Merge commit '61eb38aeda6cb54b93b872bf503d70084c4d621c' into clippyup

6 files changed, 117 insertions, 49 deletions

diff --git a/src/tools/clippy/clippy_utils/Cargo.toml b/src/tools/clippy/clippy_utils/Cargo.toml
index 93ed3b18400..6ede9011208 100644
--- a/src/tools/clippy/clippy_utils/Cargo.toml
+++ b/src/tools/clippy/clippy_utils/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "clippy_utils"
-version = "0.1.54"
+version = "0.1.55"
 authors = ["The Rust Clippy Developers"]
 edition = "2018"
 publish = false
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index 90c034bd02a..30c2260d15c 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -47,9 +47,14 @@ pub fn eq_pat(l: &Pat, r: &Pat) -> bool {
         | (Ref(l, Mutability::Mut), Ref(r, Mutability::Mut)) => eq_pat(l, r),
         (Tuple(l), Tuple(r)) | (Slice(l), Slice(r)) => over(l, r, |l, r| eq_pat(l, r)),
         (Path(lq, lp), Path(rq, rp)) => both(lq, rq, |l, r| eq_qself(l, r)) && eq_path(lp, rp),
-        (TupleStruct(lqself, lp, lfs), TupleStruct(rqself, rp, rfs)) => eq_maybe_qself(lqself, rqself) && eq_path(lp, rp) && over(lfs, rfs, |l, r| eq_pat(l, r)),
+        (TupleStruct(lqself, lp, lfs), TupleStruct(rqself, rp, rfs)) => {
+            eq_maybe_qself(lqself, rqself) && eq_path(lp, rp) && over(lfs, rfs, |l, r| eq_pat(l, r))
+        },
         (Struct(lqself, lp, lfs, lr), Struct(rqself, rp, rfs, rr)) => {
-            lr == rr && eq_maybe_qself(lqself, rqself) &&eq_path(lp, rp) && unordered_over(lfs, rfs, |lf, rf| eq_field_pat(lf, rf))
+            lr == rr
+                && eq_maybe_qself(lqself, rqself)
+                && eq_path(lp, rp)
+                && unordered_over(lfs, rfs, |lf, rf| eq_field_pat(lf, rf))
         },
         (Or(ls), Or(rs)) => unordered_over(ls, rs, |l, r| eq_pat(l, r)),
         (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
@@ -82,7 +87,7 @@ pub fn eq_maybe_qself(l: &Option<QSelf>, r: &Option<QSelf>) -> bool {
     match (l, r) {
         (Some(l), Some(r)) => eq_qself(l, r),
         (None, None) => true,
-        _ => false
+        _ => false,
     }
 }
 
diff --git a/src/tools/clippy/clippy_utils/src/attrs.rs b/src/tools/clippy/clippy_utils/src/attrs.rs
index 0318c483959..c19b558cd8c 100644
--- a/src/tools/clippy/clippy_utils/src/attrs.rs
+++ b/src/tools/clippy/clippy_utils/src/attrs.rs
@@ -157,3 +157,8 @@ pub fn is_doc_hidden(attrs: &[ast::Attribute]) -> bool {
         .filter_map(ast::Attribute::meta_item_list)
         .any(|l| attr::list_contains_name(&l, sym::hidden))
 }
+
+/// Return true if the attributes contain `#[unstable]`
+pub fn is_unstable(attrs: &[ast::Attribute]) -> bool {
+    attrs.iter().any(|attr| attr.has_name(sym::unstable))
+}
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index 0d7fdeeb920..15c27d1a996 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -1,6 +1,6 @@
 #![allow(clippy::float_cmp)]
 
