Merge branch 'master' of github.com:rust-lang/rust-clippy into option_if_let_else

Author: JarredAllen

.github/deploy.sh

@@ -33,7 +33,17 @@ if git diff --exit-code --quiet; then
   exit 0
 fi
 
-git add .
-git commit -m "Automatic deploy to GitHub Pages: ${SHA}"
+if [[ -n $TAG_NAME ]]; then
+  # Add the new dir
+  git add $TAG_NAME
+  # Update the symlink
+  git add stable
+  # Update versions file
+  git add versions.json
+  git commit -m "Add documentation for ${TAG_NAME} release: ${SHA}"
+else
+  git add .
+  git commit -m "Automatic deploy to GitHub Pages: ${SHA}"
+fi
 
 git push "$SSH_REPO" "$TARGET_BRANCH"

CHANGELOG.md

@@ -1209,6 +1209,7 @@ Released 2018-09-13
 [`linkedlist`]: https://rust-lang.github.io/rust-clippy/master/index.html#linkedlist
 [`logic_bug`]: https://rust-lang.github.io/rust-clippy/master/index.html#logic_bug
 [`lossy_float_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#lossy_float_literal
+[`macro_use_imports`]: https://rust-lang.github.io/rust-clippy/master/index.html#macro_use_imports
 [`main_recursion`]: https://rust-lang.github.io/rust-clippy/master/index.html#main_recursion
 [`manual_memcpy`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_memcpy
 [`manual_saturating_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_saturating_arithmetic

CONTRIBUTING.md

@@ -28,8 +28,9 @@ High level approach:
 
 1. Find something to fix/improve
 2. Change code (likely some file in `clippy_lints/src/`)
-3. Run `cargo test` in the root directory and wiggle code until it passes
-4. Open a PR (also can be done between 2. and 3. if you run into problems)
+3. Follow the instructions in the [docs for writing lints](doc/adding_lints.md) such as running the `setup-toolchain.sh` script
+4. Run `cargo test` in the root directory and wiggle code until it passes
+5. Open a PR (also can be done after 2. if you run into problems)
 
 ### Finding something to fix/improve
 

README.md

@@ -5,7 +5,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 360 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are 361 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

clippy_lints/Cargo.toml

@@ -19,7 +19,7 @@ edition = "2018"
 [dependencies]
 cargo_metadata = "0.9.0"
 if_chain = "1.0.0"
-itertools = "0.8"
+itertools = "0.9"
 lazy_static = "1.0.2"
 matches = "0.1.7"
 pulldown-cmark = { version = "0.7", default-features = false }

clippy_lints/README.md

@@ -1,3 +1 @@
-This crate contains Clippy lints. For the main crate, check
-[*crates.io*](https://crates.io/crates/clippy) or
-[GitHub](https://github.com/rust-lang/rust-clippy).
+This crate contains Clippy lints. For the main crate, check [GitHub](https://github.com/rust-lang/rust-clippy).

clippy_lints/src/implicit_return.rs

@@ -1,5 +1,5 @@
 use crate::utils::{
-    match_def_path,
+    fn_has_unsatisfiable_preds, match_def_path,
     paths::{BEGIN_PANIC, BEGIN_PANIC_FMT},
     snippet_opt, span_lint_and_then,
 };
@@ -133,6 +133,12 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitReturn {
         _: HirId,
     ) {
         let def_id = cx.tcx.hir().body_owner_def_id(body.id());
+
+        // Building MIR for `fn`s with unsatisfiable preds results in ICE.
+        if fn_has_unsatisfiable_preds(cx, def_id) {
+            return;
+        }
+
         let mir = cx.tcx.optimized_mir(def_id);
 
