Merge commit '3e7c6dec24' into clippyup

clippy_lints/src/utils/ast_utils.rs

@@ -110,8 +110,7 @@ pub fn eq_expr_opt(l: &Option<P<Expr>>, r: &Option<P<Expr>>) -> bool {
 pub fn eq_struct_rest(l: &StructRest, r: &StructRest) -> bool {
     match (l, r) {
         (StructRest::Base(lb), StructRest::Base(rb)) => eq_expr(lb, rb),
-        (StructRest::Rest(_), StructRest::Rest(_)) => true,
-        (StructRest::None, StructRest::None) => true,
+        (StructRest::Rest(_), StructRest::Rest(_)) | (StructRest::None, StructRest::None) => true,
         _ => false,
     }
 }

clippy_lints/src/utils/eager_or_lazy.rs

@@ -9,7 +9,7 @@
 //!  - or-fun-call
 //!  - option-if-let-else
 
-use crate::utils::is_ctor_or_promotable_const_function;
+use crate::utils::{is_ctor_or_promotable_const_function, is_type_diagnostic_item, match_type, paths};
 use rustc_hir::def::{DefKind, Res};
 
 use rustc_hir::intravisit;
@@ -96,6 +96,11 @@ fn identify_some_potentially_expensive_patterns<'tcx>(cx: &LateContext<'tcx>, ex
             let call_found = match &expr.kind {
                 // ignore enum and struct constructors
                 ExprKind::Call(..) => !is_ctor_or_promotable_const_function(self.cx, expr),
+                ExprKind::Index(obj, _) => {
+                    let ty = self.cx.typeck_results().expr_ty(obj);
+                    is_type_diagnostic_item(self.cx, ty, sym!(hashmap_type))
+                        || match_type(self.cx, ty, &paths::BTREEMAP)
+                },
                 ExprKind::MethodCall(..) => true,
                 _ => false,
             };

clippy_lints/src/utils/mod.rs

@@ -21,6 +21,7 @@ pub mod ptr;
 pub mod qualify_min_const_fn;
 pub mod sugg;
 pub mod usage;
+pub mod visitors;
 
 pub use self::attrs::*;
 pub use self::diagnostics::*;
@@ -468,6 +469,13 @@ pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
         .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
 }
 
+/// Returns `true` if the expression is in the program's `#[panic_handler]`.
+pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
+    let parent = cx.tcx.hir().get_parent_item(e.hir_id);
+    let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
+    Some(def_id) == cx.tcx.lang_items().panic_impl()
+}
+
 /// Gets the name of the item the expression is in, if available.
 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
     let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
@@ -659,6 +667,35 @@ pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
     snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
 }
 
+/// Returns the positon just before rarrow
+///
+/// ```rust,ignore
+/// fn into(self) -> () {}
+///              ^
+/// // in case of unformatted code
+/// fn into2(self)-> () {}
+///               ^
+/// fn into3(self)   -> () {}
+///               ^
+/// ```
+#[allow(clippy::needless_pass_by_value)]
+pub fn position_before_rarrow(s: String) -> Option<usize> {
+    s.rfind("->").map(|rpos| {
+        let mut rpos = rpos;
+        let chars: Vec<char> = s.chars().collect();
+        while rpos > 1 {
+            if let Some(c) = chars.get(rpos - 1) {
+                if c.is_whitespace() {
+                    rpos -= 1;
+                    continue;
+                }
+            }
+            break;
+        }
+        rpos
+    })
+}
+
 /// Extends the span to the beginning of the spans line, incl. whitespaces.
 ///
 /// ```rust,ignore

clippy_lints/src/utils/paths.rs

@@ -126,6 +126,7 @@ pub const STRING: [&str; 3] = ["alloc", "string", "String"];
 pub const STRING_AS_MUT_STR: [&str; 4] = ["alloc", "string", "String", "as_mut_str"];
 pub const STRING_AS_STR: [&str; 4] = ["alloc", "string", "String", "as_str"];
 pub const STR_ENDS_WITH: [&str; 4] = ["core", "str", "<impl str>", "ends_with"];
+pub const STR_FROM_UTF8: [&str; 4] = ["core", "str", "converts", "from_utf8"];
 pub const STR_LEN: [&str; 4] = ["core", "str", "<impl str>", "len"];
 pub const STR_STARTS_WITH: [&str; 4] = ["core", "str", "<impl str>", "starts_with"];
 pub const SYNTAX_CONTEXT: [&str; 3] = ["rustc_span", "hygiene", "SyntaxContext"];

