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

Author: flip1995

CHANGELOG.md

@@ -4946,6 +4946,7 @@ Released 2018-09-13
 [`blanket_clippy_restriction_lints`]: https://rust-lang.github.io/rust-clippy/master/index.html#blanket_clippy_restriction_lints
 [`block_in_if_condition_expr`]: https://rust-lang.github.io/rust-clippy/master/index.html#block_in_if_condition_expr
 [`block_in_if_condition_stmt`]: https://rust-lang.github.io/rust-clippy/master/index.html#block_in_if_condition_stmt
+[`blocks_in_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions
 [`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions
 [`bool_assert_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_assert_comparison
 [`bool_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_comparison
@@ -5462,6 +5463,7 @@ Released 2018-09-13
 [`ref_patterns`]: https://rust-lang.github.io/rust-clippy/master/index.html#ref_patterns
 [`regex_macro`]: https://rust-lang.github.io/rust-clippy/master/index.html#regex_macro
 [`repeat_once`]: https://rust-lang.github.io/rust-clippy/master/index.html#repeat_once
+[`repeat_vec_with_capacity`]: https://rust-lang.github.io/rust-clippy/master/index.html#repeat_vec_with_capacity
 [`replace_consts`]: https://rust-lang.github.io/rust-clippy/master/index.html#replace_consts
 [`reserve_after_initialization`]: https://rust-lang.github.io/rust-clippy/master/index.html#reserve_after_initialization
 [`rest_pat_in_fully_bound_structs`]: https://rust-lang.github.io/rust-clippy/master/index.html#rest_pat_in_fully_bound_structs