         // checking return type through MIR, HIR is not able to determine inferred closure return types

clippy_lints/src/lib.rs

@@ -234,6 +234,7 @@ pub mod let_underscore;
 pub mod lifetimes;
 pub mod literal_representation;
 pub mod loops;
+pub mod macro_use;
 pub mod main_recursion;
 pub mod map_clone;
 pub mod map_unit_fn;
@@ -600,6 +601,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &loops::WHILE_IMMUTABLE_CONDITION,
         &loops::WHILE_LET_LOOP,
         &loops::WHILE_LET_ON_ITERATOR,
+        &macro_use::MACRO_USE_IMPORTS,
         &main_recursion::MAIN_RECURSION,
         &map_clone::MAP_CLONE,
         &map_unit_fn::OPTION_MAP_UNIT_FN,
@@ -1015,6 +1017,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(|| box option_env_unwrap::OptionEnvUnwrap);
     store.register_late_pass(|| box wildcard_imports::WildcardImports);
     store.register_late_pass(|| box option_if_let_else::OptionIfLetElse);
+    store.register_early_pass(|| box macro_use::MacroUseImports);
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
@@ -1082,6 +1085,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&literal_representation::LARGE_DIGIT_GROUPS),
         LintId::of(&loops::EXPLICIT_INTO_ITER_LOOP),
         LintId::of(&loops::EXPLICIT_ITER_LOOP),
+        LintId::of(&macro_use::MACRO_USE_IMPORTS),
         LintId::of(&matches::SINGLE_MATCH_ELSE),
         LintId::of(&methods::FILTER_MAP),
         LintId::of(&methods::FILTER_MAP_NEXT),

clippy_lints/src/macro_use.rs

@@ -0,0 +1,53 @@
+use crate::utils::{snippet, span_lint_and_sugg};
+use if_chain::if_chain;
+use rustc_ast::ast;
+use rustc_errors::Applicability;
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::edition::Edition;
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for `#[macro_use] use...`.
+    ///
+    /// **Why is this bad?** Since the Rust 2018 edition you can import
+    /// macro's directly, this is considered idiomatic.
+    ///
+    /// **Known problems:** This lint does not generate an auto-applicable suggestion.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// #[macro_use]
+    /// use lazy_static;
+    /// ```
+    pub MACRO_USE_IMPORTS,
+    pedantic,
+    "#[macro_use] is no longer needed"
+}
+
+declare_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);
+
+impl EarlyLintPass for MacroUseImports {
+    fn check_item(&mut self, ecx: &EarlyContext<'_>, item: &ast::Item) {
+        if_chain! {
+            if ecx.sess.opts.edition == Edition::Edition2018;
+            if let ast::ItemKind::Use(use_tree) = &item.kind;
+            if let Some(mac_attr) = item
+                .attrs
+                .iter()
+                .find(|attr| attr.ident().map(|s| s.to_string()) == Some("macro_use".to_string()));
+            then {
+                let msg = "`macro_use` attributes are no longer needed in the Rust 2018 edition";
+                let help = format!("use {}::<macro name>", snippet(ecx, use_tree.span, "_"));
+                span_lint_and_sugg(
+                    ecx,
+                    MACRO_USE_IMPORTS,
+                    mac_attr.span,
+                    msg,
+                    "remove the attribute and import the macro directly, try",
+                    help,
+                    Applicability::HasPlaceholders,
+                );
+            }
+        }
+    }
+}

clippy_lints/src/map_unit_fn.rs

@@ -186,19 +186,19 @@ fn unit_closure<'a, 'tcx>(
 /// `x.field` => `x_field`
 /// `y` => `_y`
 ///
-/// Anything else will return `_`.
+/// Anything else will return `a`.
 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(),
+        _ => "a".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 {1} that returns the unit type",
         map_type, function_type
     )
 }

clippy_lints/src/matches.rs

@@ -14,8 +14,8 @@ use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::def::CtorKind;
 use rustc_hir::{
-    print, Arm, BindingAnnotation, Block, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Pat, PatKind,
-    QPath, RangeEnd,
+    print, Arm, BindingAnnotation, Block, BorrowKind, Expr, ExprKind, Local, MatchSource, Mutability, Node, Pat,
+    PatKind, QPath, RangeEnd,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
@@ -882,7 +882,7 @@ fn check_wild_in_or_pats(cx: &LateContext<'_, '_>, arms: &[Arm<'_>]) {
     }
 }
 
