Merge remote-tracking branch 'upstream/master' into rustup

Author: flip1995

clippy_lints/src/lib.rs

@@ -1062,7 +1062,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(|| box option_env_unwrap::OptionEnvUnwrap);
     let warn_on_all_wildcard_imports = conf.warn_on_all_wildcard_imports;
     store.register_late_pass(move || box wildcard_imports::WildcardImports::new(warn_on_all_wildcard_imports));
-    store.register_early_pass(|| box macro_use::MacroUseImports);
     store.register_late_pass(|| box verbose_file_reads::VerboseFileReads);
     store.register_late_pass(|| box redundant_pub_crate::RedundantPubCrate::default());
     store.register_late_pass(|| box unnamed_address::UnnamedAddress);
@@ -1080,6 +1079,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         single_char_binding_names_threshold,
     });
     store.register_early_pass(|| box unnested_or_patterns::UnnestedOrPatterns);
+    store.register_late_pass(|| box macro_use::MacroUseImports::default());
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),

clippy_lints/src/macro_use.rs

@@ -1,18 +1,21 @@
-use crate::utils::{snippet, span_lint_and_sugg};
+use crate::utils::{in_macro, snippet, span_lint_and_sugg};
+use hir::def::{DefKind, Res};
 use if_chain::if_chain;
 use rustc_ast::ast;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::Applicability;
-use rustc_lint::{EarlyContext, EarlyLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::edition::Edition;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::{edition::Edition, Span};
 
 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.
+    /// **Known problems:** None.
     ///
     /// **Example:**
     /// ```rust
@@ -24,29 +27,205 @@ declare_clippy_lint! {
     "#[macro_use] is no longer needed"
 }
 
-declare_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);
+const BRACKETS: &[char] = &['<', '>'];
 