clippy_lints/src/blocks_in_conditions.rs

@@ -0,0 +1,137 @@
+use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
+use clippy_utils::source::snippet_block_with_applicability;
+use clippy_utils::ty::implements_trait;
+use clippy_utils::visitors::{for_each_expr, Descend};
+use clippy_utils::{get_parent_expr, higher};
+use core::ops::ControlFlow;
+use rustc_errors::Applicability;
+use rustc_hir::{BlockCheckMode, Expr, ExprKind, MatchSource};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_session::declare_lint_pass;
+use rustc_span::sym;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for `if` conditions that use blocks containing an
+    /// expression, statements or conditions that use closures with blocks.
+    ///
+    /// ### Why is this bad?
+    /// Style, using blocks in the condition makes it hard to read.
+    ///
+    /// ### Examples
+    /// ```no_run
+    /// # fn somefunc() -> bool { true };
+    /// if { true } { /* ... */ }
+    ///
+    /// if { let x = somefunc(); x } { /* ... */ }
+    /// ```
+    ///
+    /// Use instead:
+    /// ```no_run
+    /// # fn somefunc() -> bool { true };
+    /// if true { /* ... */ }
+    ///
+    /// let res = { let x = somefunc(); x };
+    /// if res { /* ... */ }
+    /// ```
+    #[clippy::version = "1.45.0"]
+    pub BLOCKS_IN_CONDITIONS,
+    style,
+    "useless or complex blocks that can be eliminated in conditions"
+}
+
+declare_lint_pass!(BlocksInConditions => [BLOCKS_IN_CONDITIONS]);
+
+const BRACED_EXPR_MESSAGE: &str = "omit braces around single expression condition";
+
+impl<'tcx> LateLintPass<'tcx> for BlocksInConditions {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if in_external_macro(cx.sess(), expr.span) {
+            return;
+        }
+
+        let Some((cond, keyword, desc)) = higher::If::hir(expr)
+            .map(|hif| (hif.cond, "if", "an `if` condition"))
+            .or(if let ExprKind::Match(match_ex, _, MatchSource::Normal) = expr.kind {
+                Some((match_ex, "match", "a `match` scrutinee"))
+            } else {
+                None
+            })
+        else {
+            return;
+        };
+        let complex_block_message = &format!(
+            "in {desc}, avoid complex blocks or closures with blocks; \
+            instead, move the block or closure higher and bind it with a `let`",
+        );
+
+        if let ExprKind::Block(block, _) = &cond.kind {
+            if block.rules == BlockCheckMode::DefaultBlock {
+                if block.stmts.is_empty() {
+                    if let Some(ex) = &block.expr {
+                        // don't dig into the expression here, just suggest that they remove
+                        // the block
+                        if expr.span.from_expansion() || ex.span.from_expansion() {
+                            return;
+                        }
+                        let mut applicability = Applicability::MachineApplicable;
+                        span_lint_and_sugg(
+                            cx,
+                            BLOCKS_IN_CONDITIONS,
+                            cond.span,
+                            BRACED_EXPR_MESSAGE,
+                            "try",
+                            snippet_block_with_applicability(cx, ex.span, "..", Some(expr.span), &mut applicability)
+                                .to_string(),
+                            applicability,
+                        );
+                    }
+                } else {
+                    let span = block.expr.as_ref().map_or_else(|| block.stmts[0].span, |e| e.span);
+                    if span.from_expansion() || expr.span.from_expansion() {
+                        return;
+                    }
+                    // move block higher
+                    let mut applicability = Applicability::MachineApplicable;
+                    span_lint_and_sugg(
+                        cx,
+                        BLOCKS_IN_CONDITIONS,
+                        expr.span.with_hi(cond.span.hi()),
+                        complex_block_message,
+                        "try",
+                        format!(
+                            "let res = {}; {keyword} res",
+                            snippet_block_with_applicability(cx, block.span, "..", Some(expr.span), &mut applicability),
+                        ),
+                        applicability,
+                    );
+                }
+            }
+        } else {
+            let _: Option<!> = for_each_expr(cond, |e| {
+                if let ExprKind::Closure(closure) = e.kind {
+                    // do not lint if the closure is called using an iterator (see #1141)
+                    if let Some(parent) = get_parent_expr(cx, e)
+                        && let ExprKind::MethodCall(_, self_arg, _, _) = &parent.kind
+                        && let caller = cx.typeck_results().expr_ty(self_arg)
+                        && let Some(iter_id) = cx.tcx.get_diagnostic_item(sym::Iterator)
+                        && implements_trait(cx, caller, iter_id, &[])
+                    {
+                        return ControlFlow::Continue(Descend::No);
+                    }
+
+                    let body = cx.tcx.hir().body(closure.body);
+                    let ex = &body.value;
+                    if let ExprKind::Block(block, _) = ex.kind {
+                        if !body.value.span.from_expansion() && !block.stmts.is_empty() {
+                            span_lint(cx, BLOCKS_IN_CONDITIONS, ex.span, complex_block_message);
+                            return ControlFlow::Continue(Descend::No);
+                        }
+                    }
+                }
+                ControlFlow::Continue(Descend::Yes)
+            });
+        }
+    }
+}

clippy_lints/src/blocks_in_if_conditions.rs

@@ -63,7 +63,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::await_holding_invalid::AWAIT_HOLDING_INVALID_TYPE_INFO,
     crate::await_holding_invalid::AWAIT_HOLDING_LOCK_INFO,
     crate::await_holding_invalid::AWAIT_HOLDING_REFCELL_REF_INFO,
-    crate::blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS_INFO,
+    crate::blocks_in_conditions::BLOCKS_IN_CONDITIONS_INFO,
     crate::bool_assert_comparison::BOOL_ASSERT_COMPARISON_INFO,
     crate::bool_to_int_with_if::BOOL_TO_INT_WITH_IF_INFO,
     crate::booleans::NONMINIMAL_BOOL_INFO,
@@ -598,6 +598,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::reference::DEREF_ADDROF_INFO,
     crate::regex::INVALID_REGEX_INFO,
     crate::regex::TRIVIAL_REGEX_INFO,
+    crate::repeat_vec_with_capacity::REPEAT_VEC_WITH_CAPACITY_INFO,
     crate::reserve_after_initialization::RESERVE_AFTER_INITIALIZATION_INFO,
     crate::return_self_not_must_use::RETURN_SELF_NOT_MUST_USE_INFO,
     crate::returns::LET_AND_RETURN_INFO,

