_err_msg(format_msg(msg)));
+ /// ```
+ ///
+ /// The correct use would be:
+ ///
+ /// ```rust
+ /// # 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);
+ /// }
+ ///
+ /// # let x: Option<String> = do_stuff();
+ /// if let Some(msg) = x {
+ /// 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 ()"
}
-/// **What it does:** Checks for usage of `result.map(f)` where f is a function
-/// or closure that returns the unit type.
-///
-/// **Why is this bad?** Readability, this can be written more clearly with
-/// an if let statement
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-///
-/// ```rust
-/// let x: Result<&str, &str> = do_stuff();
-/// x.map(log_err_msg);
-/// x.map(|msg| log_err_msg(format_msg(msg)))
-/// ```
-///
-/// The correct use would be:
-///
-/// ```rust
-/// let x: Result<&str, &str> = do_stuff();
-/// if let Ok(msg) = x {
-/// log_err_msg(msg)
-/// }
-/// if let Ok(msg) = x {
-/// log_err_msg(format_msg(msg))
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `result.map(f)` where f is a function
+ /// or closure that returns the unit type.
+ ///
+ /// **Why is this bad?** Readability, this can be written more clearly with
+ /// an if let statement
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// # 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);
+ /// # let x: Result<String, String> = do_stuff();
+ /// x.map(|msg| log_err_msg(format_msg(msg)));
+ /// ```
+ ///
+ /// The correct use would be:
+ ///
+ /// ```rust
+ /// # 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);
+ /// };
+ /// # let x: Result<String, String> = do_stuff();
+ /// if let Ok(msg) = x {
+ /// 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 ()"
}
+declare_lint_pass!(MapUnit => [OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN]);
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN)
- }
-}
-
-fn is_unit_type(ty: ty::Ty<'_>) -> bool {
+fn is_unit_type(ty: Ty<'_>) -> bool {
match ty.sty {
ty::Tuple(slice) => slice.is_empty(),
ty::Never => true,
let ty = cx.tables.expr_ty(expr);
if let ty::FnDef(id, _) = ty.sty {
- if let Some(fn_type) = cx.tcx.fn_sig(id).no_late_bound_regions() {
+ if let Some(fn_type) = cx.tcx.fn_sig(id).no_bound_vars() {
return is_unit_type(fn_type.output());
}
}
}
match expr.node {
- hir::ExprKind::Call(_, _) |
- hir::ExprKind::MethodCall(_, _, _) => {
+ hir::ExprKind::Call(_, _) | hir::ExprKind::MethodCall(_, _, _) => {
// Calls can't be reduced any more
Some(expr.span)
},
// If block only contains statements,
// reduce `{ X; }` to `X` or `X;`
match inner_stmt.node {
- hir::StmtKind::Decl(ref d, _) => Some(d.span),
- hir::StmtKind::Expr(ref e, _) => Some(e.span),
- hir::StmtKind::Semi(_, _) => Some(inner_stmt.span),
+ hir::StmtKind::Local(ref local) => Some(local.span),
+ hir::StmtKind::Expr(ref e) => Some(e.span),
+ hir::StmtKind::Semi(..) => Some(inner_stmt.span),
+ hir::StmtKind::Item(..) => None,
}
},
_ => {
//
// We do not attempt to build a suggestion for those right now.