-impl EarlyLintPass for MacroUseImports {
-    fn check_item(&mut self, ecx: &EarlyContext<'_>, item: &ast::Item) {
+#[derive(Clone, Debug, PartialEq, Eq)]
+struct PathAndSpan {
+    path: String,
+    span: Span,
+}
+
+/// `MacroRefData` includes the name of the macro
+/// and the path from `SourceMap::span_to_filename`.
+#[derive(Debug, Clone)]
+pub struct MacroRefData {
+    name: String,
+    path: String,
+}
+
+impl MacroRefData {
+    pub fn new(name: String, callee: Span, cx: &LateContext<'_, '_>) -> Self {
+        let mut path = cx.sess().source_map().span_to_filename(callee).to_string();
+
+        // std lib paths are <::std::module::file type>
+        // so remove brackets, space and type.
+        if path.contains('<') {
+            path = path.replace(BRACKETS, "");
+        }
+        if path.contains(' ') {
+            path = path.split(' ').next().unwrap().to_string();
+        }
+        Self { name, path }
+    }
+}
+
+#[derive(Default)]
+#[allow(clippy::module_name_repetitions)]
+pub struct MacroUseImports {
+    /// the actual import path used and the span of the attribute above it.
+    imports: Vec<(String, Span)>,
+    /// the span of the macro reference, kept to ensure only one reference is used per macro call.
+    collected: FxHashSet<Span>,
+    mac_refs: Vec<MacroRefData>,
+}
+
+impl_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);
+
+impl MacroUseImports {
+    fn push_unique_macro(&mut self, cx: &LateContext<'_, '_>, span: Span) {
+        let call_site = span.source_callsite();
+        let name = snippet(cx, cx.sess().source_map().span_until_char(call_site, '!'), "_");
+        if let Some(callee) = span.source_callee() {
+            if !self.collected.contains(&call_site) {
+                let name = if name.contains("::") {
+                    name.split("::").last().unwrap().to_string()
+                } else {
+                    name.to_string()
+                };
+
+                self.mac_refs.push(MacroRefData::new(name, callee.def_site, cx));
+                self.collected.insert(call_site);
+            }
+        }
+    }
+
+    fn push_unique_macro_pat_ty(&mut self, cx: &LateContext<'_, '_>, span: Span) {
+        let call_site = span.source_callsite();
+        let name = snippet(cx, cx.sess().source_map().span_until_char(call_site, '!'), "_");
+        if let Some(callee) = span.source_callee() {
+            if !self.collected.contains(&call_site) {
+                self.mac_refs
+                    .push(MacroRefData::new(name.to_string(), callee.def_site, cx));
+                self.collected.insert(call_site);
+            }
+        }
+    }
+}
+
+impl<'l, 'txc> LateLintPass<'l, 'txc> for MacroUseImports {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item<'_>) {
         if_chain! {
-            if ecx.sess.opts.edition == Edition::Edition2018;
-            if let ast::ItemKind::Use(use_tree) = &item.kind;
+            if cx.sess().opts.edition == Edition::Edition2018;
+            if let hir::ItemKind::Use(path, _kind) = &item.kind;
             if let Some(mac_attr) = item
                 .attrs
                 .iter()
                 .find(|attr| attr.ident().map(|s| s.to_string()) == Some("macro_use".to_string()));
+            if let Res::Def(DefKind::Mod, id) = path.res;
             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, "_"));
+                for kid in cx.tcx.item_children(id).iter() {
+                    if let Res::Def(DefKind::Macro(_mac_type), mac_id) = kid.res {
+                        let span = mac_attr.span;
+                        let def_path = cx.tcx.def_path_str(mac_id);
+                        self.imports.push((def_path, span));
+                    }
+                }
+            } else {
+                if in_macro(item.span) {
+                    self.push_unique_macro_pat_ty(cx, item.span);
+                }
+            }
+        }
+    }
+    fn check_attribute(&mut self, cx: &LateContext<'_, '_>, attr: &ast::Attribute) {
+        if in_macro(attr.span) {
+            self.push_unique_macro(cx, attr.span);
+        }
+    }
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) {
+        if in_macro(expr.span) {
+            self.push_unique_macro(cx, expr.span);
+        }
+    }
+    fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt<'_>) {
+        if in_macro(stmt.span) {
+            self.push_unique_macro(cx, stmt.span);
+        }
+    }
+    fn check_pat(&mut self, cx: &LateContext<'_, '_>, pat: &hir::Pat<'_>) {
+        if in_macro(pat.span) {
+            self.push_unique_macro_pat_ty(cx, pat.span);
+        }
+    }
+    fn check_ty(&mut self, cx: &LateContext<'_, '_>, ty: &hir::Ty<'_>) {
+        if in_macro(ty.span) {
+            self.push_unique_macro_pat_ty(cx, ty.span);
+        }
+    }
+    #[allow(clippy::too_many_lines)]
+    fn check_crate_post(&mut self, cx: &LateContext<'_, '_>, _krate: &hir::Crate<'_>) {
+        let mut used = FxHashMap::default();
+        let mut check_dup = vec![];
+        for (import, span) in &self.imports {
+            let found_idx = self.mac_refs.iter().position(|mac| import.ends_with(&mac.name));
+
+            if let Some(idx) = found_idx {
+                let _ = self.mac_refs.remove(idx);
+                let seg = import.split("::").collect::<Vec<_>>();
+
+                match seg.as_slice() {
+                    // an empty path is impossible
+                    // a path should always consist of 2 or more segments
+                    [] | [_] => return,
+                    [root, item] => {
+                        if !check_dup.contains(&(*item).to_string()) {
+                            used.entry(((*root).to_string(), span))
+                                .or_insert_with(Vec::new)
+                                .push((*item).to_string());
+                            check_dup.push((*item).to_string());
+                        }
+                    },
+                    [root, rest @ ..] => {
+                        if rest.iter().all(|item| !check_dup.contains(&(*item).to_string())) {
+                            let filtered = rest
+                                .iter()
+                                .filter_map(|item| {
+                                    if check_dup.contains(&(*item).to_string()) {
+                                        None
+                                    } else {
+                                        Some((*item).to_string())
+                                    }
+                                })
+                                .collect::<Vec<_>>();
+                            used.entry(((*root).to_string(), span))
+                                .or_insert_with(Vec::new)
+                                .push(filtered.join("::"));
+                            check_dup.extend(filtered);
+                        } else {
+                            let rest = rest.to_vec();
+                            used.entry(((*root).to_string(), span))
+                                .or_insert_with(Vec::new)
+                                .push(rest.join("::"));
+                            check_dup.extend(rest.iter().map(ToString::to_string));
+                        }
+                    },
+                }
+            }
+        }
+
+        let mut suggestions = vec![];
+        for ((root, span), path) in used {
+            if path.len() == 1 {
+                suggestions.push((span, format!("{}::{}", root, path[0])))
+            } else {
+                suggestions.push((span, format!("{}::{{{}}}", root, path.join(", "))))
+            }
+        }
+
+        // If mac_refs is not empty we have encountered an import we could not handle
+        // such as `std::prelude::v1::foo` or some other macro that expands to an import.
+        if self.mac_refs.is_empty() {
+            for (span, import) in suggestions {
+                let help = format!("use {};", import);
                 span_lint_and_sugg(
-                    ecx,
+                    cx,
                     MACRO_USE_IMPORTS,
-                    mac_attr.span,
-                    msg,
+                    *span,
+                    "`macro_use` attributes are no longer needed in the Rust 2018 edition",
                     "remove the attribute and import the macro directly, try",
                     help,
-                    Applicability::HasPlaceholders,
-                );
+                    Applicability::MaybeIncorrect,
+                )
             }
         }
     }

