Merge commit 'bf1c6f9871' into clippyup

clippy_lints/src/utils/eager_or_lazy.rs

@@ -82,7 +82,7 @@ fn identify_some_pure_patterns(expr: &Expr<'_>) -> bool {
 /// Identify some potentially computationally expensive patterns.
 /// This function is named so to stress that its implementation is non-exhaustive.
 /// It returns FNs and FPs.
-fn identify_some_potentially_expensive_patterns<'a, 'tcx>(cx: &'a LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
+fn identify_some_potentially_expensive_patterns<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
     // Searches an expression for method calls or function calls that aren't ctors
     struct FunCallFinder<'a, 'tcx> {
         cx: &'a LateContext<'tcx>,

clippy_lints/src/utils/higher.rs

@@ -7,6 +7,7 @@ use crate::utils::{is_expn_of, match_def_path, paths};
 use if_chain::if_chain;
 use rustc_ast::ast;
 use rustc_hir as hir;
+use rustc_hir::{BorrowKind, Expr, ExprKind, StmtKind, UnOp};
 use rustc_lint::LateContext;
 
 /// Converts a hir binary operator to the corresponding `ast` type.
@@ -241,3 +242,56 @@ pub fn vec_macro<'e>(cx: &LateContext<'_>, expr: &'e hir::Expr<'_>) -> Option<Ve
 
     None
 }
+
+/// Extract args from an assert-like macro.
+/// Currently working with:
+/// - `assert!`, `assert_eq!` and `assert_ne!`
+/// - `debug_assert!`, `debug_assert_eq!` and `debug_assert_ne!`
+/// For example:
+/// `assert!(expr)` will return Some([expr])
+/// `debug_assert_eq!(a, b)` will return Some([a, b])
+pub fn extract_assert_macro_args<'tcx>(e: &'tcx Expr<'tcx>) -> Option<Vec<&'tcx Expr<'tcx>>> {
+    /// Try to match the AST for a pattern that contains a match, for example when two args are
+    /// compared
+    fn ast_matchblock(matchblock_expr: &'tcx Expr<'tcx>) -> Option<Vec<&Expr<'_>>> {
+        if_chain! {
+            if let ExprKind::Match(ref headerexpr, _, _) = &matchblock_expr.kind;
+            if let ExprKind::Tup([lhs, rhs]) = &headerexpr.kind;
+            if let ExprKind::AddrOf(BorrowKind::Ref, _, lhs) = lhs.kind;
+            if let ExprKind::AddrOf(BorrowKind::Ref, _, rhs) = rhs.kind;
+            then {
+                return Some(vec![lhs, rhs]);
+            }
+        }
+        None
+    }
+
+    if let ExprKind::Block(ref block, _) = e.kind {
+        if block.stmts.len() == 1 {
+            if let StmtKind::Semi(ref matchexpr) = block.stmts[0].kind {
+                // macros with unique arg: `{debug_}assert!` (e.g., `debug_assert!(some_condition)`)
+                if_chain! {
+                    if let ExprKind::Match(ref ifclause, _, _) = matchexpr.kind;
+                    if let ExprKind::DropTemps(ref droptmp) = ifclause.kind;
+                    if let ExprKind::Unary(UnOp::UnNot, condition) = droptmp.kind;
+                    then {
+                        return Some(vec![condition]);
+                    }
+                }
+
+                // debug macros with two args: `debug_assert_{ne, eq}` (e.g., `assert_ne!(a, b)`)
+                if_chain! {
+                    if let ExprKind::Block(ref matchblock,_) = matchexpr.kind;
+                    if let Some(ref matchblock_expr) = matchblock.expr;
+                    then {
+                        return ast_matchblock(matchblock_expr);
+                    }
+                }
+            }
+        } else if let Some(matchblock_expr) = block.expr {
+            // macros with two args: `assert_{ne, eq}` (e.g., `assert_ne!(a, b)`)
+            return ast_matchblock(&matchblock_expr);
+        }
+    }
+    None
+}

clippy_lints/src/utils/mod.rs

@@ -708,7 +708,7 @@ fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>,
 }
 
 /// Gets the parent expression, if any –- this is useful to constrain a lint.
-pub fn get_parent_expr<'c>(cx: &'c LateContext<'_>, e: &Expr<'_>) -> Option<&'c Expr<'c>> {
+pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     let map = &cx.tcx.hir();
     let hir_id = e.hir_id;
     let parent_id = map.get_parent_node(hir_id);

clippy_lints/src/utils/sugg.rs

@@ -13,8 +13,10 @@ use rustc_span::{BytePos, Pos};
 use std::borrow::Cow;
 use std::convert::TryInto;
 use std::fmt::Display;
+use std::ops::{Add, Neg, Not, Sub};
 
 /// A helper type to build suggestion correctly handling parenthesis.
+#[derive(Clone, PartialEq)]
 pub enum Sugg<'a> {
     /// An expression that never needs parenthesis such as `1337` or `[0; 42]`.
     NonParen(Cow<'a, str>),
@@ -25,8 +27,12 @@ pub enum Sugg<'a> {
     BinOp(AssocOp, Cow<'a, str>),
 }
 