-use crate::{clip, sext, unsext};
+use crate::{clip, is_direct_expn_of, sext, unsext};
 use if_chain::if_chain;
 use rustc_ast::ast::{self, LitFloatType, LitKind};
 use rustc_data_structures::sync::Lrc;
@@ -230,7 +230,13 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
         match e.kind {
             ExprKind::Path(ref qpath) => self.fetch_path(qpath, e.hir_id, self.typeck_results.expr_ty(e)),
             ExprKind::Block(block, _) => self.block(block),
-            ExprKind::Lit(ref lit) => Some(lit_to_constant(&lit.node, self.typeck_results.expr_ty_opt(e))),
+            ExprKind::Lit(ref lit) => {
+                if is_direct_expn_of(e.span, "cfg").is_some() {
+                    None
+                } else {
+                    Some(lit_to_constant(&lit.node, self.typeck_results.expr_ty_opt(e)))
+                }
+            },
             ExprKind::Array(vec) => self.multi(vec).map(Constant::Vec),
             ExprKind::Tup(tup) => self.multi(tup).map(Constant::Tuple),
             ExprKind::Repeat(value, _) => {
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 769836aaf18..ef4854afc83 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -72,7 +72,7 @@ use rustc_hir::LangItem::{ResultErr, ResultOk};
 use rustc_hir::{
     def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
     ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path,
-    PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
+    PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind, UnOp,
 };
 use rustc_lint::{LateContext, Level, Lint, LintContext};
 use rustc_middle::hir::exports::Export;
@@ -326,16 +326,6 @@ pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol)
         .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
 }
 
-/// Checks if an expression references a variable of the given name.
-pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
-    if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
-        if let [p] = path.segments {
-            return p.ident.name == var;
-        }
-    }
-    false
-}
-
 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
     match *path {
         QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
@@ -707,16 +697,6 @@ pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
     }
 }
 
-/// Gets the name of a `Pat`, if any.
-pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
-    match pat.kind {
-        PatKind::Binding(.., ref spname, _) => Some(spname.name),
-        PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
-        PatKind::Box(p) | PatKind::Ref(p, _) => get_pat_name(&*p),
-        _ => None,
-    }
-}
-
 pub struct ContainsName {
     pub name: Symbol,
     pub result: bool,
@@ -861,14 +841,16 @@ pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Optio
     })
 }
 
-/// Gets the loop enclosing the given expression, if any.
-pub fn get_enclosing_loop(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
+/// Gets the loop or closure enclosing the given expression, if any.
+pub fn get_enclosing_loop_or_closure(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     let map = tcx.hir();
     for (_, node) in map.parent_iter(expr.hir_id) {
         match node {
             Node::Expr(
-                e @ Expr {
-                    kind: ExprKind::Loop(..),
+                e
+                @
+                Expr {
+                    kind: ExprKind::Loop(..) | ExprKind::Closure(..),
                     ..
                 },
             ) => return Some(e),
@@ -1399,6 +1381,55 @@ pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
 }
 
+/// Checks if an expression represents the identity function
+/// Only examines closures and `std::convert::identity`
+pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    /// Checks if a function's body represents the identity function. Looks for bodies of the form:
+    /// * `|x| x`
+    /// * `|x| return x`
+    /// * `|x| { return x }`
+    /// * `|x| { return x; }`
+    fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
+        let id = if_chain! {
+            if let [param] = func.params;
+            if let PatKind::Binding(_, id, _, _) = param.pat.kind;
+            then {
+                id
+            } else {
+                return false;
+            }
+        };
+
+        let mut expr = &func.value;
+        loop {
+            match expr.kind {
+                #[rustfmt::skip]
+                ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
+                | ExprKind::Ret(Some(e)) => expr = e,
+                #[rustfmt::skip]
+                ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
+                    if_chain! {
+                        if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
+                        if let ExprKind::Ret(Some(ret_val)) = e.kind;
+                        then {
+                            expr = ret_val;
+                        } else {
+                            return false;
+                        }
+                    }
+                },
+                _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
+            }
+        }
+    }
+
+    match expr.kind {
+        ExprKind::Closure(_, _, body_id, _, _) => is_body_identity_function(cx, cx.tcx.hir().body(body_id)),
+        ExprKind::Path(ref path) => is_qpath_def_path(cx, path, expr.hir_id, &paths::CONVERT_IDENTITY),
+        _ => false,
+    }
+}
+
 /// Gets the node where an expression is either used, or it's type is unified with another branch.
 pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
     let map = tcx.hir();
@@ -1654,6 +1685,19 @@ pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
     (e, count)
 }
 
