-#![allow(rustc::default_hash_types)]
-
mod borrowed_box;
mod box_vec;
mod linked_list;
mod option_option;
mod rc_buffer;
mod redundant_allocation;
+mod type_complexity;
mod utils;
mod vec_box;
-use std::borrow::Cow;
-use std::cmp::Ordering;
-use std::collections::BTreeMap;
-
-use if_chain::if_chain;
-use rustc_errors::{Applicability, DiagnosticBuilder};
use rustc_hir as hir;
-use rustc_hir::intravisit::{walk_body, walk_expr, walk_ty, FnKind, NestedVisitorMap, Visitor};
+use rustc_hir::intravisit::FnKind;
use rustc_hir::{
- BinOpKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, FnSig, GenericArg, GenericParamKind, HirId, ImplItem,
- ImplItemKind, Item, ItemKind, Local, MatchSource, MutTy, Node, QPath, Stmt, StmtKind, TraitFn, TraitItem,
+ Body, FnDecl, FnRetTy, GenericArg, HirId, ImplItem, ImplItemKind, Item, ItemKind, Local, MutTy, QPath, TraitItem,
TraitItemKind, TyKind,
};
-use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::hir::map::Map;
-use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, IntTy, Ty, TyS, TypeckResults, UintTy};
-use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass};
-use rustc_span::hygiene::{ExpnKind, MacroKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::source_map::Span;
-use rustc_span::symbol::sym;
-use rustc_target::abi::LayoutOf;
-use rustc_target::spec::abi::Abi;
-use rustc_typeck::hir_ty_to_ty;
-
-use crate::consts::{constant, Constant};
-use crate::utils::paths;
-use crate::utils::{
- clip, comparisons, differing_macro_contexts, higher, indent_of, int_bits, is_isize_or_usize,
- is_type_diagnostic_item, match_path, multispan_sugg, reindent_multiline, sext, snippet, snippet_opt,
- snippet_with_macro_callsite, span_lint, span_lint_and_help, span_lint_and_then, unsext,
-};
declare_clippy_lint! {
/// **What it does:** Checks for use of `Box<Vec<_>>` anywhere in the code.
"shared ownership of a buffer type"
}
+declare_clippy_lint! {
+ /// **What it does:** Checks for types used in structs, parameters and `let`
+ /// declarations above a certain complexity threshold.
+ ///
+ /// **Why is this bad?** Too complex types make the code less readable. Consider
+ /// using a `type` definition to simplify them.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # use std::rc::Rc;
+ /// struct Foo {
+ /// inner: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>>,
+ /// }
+ /// ```
+ pub TYPE_COMPLEXITY,
+ complexity,
+ "usage of very complex types that might be better factored into `type` definitions"
+}
+
pub struct Types {
vec_box_size_threshold: u64,
+ type_complexity_threshold: u64,
}
-impl_lint_pass!(Types => [BOX_VEC, VEC_BOX, OPTION_OPTION, LINKEDLIST, BORROWED_BOX, REDUNDANT_ALLOCATION, RC_BUFFER]);
+impl_lint_pass!(Types => [BOX_VEC, VEC_BOX, OPTION_OPTION, LINKEDLIST, BORROWED_BOX, REDUNDANT_ALLOCATION, RC_BUFFER, TYPE_COMPLEXITY]);
impl<'tcx> LateLintPass<'tcx> for Types {
fn check_fn(&mut self, cx: &LateContext<'_>, _: FnKind<'_>, decl: &FnDecl<'_>, _: &Body<'_>, _: Span, id: HirId) {
- // Skip trait implementations; see issue #605.