+/// Literal constant `0`, for convenience.
+pub const ZERO: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("0"));
 /// Literal constant `1`, for convenience.
 pub const ONE: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("1"));
+/// a constant represents an empty string, for convenience.
+pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed(""));
 
 impl Display for Sugg<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
@@ -269,21 +275,60 @@ impl<'a> Sugg<'a> {
     }
 }
 
-impl<'a, 'b> std::ops::Add<Sugg<'b>> for Sugg<'a> {
+// Copied from the rust standart library, and then edited
+macro_rules! forward_binop_impls_to_ref {
+    (impl $imp:ident, $method:ident for $t:ty, type Output = $o:ty) => {
+        impl $imp<$t> for &$t {
+            type Output = $o;
+
+            fn $method(self, other: $t) -> $o {
+                $imp::$method(self, &other)
+            }
+        }
+
+        impl $imp<&$t> for $t {
+            type Output = $o;
+
+            fn $method(self, other: &$t) -> $o {
+                $imp::$method(&self, other)
+            }
+        }
+
+        impl $imp for $t {
+            type Output = $o;
+
+            fn $method(self, other: $t) -> $o {
+                $imp::$method(&self, &other)
+            }
+        }
+    };
+}
+
+impl Add for &Sugg<'_> {
     type Output = Sugg<'static>;
-    fn add(self, rhs: Sugg<'b>) -> Sugg<'static> {
-        make_binop(ast::BinOpKind::Add, &self, &rhs)
+    fn add(self, rhs: &Sugg<'_>) -> Sugg<'static> {
+        make_binop(ast::BinOpKind::Add, self, rhs)
     }
 }
 
-impl<'a, 'b> std::ops::Sub<Sugg<'b>> for Sugg<'a> {
+impl Sub for &Sugg<'_> {
     type Output = Sugg<'static>;
-    fn sub(self, rhs: Sugg<'b>) -> Sugg<'static> {
-        make_binop(ast::BinOpKind::Sub, &self, &rhs)
+    fn sub(self, rhs: &Sugg<'_>) -> Sugg<'static> {
+        make_binop(ast::BinOpKind::Sub, self, rhs)
     }
 }
 
-impl<'a> std::ops::Not for Sugg<'a> {
+forward_binop_impls_to_ref!(impl Add, add for Sugg<'_>, type Output = Sugg<'static>);
+forward_binop_impls_to_ref!(impl Sub, sub for Sugg<'_>, type Output = Sugg<'static>);
+
+impl Neg for Sugg<'_> {
+    type Output = Sugg<'static>;
+    fn neg(self) -> Sugg<'static> {
+        make_unop("-", self)
+    }
+}
+
+impl Not for Sugg<'_> {
     type Output = Sugg<'static>;
     fn not(self) -> Sugg<'static> {
         make_unop("!", self)

clippy_lints/src/utils/usage.rs

@@ -1,10 +1,11 @@
+use crate::utils;
 use crate::utils::match_var;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::intravisit;
 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
-use rustc_hir::{Expr, HirId, Path};
+use rustc_hir::{Expr, ExprKind, HirId, Path};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_lint::LateContext;
 use rustc_middle::hir::map::Map;
@@ -174,3 +175,50 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for BindingUsageFinder<'a, 'tcx> {
         intravisit::NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
     }
 }
+
+struct ReturnBreakContinueMacroVisitor {
+    seen_return_break_continue: bool,
+}
+
+impl ReturnBreakContinueMacroVisitor {
+    fn new() -> ReturnBreakContinueMacroVisitor {
+        ReturnBreakContinueMacroVisitor {
+            seen_return_break_continue: false,
+        }
+    }
+}
+
+impl<'tcx> Visitor<'tcx> for ReturnBreakContinueMacroVisitor {
+    type Map = Map<'tcx>;
+    fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
+        NestedVisitorMap::None
+    }
+
+    fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
+        if self.seen_return_break_continue {
+            // No need to look farther if we've already seen one of them
+            return;
+        }
+        match &ex.kind {
+            ExprKind::Ret(..) | ExprKind::Break(..) | ExprKind::Continue(..) => {
+                self.seen_return_break_continue = true;
+            },
+            // Something special could be done here to handle while or for loop
+            // desugaring, as this will detect a break if there's a while loop
+            // or a for loop inside the expression.
+            _ => {
+                if utils::in_macro(ex.span) {
+                    self.seen_return_break_continue = true;
+                } else {
+                    rustc_hir::intravisit::walk_expr(self, ex);
+                }
+            },
+        }
+    }
+}
+
+pub fn contains_return_break_continue_macro(expression: &Expr<'_>) -> bool {
+    let mut recursive_visitor = ReturnBreakContinueMacroVisitor::new();
+    recursive_visitor.visit_expr(expression);
+    recursive_visitor.seen_return_break_continue
+}