clippy_lints/src/needless_pass_by_value.rs

@@ -40,9 +40,8 @@ declare_clippy_lint! {
     ///     assert_eq!(v.len(), 42);
     /// }
     /// ```
-    ///
+    /// should be
     /// ```rust
-    /// // should be
     /// fn foo(v: &[i32]) {
     ///     assert_eq!(v.len(), 42);
     /// }
@@ -173,13 +172,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessPassByValue {
                     !preds.is_empty() && {
                         let ty_empty_region = cx.tcx.mk_imm_ref(cx.tcx.lifetimes.re_root_empty, ty);
                         preds.iter().all(|t| {
-                            let ty_params = &t
-                                .skip_binder()
-                                .trait_ref
-                                .substs
-                                .iter()
-                                .skip(1)
-                                .collect::<Vec<_>>();
+                            let ty_params = &t.skip_binder().trait_ref.substs.iter().skip(1).collect::<Vec<_>>();
                             implements_trait(cx, ty_empty_region, t.def_id(), ty_params)
                         })
                     },

clippy_lints/src/utils/hir_utils.rs

@@ -309,18 +309,15 @@ fn swap_binop<'a>(
     rhs: &'a Expr<'a>,
 ) -> Option<(BinOpKind, &'a Expr<'a>, &'a Expr<'a>)> {
     match binop {
-        BinOpKind::Add
-        | BinOpKind::Mul
-        | BinOpKind::Eq
-        | BinOpKind::Ne
-        | BinOpKind::BitAnd
-        | BinOpKind::BitXor
-        | BinOpKind::BitOr => Some((binop, rhs, lhs)),
+        BinOpKind::Add | BinOpKind::Eq | BinOpKind::Ne | BinOpKind::BitAnd | BinOpKind::BitXor | BinOpKind::BitOr => {
+            Some((binop, rhs, lhs))
+        },
         BinOpKind::Lt => Some((BinOpKind::Gt, rhs, lhs)),
         BinOpKind::Le => Some((BinOpKind::Ge, rhs, lhs)),
         BinOpKind::Ge => Some((BinOpKind::Le, rhs, lhs)),
         BinOpKind::Gt => Some((BinOpKind::Lt, rhs, lhs)),
-        BinOpKind::Shl
+        BinOpKind::Mul // Not always commutative, e.g. with matrices. See issue #5698
+        | BinOpKind::Shl
         | BinOpKind::Shr
         | BinOpKind::Rem
         | BinOpKind::Sub

clippy_lints/src/write.rs

@@ -23,7 +23,11 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
+    /// // Bad
     /// println!("");
+    ///
+    /// // Good
+    /// println!();
     /// ```
     pub PRINTLN_EMPTY_STRING,
     style,
@@ -32,8 +36,7 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// **What it does:** This lint warns when you use `print!()` with a format
-    /// string that
-    /// ends in a newline.
+    /// string that ends in a newline.
     ///
     /// **Why is this bad?** You should use `println!()` instead, which appends the
     /// newline.
@@ -125,7 +128,12 @@ declare_clippy_lint! {
     /// ```rust
     /// # use std::fmt::Write;
     /// # let mut buf = String::new();
+    ///
+    /// // Bad
     /// writeln!(buf, "");
+    ///
+    /// // Good
+    /// writeln!(buf);
     /// ```
     pub WRITELN_EMPTY_STRING,
     style,
@@ -147,7 +155,12 @@ declare_clippy_lint! {
     /// # use std::fmt::Write;
     /// # let mut buf = String::new();
     /// # let name = "World";
+    ///
+    /// // Bad
     /// write!(buf, "Hello {}!\n", name);
+    ///
+    /// // Good
+    /// writeln!(buf, "Hello {}!", name);
     /// ```
     pub WRITE_WITH_NEWLINE,
     style,
@@ -168,7 +181,12 @@ declare_clippy_lint! {
     /// ```rust
     /// # use std::fmt::Write;
     /// # let mut buf = String::new();
+    ///
+    /// // Bad
     /// writeln!(buf, "{}", "foo");
+    ///
+    /// // Good
+    /// writeln!(buf, "foo");
     /// ```
     pub WRITE_LITERAL,
     style,
@@ -279,12 +297,11 @@ impl EarlyLintPass for Write {
             if let (Some(fmt_str), expr) = self.check_tts(cx, &mac.args.inner_tokens(), true) {
                 if fmt_str.symbol == Symbol::intern("") {
                     let mut applicability = Applicability::MachineApplicable;
-                    let suggestion = match expr {
-                        Some(expr) => snippet_with_applicability(cx, expr.span, "v", &mut applicability),
-                        None => {
-                            applicability = Applicability::HasPlaceholders;
-                            Cow::Borrowed("v")
-                        },
+                    let suggestion = if let Some(e) = expr {
+                        snippet_with_applicability(cx, e.span, "v", &mut applicability)
+                    } else {
+                        applicability = Applicability::HasPlaceholders;
+                        Cow::Borrowed("v")
                     };
 
                     span_lint_and_sugg(

tests/compile-test.rs

@@ -153,9 +153,6 @@ fn run_ui_toml(config: &mut compiletest::Config) {
 }
 
 fn run_ui_cargo(config: &mut compiletest::Config) {
-    if cargo::is_rustc_test_suite() {
-        return;
-    }
     fn run_tests(
         config: &compiletest::Config,
         filter: &Option<String>,