-fn check_match_single_binding(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
+fn check_match_single_binding<'a>(cx: &LateContext<'_, 'a>, ex: &Expr<'a>, arms: &[Arm<'_>], expr: &Expr<'_>) {
     if in_macro(expr.span) || arms.len() != 1 || is_refutable(cx, arms[0].pat) {
         return;
     }
@@ -914,19 +914,38 @@ fn check_match_single_binding(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[A
     let mut applicability = Applicability::MaybeIncorrect;
     match arms[0].pat.kind {
         PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
+            // If this match is in a local (`let`) stmt
+            let (target_span, sugg) = if let Some(parent_let_node) = opt_parent_let(cx, ex) {
+                (
+                    parent_let_node.span,
+                    format!(
+                        "let {} = {};\n{}let {} = {};",
+                        snippet_with_applicability(cx, bind_names, "..", &mut applicability),
+                        snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
+                        " ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
+                        snippet_with_applicability(cx, parent_let_node.pat.span, "..", &mut applicability),
+                        snippet_body
+                    ),
+                )
+            } else {
+                (
+                    expr.span,
+                    format!(
+                        "let {} = {};\n{}{}",
+                        snippet_with_applicability(cx, bind_names, "..", &mut applicability),
+                        snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
+                        " ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
+                        snippet_body
+                    ),
+                )
+            };
             span_lint_and_sugg(
                 cx,
                 MATCH_SINGLE_BINDING,
-                expr.span,
+                target_span,
                 "this match could be written as a `let` statement",
                 "consider using `let` statement",
-                format!(
-                    "let {} = {};\n{}{}",
-                    snippet_with_applicability(cx, bind_names, "..", &mut applicability),
-                    snippet_with_applicability(cx, matched_vars, "..", &mut applicability),
-                    " ".repeat(indent_of(cx, expr.span).unwrap_or(0)),
-                    snippet_body,
-                ),
+                sugg,
                 applicability,
             );
         },
@@ -945,6 +964,19 @@ fn check_match_single_binding(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[A
     }
 }
 
+/// Returns true if the `ex` match expression is in a local (`let`) statement
+fn opt_parent_let<'a>(cx: &LateContext<'_, 'a>, ex: &Expr<'a>) -> Option<&'a Local<'a>> {
+    if_chain! {
+        let map = &cx.tcx.hir();
+        if let Some(Node::Expr(parent_arm_expr)) = map.find(map.get_parent_node(ex.hir_id));
+        if let Some(Node::Local(parent_let_expr)) = map.find(map.get_parent_node(parent_arm_expr.hir_id));
+        then {
+            return Some(parent_let_expr);
+        }
+    }
+    None
+}
+
 /// Gets all arms that are unbounded `PatRange`s.
 fn all_ranges<'a, 'tcx>(
     cx: &LateContext<'a, 'tcx>,