- if let Some(hir::Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_item(id)) {
- if let ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }) = item.kind {
- return;
- }
+ let is_in_trait_impl = if let Some(hir::Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_item(id))
+ {
+ matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
+ } else {
+ false
+ };
+
+ self.check_fn_decl(
+ cx,
+ decl,
+ CheckTyContext {
+ is_in_trait_impl,
+ ..CheckTyContext::default()
+ },
+ );
+ }
+
+ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+ match item.kind {
+ ItemKind::Static(ty, _, _) | ItemKind::Const(ty, _) => self.check_ty(cx, ty, CheckTyContext::default()),
+ // functions, enums, structs, impls and traits are covered
+ _ => (),
}
+ }
- self.check_fn_decl(cx, decl);
+ fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
+ match item.kind {
+ ImplItemKind::Const(ty, _) | ImplItemKind::TyAlias(ty) => self.check_ty(
+ cx,
+ ty,
+ CheckTyContext {
+ is_in_trait_impl: true,
+ ..CheckTyContext::default()
+ },
+ ),
+ // methods are covered by check_fn
+ ImplItemKind::Fn(..) => (),
+ }
}
fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) {
- self.check_ty(cx, &field.ty, false);
+ self.check_ty(cx, field.ty, CheckTyContext::default());
}
fn check_trait_item(&mut self, cx: &LateContext<'_>, item: &TraitItem<'_>) {
match item.kind {
- TraitItemKind::Const(ref ty, _) | TraitItemKind::Type(_, Some(ref ty)) => self.check_ty(cx, ty, false),
- TraitItemKind::Fn(ref sig, _) => self.check_fn_decl(cx, &sig.decl),
- _ => (),
+ TraitItemKind::Const(ty, _) | TraitItemKind::Type(_, Some(ty)) => {
+ self.check_ty(cx, ty, CheckTyContext::default())
+ },
+ TraitItemKind::Fn(ref sig, _) => self.check_fn_decl(cx, sig.decl, CheckTyContext::default()),
+ TraitItemKind::Type(..) => (),
}
}
fn check_local(&mut self, cx: &LateContext<'_>, local: &Local<'_>) {
- if let Some(ref ty) = local.ty {
- self.check_ty(cx, ty, true);
+ if let Some(ty) = local.ty {
+ self.check_ty(
+ cx,
+ ty,
+ CheckTyContext {
+ is_local: true,
+ ..CheckTyContext::default()
+ },
+ );
}
}
}
impl Types {
- pub fn new(vec_box_size_threshold: u64) -> Self {
- Self { vec_box_size_threshold }
+ pub fn new(vec_box_size_threshold: u64, type_complexity_threshold: u64) -> Self {
+ Self {
+ vec_box_size_threshold,
+ type_complexity_threshold,
+ }
}
- fn check_fn_decl(&mut self, cx: &LateContext<'_>, decl: &FnDecl<'_>) {
+ fn check_fn_decl(&mut self, cx: &LateContext<'_>, decl: &FnDecl<'_>, context: CheckTyContext) {
for input in decl.inputs {
- self.check_ty(cx, input, false);
+ self.check_ty(cx, input, context);
}
- if let FnRetTy::Return(ref ty) = decl.output {
- self.check_ty(cx, ty, false);
+ if let FnRetTy::Return(ty) = decl.output {
+ self.check_ty(cx, ty, context);
}
}
/// lint found.
///
/// The parameter `is_local` distinguishes the context of the type.
- fn check_ty(&mut self, cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>, is_local: bool) {
+ fn check_ty(&mut self, cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>, mut context: CheckTyContext) {
if hir_ty.span.from_expansion() {
return;
}
+
+ if !context.is_nested_call && type_complexity::check(cx, hir_ty, self.type_complexity_threshold) {
+ return;
+ }
+
+ // Skip trait implementations; see issue #605.
+ if context.is_in_trait_impl {
+ return;
+ }
+
match hir_ty.kind {
- TyKind::Path(ref qpath) if !is_local => {
+ TyKind::Path(ref qpath) if !context.is_local => {
let hir_id = hir_ty.hir_id;
let res = cx.qpath_res(qpath, hir_id);
if let Some(def_id) = res.opt_def_id() {
}
}
match *qpath {
- QPath::Resolved(Some(ref ty), ref p) => {
- self.check_ty(cx, ty, is_local);
+ QPath::Resolved(Some(ty), p) => {
+ context.is_nested_call = true;
+ self.check_ty(cx, ty, context);
for ty in p.segments.iter().flat_map(|seg| {
seg.args
.as_ref()
_ => None,
})
}) {
- self.check_ty(cx, ty, is_local);
+ self.check_ty(cx, ty, context);
}
},
- QPath::Resolved(None, ref p) => {
+ QPath::Resolved(None, p) => {
+ context.is_nested_call = true;
for ty in p.segments.iter().flat_map(|seg| {
seg.args
.as_ref()
_ => None,
})
}) {
- self.check_ty(cx, ty, is_local);
+ self.check_ty(cx, ty, context);
}
},
- QPath::TypeRelative(ref ty, ref seg) => {
- self.check_ty(cx, ty, is_local);
- if let Some(ref params) = seg.args {
+ QPath::TypeRelative(ty, seg) => {
+ context.is_nested_call = true;
+ self.check_ty(cx, ty, context);
+ if let Some(params) = seg.args {
for ty in params.args.iter().filter_map(|arg| match arg {
GenericArg::Type(ty) => Some(ty),
_ => None,
}) {
- self.check_ty(cx, ty, is_local);
+ self.check_ty(cx, ty, context);
}
}
},
}
},
TyKind::Rptr(ref lt, ref mut_ty) => {
+ context.is_nested_call = true;
if !borrowed_box::check(cx, hir_ty, lt, mut_ty) {
- self.check_ty(cx, &mut_ty.ty, is_local);
+ self.check_ty(cx, mut_ty.ty, context);
}
},
- TyKind::Slice(ref ty) | TyKind::Array(ref ty, _) | TyKind::Ptr(MutTy { ref ty, .. }) => {
- self.check_ty(cx, ty, is_local)
+ TyKind::Slice(ty) | TyKind::Array(ty, _) | TyKind::Ptr(MutTy { ty, .. }) => {
+ context.is_nested_call = true;
+ self.check_ty(cx, ty, context)
},
TyKind::Tup(tys) => {
+ context.is_nested_call = true;
for ty in tys {
- self.check_ty(cx, ty, is_local);
- }
- },
- _ => {},
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for binding a unit value.