clippy_lints/src/declared_lints.rs

@@ -74,7 +74,7 @@ mod assertions_on_result_states;
 mod async_yields_async;
 mod attrs;
 mod await_holding_invalid;
-mod blocks_in_if_conditions;
+mod blocks_in_conditions;
 mod bool_assert_comparison;
 mod bool_to_int_with_if;
 mod booleans;
@@ -289,6 +289,7 @@ mod ref_option_ref;
 mod ref_patterns;
 mod reference;
 mod regex;
+mod repeat_vec_with_capacity;
 mod reserve_after_initialization;
 mod return_self_not_must_use;
 mod returns;
@@ -653,7 +654,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     store.register_late_pass(|_| Box::<significant_drop_tightening::SignificantDropTightening<'_>>::default());
     store.register_late_pass(|_| Box::new(len_zero::LenZero));
     store.register_late_pass(|_| Box::new(attrs::Attributes));
-    store.register_late_pass(|_| Box::new(blocks_in_if_conditions::BlocksInIfConditions));
+    store.register_late_pass(|_| Box::new(blocks_in_conditions::BlocksInConditions));
     store.register_late_pass(|_| Box::new(unicode::Unicode));
     store.register_late_pass(|_| Box::new(uninit_vec::UninitVec));
     store.register_late_pass(|_| Box::new(unit_return_expecting_ord::UnitReturnExpectingOrd));
@@ -1069,6 +1070,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     store.register_late_pass(|_| Box::new(iter_without_into_iter::IterWithoutIntoIter));
     store.register_late_pass(|_| Box::new(iter_over_hash_type::IterOverHashType));
     store.register_late_pass(|_| Box::new(impl_hash_with_borrow_str_and_bytes::ImplHashWithBorrowStrBytes));
+    store.register_late_pass(|_| Box::new(repeat_vec_with_capacity::RepeatVecWithCapacity));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 

clippy_lints/src/lib.rs

@@ -36,7 +36,8 @@ struct PathAndSpan {
     span: Span,
 }
 
-/// `MacroRefData` includes the name of the macro.
+/// `MacroRefData` includes the name of the macro
+/// and the path from `SourceMap::span_to_filename`.
 #[derive(Debug, Clone)]
 pub struct MacroRefData {
     name: String,

clippy_lints/src/macro_use.rs

@@ -108,18 +108,16 @@ fn parse_call(cx: &LateContext<'_>, span: Span, func: &Expr<'_>, args: &[Expr<'_
 
     let arg_kind = &args[0].kind;
     if let ExprKind::Path(qpath) = &func.kind {
-        if let QPath::TypeRelative(_, _) = qpath {
-            // String::from(...) or String::try_from(...)
-            if let QPath::TypeRelative(ty, path_seg) = qpath
-                && [sym::from, sym::try_from].contains(&path_seg.ident.name)
-                && let TyKind::Path(qpath) = &ty.kind
-                && let QPath::Resolved(_, path) = qpath
-                && let [path_seg] = path.segments
-                && path_seg.ident.name == sym::String
-                && is_expr_kind_empty_str(arg_kind)
-            {
-                warn_then_suggest(cx, span);
-            }
+        // String::from(...) or String::try_from(...)
+        if let QPath::TypeRelative(ty, path_seg) = qpath
+            && [sym::from, sym::try_from].contains(&path_seg.ident.name)
+            && let TyKind::Path(qpath) = &ty.kind
+            && let QPath::Resolved(_, path) = qpath
+            && let [path_seg] = path.segments
+            && path_seg.ident.name == sym::String
+            && is_expr_kind_empty_str(arg_kind)
+        {
+            warn_then_suggest(cx, span);
         } else if let QPath::Resolved(_, path) = qpath {
             // From::from(...) or TryFrom::try_from(...)
             if let [path_seg1, path_seg2] = path.segments

clippy_lints/src/manual_string_new.rs

@@ -5,7 +5,8 @@ use clippy_utils::ty::implements_trait;
 use rustc_errors::Applicability;
 use rustc_hir::{Closure, Expr, ExprKind, Mutability, Param, Pat, PatKind, Path, PathSegment, QPath};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, GenericArgKind};
+use rustc_middle::ty;
+use rustc_middle::ty::GenericArgKind;
 use rustc_span::sym;
 use rustc_span::symbol::Ident;
 use std::iter;