+/// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
+/// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
+pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
+    loop {
+        match expr.kind {
+            ExprKind::AddrOf(_, _, e) => expr = e,
+            ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
+            _ => break,
+        }
+    }
+    expr
+}
+
 #[macro_export]
 macro_rules! unwrap_cargo_metadata {
     ($cx: ident, $lint: ident, $deps: expr) => {{
@@ -1683,3 +1727,15 @@ pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
         }
     }
 }
+
+/// Checks whether item either has `test` attribute applied, or
+/// is a module with `test` in its name.
+pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
+    if let Some(def_id) = tcx.hir().opt_local_def_id(item.hir_id()) {
+        if tcx.has_attr(def_id.to_def_id(), sym::test) {
+            return true;
+        }
+    }
+
+    matches!(item.kind, ItemKind::Mod(..)) && item.ident.name.as_str().contains("test")
+}
diff --git a/src/tools/clippy/clippy_utils/src/ptr.rs b/src/tools/clippy/clippy_utils/src/ptr.rs
index 791688cd194..8adb6915952 100644
--- a/src/tools/clippy/clippy_utils/src/ptr.rs
+++ b/src/tools/clippy/clippy_utils/src/ptr.rs
@@ -1,10 +1,10 @@
 use crate::source::snippet;
-use crate::{get_pat_name, match_var};
+use crate::{path_to_local_id, strip_pat_refs};
 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
-use rustc_hir::{Body, BodyId, Expr, ExprKind, Param};
+use rustc_hir::{Body, BodyId, Expr, ExprKind, HirId, PatKind};
 use rustc_lint::LateContext;
 use rustc_middle::hir::map::Map;
-use rustc_span::{Span, Symbol};
+use rustc_span::Span;
 use std::borrow::Cow;
 
 pub fn get_spans(
@@ -14,10 +14,11 @@ pub fn get_spans(
     replacements: &[(&'static str, &'static str)],
 ) -> Option<Vec<(Span, Cow<'static, str>)>> {
     if let Some(body) = opt_body_id.map(|id| cx.tcx.hir().body(id)) {
-        get_binding_name(&body.params[idx]).map_or_else(
-            || Some(vec![]),
-            |name| extract_clone_suggestions(cx, name, replacements, body),
-        )
+        if let PatKind::Binding(_, binding_id, _, _) = strip_pat_refs(body.params[idx].pat).kind {
+            extract_clone_suggestions(cx, binding_id, replacements, body)
+        } else {
+            Some(vec![])
+        }
     } else {
         Some(vec![])
     }
@@ -25,13 +26,13 @@ pub fn get_spans(
 
 fn extract_clone_suggestions<'tcx>(
     cx: &LateContext<'tcx>,
-    name: Symbol,
+    id: HirId,
     replace: &[(&'static str, &'static str)],
     body: &'tcx Body<'_>,
 ) -> Option<Vec<(Span, Cow<'static, str>)>> {
     let mut visitor = PtrCloneVisitor {
         cx,
-        name,
+        id,
         replace,
         spans: vec![],
         abort: false,
@@ -42,7 +43,7 @@ fn extract_clone_suggestions<'tcx>(
 
 struct PtrCloneVisitor<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
-    name: Symbol,
+    id: HirId,
     replace: &'a [(&'static str, &'static str)],
     spans: Vec<(Span, Cow<'static, str>)>,
     abort: bool,
@@ -55,16 +56,15 @@ impl<'a, 'tcx> Visitor<'tcx> for PtrCloneVisitor<'a, 'tcx> {
         if self.abort {
             return;
         }
-        if let ExprKind::MethodCall(seg, _, args, _) = expr.kind {
-            if args.len() == 1 && match_var(&args[0], self.name) {
+        if let ExprKind::MethodCall(seg, _, [recv], _) = expr.kind {
+            if path_to_local_id(recv, self.id) {
                 if seg.ident.name.as_str() == "capacity" {
                     self.abort = true;
                     return;
                 }
                 for &(fn_name, suffix) in self.replace {
                     if seg.ident.name.as_str() == fn_name {
-                        self.spans
-                            .push((expr.span, snippet(self.cx, args[0].span, "_") + suffix));
+                        self.spans.push((expr.span, snippet(self.cx, recv.span, "_") + suffix));
                         return;
                     }
                 }
@@ -77,7 +77,3 @@ impl<'a, 'tcx> Visitor<'tcx> for PtrCloneVisitor<'a, 'tcx> {
         NestedVisitorMap::None
     }
 }
-
-fn get_binding_name(arg: &Param<'_>) -> Option<Symbol> {
-    get_pat_name(arg.pat)
-}