Rollup of 9 pull requests

.github/driver.sh

@@ -26,4 +26,16 @@ unset CARGO_MANIFEST_DIR
 sed -e "s,tests/ui,\$DIR," -e "/= help/d" cstring.stderr > normalized.stderr
 diff normalized.stderr tests/ui/cstring.stderr
 
+
+# make sure "clippy-driver --rustc --arg" and "rustc --arg" behave the same
+SYSROOT=`rustc --print sysroot`
+diff <(LD_LIBRARY_PATH=${SYSROOT}/lib ./target/debug/clippy-driver --rustc --version --verbose) <(rustc --version --verbose)
+
+
+echo "fn main() {}" > target/driver_test.rs
+# we can't run 2 rustcs on the same file at the same time
+CLIPPY=`LD_LIBRARY_PATH=${SYSROOT}/lib ./target/debug/clippy-driver ./target/driver_test.rs --rustc`
+RUSTC=`rustc ./target/driver_test.rs`
+diff <($CLIPPY) <($RUSTC)
+
 # TODO: CLIPPY_CONF_DIR / CARGO_MANIFEST_DIR

clippy_lints/src/consts.rs

@@ -396,7 +396,7 @@ impl<'c, 'cc> ConstEvalLateContext<'c, 'cc> {
         let l = self.expr(left)?;
         let r = self.expr(right);
         match (l, r) {
-            (Constant::Int(l), Some(Constant::Int(r))) => match self.tables.expr_ty(left).kind {
+            (Constant::Int(l), Some(Constant::Int(r))) => match self.tables.expr_ty_opt(left)?.kind {
                 ty::Int(ity) => {
                     let l = sext(self.lcx.tcx, l, ity);
                     let r = sext(self.lcx.tcx, r, ity);

clippy_lints/src/let_underscore.rs

@@ -35,7 +35,7 @@ declare_clippy_lint! {
     /// **What it does:** Checks for `let _ = sync_lock`
     ///
     /// **Why is this bad?** This statement immediately drops the lock instead of
-    /// extending it's lifetime to the end of the scope, which is often not intended.
+    /// extending its lifetime to the end of the scope, which is often not intended.
     /// To extend lock lifetime to the end of the scope, use an underscore-prefixed
     /// name instead (i.e. _lock). If you want to explicitly drop the lock,
     /// `std::mem::drop` conveys your intention better and is less error-prone.

clippy_lints/src/lib.rs

@@ -1,19 +1,22 @@
 // error-pattern:cargo-clippy
 
 #![feature(bindings_after_at)]
-#![feature(box_syntax)]
 #![feature(box_patterns)]
+#![feature(box_syntax)]
+#![feature(concat_idents)]
+#![feature(crate_visibility_modifier)]
+#![feature(drain_filter)]
 #![feature(or_patterns)]
 #![feature(rustc_private)]
 #![feature(stmt_expr_attributes)]
-#![allow(clippy::missing_docs_in_private_items, clippy::must_use_candidate)]
 #![recursion_limit = "512"]
-#![warn(rust_2018_idioms, trivial_casts, trivial_numeric_casts)]
-#![deny(rustc::internal)]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
-#![feature(crate_visibility_modifier)]
-#![feature(concat_idents)]
-#![feature(drain_filter)]
+#![allow(clippy::missing_docs_in_private_items, clippy::must_use_candidate)]
+#![warn(trivial_casts, trivial_numeric_casts)]
+// warn on lints, that are included in `rust-lang/rust`s bootstrap
+#![warn(rust_2018_idioms, unused_lifetimes)]
+// warn on rustc internal lints
+#![deny(rustc::internal)]
 