None
- }
+ },
}
},
_ => None,
}
}
-fn unit_closure<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'a hir::Expr) -> Option<(&'tcx hir::Arg, &'a hir::Expr)> {
+fn unit_closure<'a, 'tcx>(
+ cx: &LateContext<'a, 'tcx>,
+ expr: &'a hir::Expr,
+) -> Option<(&'tcx hir::Param, &'a hir::Expr)> {
if let hir::ExprKind::Closure(_, ref decl, inner_expr_id, _, _) = expr.node {
- let body = cx.tcx.hir.body(inner_expr_id);
+ let body = cx.tcx.hir().body(inner_expr_id);
let body_expr = &body.value;
if_chain! {
match &var_arg.node {
hir::ExprKind::Field(_, _) => snippet(cx, var_arg.span, "_").replace(".", "_"),
hir::ExprKind::Path(_) => format!("_{}", snippet(cx, var_arg.span, "")),
- _ => "_".to_string()
+ _ => "_".to_string(),
}
}
fn suggestion_msg(function_type: &str, map_type: &str) -> String {
format!(
"called `map(f)` on an {0} value where `f` is a unit {1}",
- map_type,
- function_type
+ map_type, function_type
)
}
fn lint_map_unit_fn(cx: &LateContext<'_, '_>, stmt: &hir::Stmt, expr: &hir::Expr, map_args: &[hir::Expr]) {
let var_arg = &map_args[0];
- let fn_arg = &map_args[1];
- let (map_type, variant, lint) =
- if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) {
- ("Option", "Some", OPTION_MAP_UNIT_FN)
- } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) {
- ("Result", "Ok", RESULT_MAP_UNIT_FN)
- } else {
- return
- };
+ let (map_type, variant, lint) = if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) {
+ ("Option", "Some", OPTION_MAP_UNIT_FN)
+ } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) {
+ ("Result", "Ok", RESULT_MAP_UNIT_FN)
+ } else {
+ return;
+ };
+ let fn_arg = &map_args[1];
if is_unit_function(cx, fn_arg) {
let msg = suggestion_msg("function", map_type);
- let suggestion = format!("if let {0}({1}) = {2} {{ {3}(...) }}",
- variant,
- let_binding_name(cx, var_arg),
- snippet(cx, var_arg.span, "_"),
- snippet(cx, fn_arg.span, "_"));
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ {3}(...) }}",
+ variant,
+ let_binding_name(cx, var_arg),
+ snippet(cx, var_arg.span, "_"),
+ snippet(cx, fn_arg.span, "_")
+ );
span_lint_and_then(cx, lint, expr.span, &msg, |db| {
- db.span_suggestion_with_applicability(stmt.span,
- "try this",
- suggestion,
- Applicability::Unspecified);
+ db.span_suggestion(stmt.span, "try this", suggestion, Applicability::Unspecified);
});
} else if let Some((binding, closure_expr)) = unit_closure(cx, fn_arg) {
let msg = suggestion_msg("closure", map_type);
span_lint_and_then(cx, lint, expr.span, &msg, |db| {
if let Some(reduced_expr_span) = reduce_unit_expression(cx, closure_expr) {
- let suggestion = format!("if let {0}({1}) = {2} {{ {3} }}",
- variant,
- snippet(cx, binding.pat.span, "_"),
- snippet(cx, var_arg.span, "_"),
- snippet(cx, reduced_expr_span, "_"));
- db.span_suggestion_with_applicability(
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ {3} }}",
+ variant,
+ snippet(cx, binding.pat.span, "_"),
+ snippet(cx, var_arg.span, "_"),
+ snippet(cx, reduced_expr_span, "_")
+ );
+ db.span_suggestion(
stmt.span,
"try this",
suggestion,
Applicability::MachineApplicable, // snippet
);
} else {
- let suggestion = format!("if let {0}({1}) = {2} {{ ... }}",
- variant,
- snippet(cx, binding.pat.span, "_"),
- snippet(cx, var_arg.span, "_"));
- db.span_suggestion_with_applicability(
- stmt.span,
- "try this",
- suggestion,
- Applicability::Unspecified,
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ ... }}",
+ variant,
+ snippet(cx, binding.pat.span, "_"),
+ snippet(cx, var_arg.span, "_")
);
+ db.span_suggestion(stmt.span, "try this", suggestion, Applicability::Unspecified);
}
});
}
}
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MapUnit {
fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt) {
- if in_macro(stmt.span) {
+ if stmt.span.from_expansion() {
return;
}
- if let hir::StmtKind::Semi(ref expr, _) = stmt.node {
+ if let hir::StmtKind::Semi(ref expr) = stmt.node {
if let Some(arglists) = method_chain_args(expr, &["map"]) {
lint_map_unit_fn(cx, stmt, expr, arglists[0]);
}
projects / rust.git / blobdiff