clippy_lints/src/misc_early.rs

@@ -5,8 +5,8 @@ use crate::utils::{
 use if_chain::if_chain;
 use rustc::lint::in_external_macro;
 use rustc_ast::ast::{
-    Block, Expr, ExprKind, GenericParamKind, Generics, Lit, LitFloatType, LitIntType, LitKind, NodeId, Pat, PatKind,
-    StmtKind, UnOp,
+    BindingMode, Block, Expr, ExprKind, GenericParamKind, Generics, Lit, LitFloatType, LitIntType, LitKind, Mutability,
+    NodeId, Pat, PatKind, StmtKind, UnOp,
 };
 use rustc_ast::visit::{walk_expr, FnKind, Visitor};
 use rustc_data_structures::fx::FxHashMap;
@@ -318,18 +318,6 @@ impl EarlyLintPass for MiscEarlyLints {
                 return;
             }
             if wilds > 0 {
-                let mut normal = vec![];
-
-                for field in pfields {
-                    match field.pat.kind {
-                        PatKind::Wild => {},
-                        _ => {
-                            if let Ok(n) = cx.sess().source_map().span_to_snippet(field.span) {
-                                normal.push(n);
-                            }
-                        },
-                    }
-                }
                 for field in pfields {
                     if let PatKind::Wild = field.pat.kind {
                         wilds -= 1;
@@ -341,6 +329,19 @@ impl EarlyLintPass for MiscEarlyLints {
                                 "You matched a field with a wildcard pattern. Consider using `..` instead",
                             );
                         } else {
+                            let mut normal = vec![];
+
+                            for field in pfields {
+                                match field.pat.kind {
+                                    PatKind::Wild => {},
+                                    _ => {
+                                        if let Ok(n) = cx.sess().source_map().span_to_snippet(field.span) {
+                                            normal.push(n);
+                                        }
+                                    },
+                                }
+                            }
+
                             span_lint_and_help(
                                 cx,
                                 UNNEEDED_FIELD_PATTERN,
@@ -355,7 +356,13 @@ impl EarlyLintPass for MiscEarlyLints {
             }
         }
 
-        if let PatKind::Ident(_, ident, Some(ref right)) = pat.kind {
+        if let PatKind::Ident(left, ident, Some(ref right)) = pat.kind {
+            let left_binding = match left {
+                BindingMode::ByRef(Mutability::Mut) => "ref mut ",
+                BindingMode::ByRef(Mutability::Not) => "ref ",
+                _ => "",
+            };
+
             if let PatKind::Wild = right.kind {
                 span_lint_and_sugg(
                     cx,
@@ -366,7 +373,7 @@ impl EarlyLintPass for MiscEarlyLints {
                         ident.name, ident.name,
                     ),
                     "try",
-                    format!("{}", ident.name),
+                    format!("{}{}", left_binding, ident.name),
                     Applicability::MachineApplicable,
                 );
             }

clippy_lints/src/missing_const_for_fn.rs

@@ -1,4 +1,4 @@
-use crate::utils::{has_drop, is_entrypoint_fn, span_lint, trait_ref_of_method};
+use crate::utils::{fn_has_unsatisfiable_preds, has_drop, is_entrypoint_fn, span_lint, trait_ref_of_method};
 use rustc::lint::in_external_macro;
 use rustc_hir as hir;
 use rustc_hir::intravisit::FnKind;
@@ -88,6 +88,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingConstForFn {
             return;
         }
 
+        // Building MIR for `fn`s with unsatisfiable preds results in ICE.
+        if fn_has_unsatisfiable_preds(cx, def_id) {
+            return;
+        }
+
         // Perform some preliminary checks that rule out constness on the Clippy side. This way we
         // can skip the actual const check and return early.
         match kind {

clippy_lints/src/redundant_clone.rs

@@ -1,6 +1,6 @@
 use crate::utils::{
-    has_drop, is_copy, match_def_path, match_type, paths, snippet_opt, span_lint_hir, span_lint_hir_and_then,
-    walk_ptrs_ty_depth,
+    fn_has_unsatisfiable_preds, has_drop, is_copy, match_def_path, match_type, paths, snippet_opt, span_lint_hir,
+    span_lint_hir_and_then, walk_ptrs_ty_depth,
 };
 use if_chain::if_chain;
 use matches::matches;
@@ -79,6 +79,12 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for RedundantClone {
         _: HirId,
     ) {
         let def_id = cx.tcx.hir().body_owner_def_id(body.id());
+
+        // Building MIR for `fn`s with unsatisfiable preds results in ICE.
+        if fn_has_unsatisfiable_preds(cx, def_id) {
+            return;
+        }
+
         let mir = cx.tcx.optimized_mir(def_id);
         let mir_read_only = mir.unwrap_read_only();