clippy_lints/src/utils/visitors.rs

@@ -0,0 +1,125 @@
+use rustc_hir as hir;
+use rustc_hir::intravisit::{self, Visitor};
+use rustc_lint::LateContext;
+use rustc_middle::hir::map::Map;
+
+/// returns `true` if expr contains match expr desugared from try
+fn contains_try(expr: &hir::Expr<'_>) -> bool {
+    struct TryFinder {
+        found: bool,
+    }
+
+    impl<'hir> intravisit::Visitor<'hir> for TryFinder {
+        type Map = Map<'hir>;
+
+        fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
+            intravisit::NestedVisitorMap::None
+        }
+
+        fn visit_expr(&mut self, expr: &'hir hir::Expr<'hir>) {
+            if self.found {
+                return;
+            }
+            match expr.kind {
+                hir::ExprKind::Match(_, _, hir::MatchSource::TryDesugar) => self.found = true,
+                _ => intravisit::walk_expr(self, expr),
+            }
+        }
+    }
+
+    let mut visitor = TryFinder { found: false };
+    visitor.visit_expr(expr);
+    visitor.found
+}
+
+pub fn find_all_ret_expressions<'hir, F>(_cx: &LateContext<'_>, expr: &'hir hir::Expr<'hir>, callback: F) -> bool
+where
+    F: FnMut(&'hir hir::Expr<'hir>) -> bool,
+{
+    struct RetFinder<F> {
+        in_stmt: bool,
+        failed: bool,
+        cb: F,
+    }
+
+    struct WithStmtGuarg<'a, F> {
+        val: &'a mut RetFinder<F>,
+        prev_in_stmt: bool,
+    }
+
+    impl<F> RetFinder<F> {
+        fn inside_stmt(&mut self, in_stmt: bool) -> WithStmtGuarg<'_, F> {
+            let prev_in_stmt = std::mem::replace(&mut self.in_stmt, in_stmt);
+            WithStmtGuarg {
+                val: self,
+                prev_in_stmt,
+            }
+        }
+    }
+
+    impl<F> std::ops::Deref for WithStmtGuarg<'_, F> {
+        type Target = RetFinder<F>;
+
+        fn deref(&self) -> &Self::Target {
+            self.val
+        }
+    }
+
+    impl<F> std::ops::DerefMut for WithStmtGuarg<'_, F> {
+        fn deref_mut(&mut self) -> &mut Self::Target {
+            self.val
+        }
+    }
+
+    impl<F> Drop for WithStmtGuarg<'_, F> {
+        fn drop(&mut self) {
+            self.val.in_stmt = self.prev_in_stmt;
+        }
+    }
+
+    impl<'hir, F: FnMut(&'hir hir::Expr<'hir>) -> bool> intravisit::Visitor<'hir> for RetFinder<F> {
+        type Map = Map<'hir>;
+
+        fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
+            intravisit::NestedVisitorMap::None
+        }
+
+        fn visit_stmt(&mut self, stmt: &'hir hir::Stmt<'_>) {
+            intravisit::walk_stmt(&mut *self.inside_stmt(true), stmt)
+        }
+
+        fn visit_expr(&mut self, expr: &'hir hir::Expr<'_>) {
+            if self.failed {
+                return;
+            }
+            if self.in_stmt {
+                match expr.kind {
+                    hir::ExprKind::Ret(Some(expr)) => self.inside_stmt(false).visit_expr(expr),
+                    _ => intravisit::walk_expr(self, expr),
+                }
+            } else {
+                match expr.kind {
+                    hir::ExprKind::Match(cond, arms, _) => {
+                        self.inside_stmt(true).visit_expr(cond);
+                        for arm in arms {
+                            self.visit_expr(arm.body);
+                        }
+                    },
+                    hir::ExprKind::Block(..) => intravisit::walk_expr(self, expr),
+                    hir::ExprKind::Ret(Some(expr)) => self.visit_expr(expr),
+                    _ => self.failed |= !(self.cb)(expr),
+                }
+            }
+        }
+    }
+
+    !contains_try(expr) && {
+        let mut ret_finder = RetFinder {
+            in_stmt: false,
+            failed: false,
+            cb: callback,
+        };
+        ret_finder.visit_expr(expr);
+        !ret_finder.failed
+    }
+}