 // FIXME: switch to something more ergonomic here, once available.
 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
@@ -1187,6 +1190,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&types::OPTION_OPTION),
         LintId::of(&unicode::NON_ASCII_LITERAL),
         LintId::of(&unicode::UNICODE_NOT_NFC),
+        LintId::of(&unnested_or_patterns::UNNESTED_OR_PATTERNS),
         LintId::of(&unused_self::UNUSED_SELF),
         LintId::of(&wildcard_imports::ENUM_GLOB_USE),
         LintId::of(&wildcard_imports::WILDCARD_IMPORTS),
@@ -1440,7 +1444,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&unnamed_address::FN_ADDRESS_COMPARISONS),
         LintId::of(&unnamed_address::VTABLE_ADDRESS_COMPARISONS),
         LintId::of(&unnecessary_sort_by::UNNECESSARY_SORT_BY),
-        LintId::of(&unnested_or_patterns::UNNESTED_OR_PATTERNS),
         LintId::of(&unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME),
         LintId::of(&unused_io_amount::UNUSED_IO_AMOUNT),
         LintId::of(&unwrap::PANICKING_UNWRAP),
@@ -1624,7 +1627,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&types::UNNECESSARY_CAST),
         LintId::of(&types::VEC_BOX),
         LintId::of(&unnecessary_sort_by::UNNECESSARY_SORT_BY),
-        LintId::of(&unnested_or_patterns::UNNESTED_OR_PATTERNS),
         LintId::of(&unwrap::UNNECESSARY_UNWRAP),
         LintId::of(&useless_conversion::USELESS_CONVERSION),
         LintId::of(&zero_div_zero::ZERO_DIVIDED_BY_ZERO),

clippy_lints/src/loops.rs

@@ -1497,7 +1497,7 @@ struct MutatePairDelegate<'a, 'tcx> {
     span_high: Option<Span>,
 }
 
-impl<'a, 'tcx> Delegate<'tcx> for MutatePairDelegate<'a, 'tcx> {
+impl<'tcx> Delegate<'tcx> for MutatePairDelegate<'_, 'tcx> {
     fn consume(&mut self, _: &PlaceWithHirId<'tcx>, _: ConsumeMode) {}
 
     fn borrow(&mut self, cmt: &PlaceWithHirId<'tcx>, bk: ty::BorrowKind) {
@@ -1525,7 +1525,7 @@ impl<'a, 'tcx> Delegate<'tcx> for MutatePairDelegate<'a, 'tcx> {
     }
 }
 
-impl<'a, 'tcx> MutatePairDelegate<'a, 'tcx> {
+impl MutatePairDelegate<'_, '_> {
     fn mutation_span(&self) -> (Option<Span>, Option<Span>) {
         (self.span_low, self.span_high)
     }
@@ -2292,7 +2292,7 @@ struct HasBreakOrReturnVisitor {
     has_break_or_return: bool,
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for HasBreakOrReturnVisitor {
+impl<'tcx> Visitor<'tcx> for HasBreakOrReturnVisitor {
     type Map = Map<'tcx>;
 
     fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {

clippy_lints/src/new_without_default.rs

@@ -33,7 +33,7 @@ declare_clippy_lint! {
     /// }
     /// ```
     ///
-    /// To fix the lint, and a `Default` implementation that delegates to `new`:
+    /// To fix the lint, add a `Default` implementation that delegates to `new`:
     ///
     /// ```ignore
     /// struct Foo(Bar);

clippy_lints/src/redundant_pattern_matching.rs

@@ -1,10 +1,13 @@
-use crate::utils::{match_qpath, match_trait_method, paths, snippet, span_lint_and_then};
+use crate::utils::{in_constant, match_qpath, match_trait_method, paths, snippet, span_lint_and_then};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::{Arm, Expr, ExprKind, MatchSource, PatKind, QPath};
+use rustc_hir::{Arm, Expr, ExprKind, HirId, MatchSource, PatKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty;
+use rustc_mir::const_eval::is_const_fn;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Symbol;
 
 declare_clippy_lint! {
     /// **What it does:** Lint for redundant pattern matching over `Result` or
@@ -64,26 +67,37 @@ fn find_sugg_for_if_let<'a, 'tcx>(
     arms: &[Arm<'_>],
     keyword: &'static str,
 ) {
+    fn find_suggestion(cx: &LateContext<'_, '_>, hir_id: HirId, path: &QPath<'_>) -> Option<&'static str> {
+        if match_qpath(path, &paths::RESULT_OK) && can_suggest(cx, hir_id, sym!(result_type), "is_ok") {
+            return Some("is_ok()");
+        }
+        if match_qpath(path, &paths::RESULT_ERR) && can_suggest(cx, hir_id, sym!(result_type), "is_err") {
+            return Some("is_err()");
+        }
+        if match_qpath(path, &paths::OPTION_SOME) && can_suggest(cx, hir_id, sym!(option_type), "is_some") {
+            return Some("is_some()");
+        }
+        if match_qpath(path, &paths::OPTION_NONE) && can_suggest(cx, hir_id, sym!(option_type), "is_none") {
+            return Some("is_none()");
+        }
+        None
+    }
+
+    let hir_id = expr.hir_id;
     let good_method = match arms[0].pat.kind {
         PatKind::TupleStruct(ref path, ref patterns, _) if patterns.len() == 1 => {
             if let PatKind::Wild = patterns[0].kind {
-                if match_qpath(path, &paths::RESULT_OK) {
-                    "is_ok()"
-                } else if match_qpath(path, &paths::RESULT_ERR) {
-                    "is_err()"
-                } else if match_qpath(path, &paths::OPTION_SOME) {
-                    "is_some()"
-                } else {
-                    return;
-                }
+                find_suggestion(cx, hir_id, path)
             } else {
-                return;
+                None
             }
         },
-
-        PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
-
-        _ => return,
+        PatKind::Path(ref path) => find_suggestion(cx, hir_id, path),
+        _ => None,
+    };
+    let good_method = match good_method {
+        Some(method) => method,
+        None => return,
     };
 
     // check that `while_let_on_iterator` lint does not trigger
@@ -128,6 +142,7 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_
     if arms.len() == 2 {
         let node_pair = (&arms[0].pat.kind, &arms[1].pat.kind);
 
+        let hir_id = expr.hir_id;
         let found_good_method = match node_pair {
             (
                 PatKind::TupleStruct(ref path_left, ref patterns_left, _),
@@ -142,6 +157,8 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_
                         &paths::RESULT_ERR,
                         "is_ok()",
                         "is_err()",
+                        || can_suggest(cx, hir_id, sym!(result_type), "is_ok"),
+                        || can_suggest(cx, hir_id, sym!(result_type), "is_err"),
                     )
                 } else {
                     None
@@ -160,6 +177,8 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_
                         &paths::OPTION_NONE,
                         "is_some()",
                         "is_none()",
+                        || can_suggest(cx, hir_id, sym!(option_type), "is_some"),
+                        || can_suggest(cx, hir_id, sym!(option_type), "is_none"),
                     )
                 } else {
                     None
@@ -188,6 +207,7 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_
     }
 }
 
+#[allow(clippy::too_many_arguments)]
 fn find_good_method_for_match<'a>(
     arms: &[Arm<'_>],
     path_left: &QPath<'_>,
@@ -196,6 +216,8 @@ fn find_good_method_for_match<'a>(
     expected_right: &[&str],
     should_be_left: &'a str,
     should_be_right: &'a str,
+    can_suggest_left: impl Fn() -> bool,
+    can_suggest_right: impl Fn() -> bool,
 ) -> Option<&'a str> {
     let body_node_pair = if match_qpath(path_left, expected_left) && match_qpath(path_right, expected_right) {
         (&(*arms[0].body).kind, &(*arms[1].body).kind)
@@ -207,10 +229,32 @@ fn find_good_method_for_match<'a>(
 
     match body_node_pair {
         (ExprKind::Lit(ref lit_left), ExprKind::Lit(ref lit_right)) => match (&lit_left.node, &lit_right.node) {
-            (LitKind::Bool(true), LitKind::Bool(false)) => Some(should_be_left),
-            (LitKind::Bool(false), LitKind::Bool(true)) => Some(should_be_right),
+            (LitKind::Bool(true), LitKind::Bool(false)) if can_suggest_left() => Some(should_be_left),
+            (LitKind::Bool(false), LitKind::Bool(true)) if can_suggest_right() => Some(should_be_right),
             _ => None,
         },
         _ => None,
     }
 }
+
+fn can_suggest(cx: &LateContext<'_, '_>, hir_id: HirId, diag_item: Symbol, name: &str) -> bool {
+    if !in_constant(cx, hir_id) {
+        return true;
+    }
+
+    // Avoid suggesting calls to non-`const fn`s in const contexts, see #5697.
+    cx.tcx
+        .get_diagnostic_item(diag_item)
+        .and_then(|def_id| {
+            cx.tcx.inherent_impls(def_id).iter().find_map(|imp| {
+                cx.tcx
+                    .associated_items(*imp)
+                    .in_definition_order()
+                    .find_map(|item| match item.kind {
+                        ty::AssocKind::Fn if item.ident.name.as_str() == name => Some(item.def_id),
+                        _ => None,
+                    })
+            })
+        })
+        .map_or(false, |def_id| is_const_fn(cx.tcx, def_id))
+}

clippy_lints/src/suspicious_trait_impl.rs

@@ -184,7 +184,7 @@ struct BinaryExprVisitor {
     in_binary_expr: bool,
 }
 
-impl<'a, 'tcx> Visitor<'tcx> for BinaryExprVisitor {
+impl<'tcx> Visitor<'tcx> for BinaryExprVisitor {
     type Map = Map<'tcx>;
 
     fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {

clippy_lints/src/trivially_copy_pass_by_ref.rs

@@ -58,7 +58,7 @@ pub struct TriviallyCopyPassByRef {
     limit: u64,
 }
 
-impl<'a, 'tcx> TriviallyCopyPassByRef {
+impl<'tcx> TriviallyCopyPassByRef {
     pub fn new(limit: Option<u64>, target: &SessionConfig) -> Self {
         let limit = limit.unwrap_or_else(|| {
             let bit_width = u64::from(target.ptr_width);

clippy_lints/src/unnested_or_patterns.rs

@@ -45,7 +45,7 @@ declare_clippy_lint! {
     /// }
     /// ```
     pub UNNESTED_OR_PATTERNS,
-    complexity,
+    pedantic,
     "unnested or-patterns, e.g., `Foo(Bar) | Foo(Baz) instead of `Foo(Bar | Baz)`"
 }
 

clippy_lints/src/utils/conf.rs

@@ -106,8 +106,8 @@ macro_rules! define_Conf {
 
 pub use self::helpers::Conf;
 define_Conf! {
-    /// Lint: BLACKLISTED_NAME. The list of blacklisted names to lint about
-    (blacklisted_names, "blacklisted_names": Vec<String>, ["foo", "bar", "baz", "quux"].iter().map(ToString::to_string).collect()),
+    /// Lint: BLACKLISTED_NAME. The list of blacklisted names to lint about. NB: `bar` is not here since it has legitimate uses
+    (blacklisted_names, "blacklisted_names": Vec<String>, ["foo", "baz", "quux"].iter().map(ToString::to_string).collect()),
     /// Lint: COGNITIVE_COMPLEXITY. The maximum cognitive complexity a function can have
     (cognitive_complexity_threshold, "cognitive_complexity_threshold": u64, 25),
     /// DEPRECATED LINT: CYCLOMATIC_COMPLEXITY. Use the Cognitive Complexity lint instead.

clippy_lints/src/utils/sugg.rs

@@ -509,7 +509,7 @@ fn indentation<T: LintContext>(cx: &T, span: Span) -> Option<String> {
 }
 
 /// Convenience extension trait for `DiagnosticBuilder`.
-pub trait DiagnosticBuilderExt<'a, T: LintContext> {
+pub trait DiagnosticBuilderExt<T: LintContext> {
     /// Suggests to add an attribute to an item.
     ///
     /// Correctly handles indentation of the attribute and item.
@@ -556,7 +556,7 @@ pub trait DiagnosticBuilderExt<'a, T: LintContext> {
     fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability);
 }
 
-impl<'a, 'b, 'c, T: LintContext> DiagnosticBuilderExt<'c, T> for rustc_errors::DiagnosticBuilder<'b> {
+impl<T: LintContext> DiagnosticBuilderExt<T> for rustc_errors::DiagnosticBuilder<'_> {
     fn suggest_item_with_attr<D: Display + ?Sized>(
         &mut self,
         cx: &T,

clippy_lints/src/wildcard_imports.rs

@@ -36,7 +36,7 @@ declare_clippy_lint! {
 declare_clippy_lint! {
     /// **What it does:** Checks for wildcard imports `use _::*`.
     ///
-    /// **Why is this bad?** wildcard imports can polute the namespace. This is especially bad if
+    /// **Why is this bad?** wildcard imports can pollute the namespace. This is especially bad if
     /// you try to import something through a wildcard, that already has been imported by name from
     /// a different source:
     ///