- ///
- /// **Why is this bad?** A unit value cannot usefully be used anywhere. So
- /// binding one is kind of pointless.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
- /// ```rust
- /// let x = {
- /// 1;
- /// };
- /// ```
- pub LET_UNIT_VALUE,
- pedantic,
- "creating a `let` binding to a value of unit type, which usually can't be used afterwards"
-}
-
-declare_lint_pass!(LetUnitValue => [LET_UNIT_VALUE]);
-
-impl<'tcx> LateLintPass<'tcx> for LetUnitValue {
- fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
- if let StmtKind::Local(ref local) = stmt.kind {
- if is_unit(cx.typeck_results().pat_ty(&local.pat)) {
- if in_external_macro(cx.sess(), stmt.span) || local.pat.span.from_expansion() {
- return;
- }
- if higher::is_from_for_desugar(local) {
- return;
- }
- span_lint_and_then(
- cx,
- LET_UNIT_VALUE,
- stmt.span,
- "this let-binding has unit value",
- |diag| {
- if let Some(expr) = &local.init {
- let snip = snippet_with_macro_callsite(cx, expr.span, "()");
- diag.span_suggestion(
- stmt.span,
- "omit the `let` binding",
- format!("{};", snip),
- Applicability::MachineApplicable, // snippet
- );
- }
- },
- );
- }
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for comparisons to unit. This includes all binary
- /// comparisons (like `==` and `<`) and asserts.
- ///
- /// **Why is this bad?** Unit is always equal to itself, and thus is just a
- /// clumsily written constant. Mostly this happens when someone accidentally
- /// adds semicolons at the end of the operands.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
- /// ```rust
- /// # fn foo() {};
- /// # fn bar() {};
- /// # fn baz() {};
- /// if {
- /// foo();
- /// } == {
- /// bar();
- /// } {
- /// baz();
- /// }
- /// ```
- /// is equal to
- /// ```rust
- /// # fn foo() {};
- /// # fn bar() {};
- /// # fn baz() {};
- /// {
- /// foo();
- /// bar();
- /// baz();
- /// }
- /// ```
- ///
- /// For asserts:
- /// ```rust
- /// # fn foo() {};
- /// # fn bar() {};
- /// assert_eq!({ foo(); }, { bar(); });
- /// ```
- /// will always succeed
- pub UNIT_CMP,
- correctness,
- "comparing unit values"
-}
-
-declare_lint_pass!(UnitCmp => [UNIT_CMP]);
-
-impl<'tcx> LateLintPass<'tcx> for UnitCmp {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
- if expr.span.from_expansion() {
- if let Some(callee) = expr.span.source_callee() {
- if let ExpnKind::Macro(MacroKind::Bang, symbol) = callee.kind {
- if let ExprKind::Binary(ref cmp, ref left, _) = expr.kind {
- let op = cmp.node;
- if op.is_comparison() && is_unit(cx.typeck_results().expr_ty(left)) {
- let result = match &*symbol.as_str() {
- "assert_eq" | "debug_assert_eq" => "succeed",
- "assert_ne" | "debug_assert_ne" => "fail",
- _ => return,
- };
- span_lint(
- cx,
- UNIT_CMP,
- expr.span,
- &format!(
- "`{}` of unit values detected. This will always {}",
- symbol.as_str(),
- result
- ),
- );
- }
- }
- }
- }
- return;
- }
- if let ExprKind::Binary(ref cmp, ref left, _) = expr.kind {
- let op = cmp.node;
- if op.is_comparison() && is_unit(cx.typeck_results().expr_ty(left)) {
- let result = match op {
- BinOpKind::Eq | BinOpKind::Le | BinOpKind::Ge => "true",
- _ => "false",
- };
- span_lint(
- cx,
- UNIT_CMP,
- expr.span,
- &format!(
- "{}-comparison of unit values detected. This will always be {}",
- op.as_str(),
- result
- ),
- );
- }
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for passing a unit value as an argument to a function without using a
- /// unit literal (`()`).
- ///
- /// **Why is this bad?** This is likely the result of an accidental semicolon.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
- /// ```rust,ignore
- /// foo({
- /// let a = bar();
- /// baz(a);
- /// })
- /// ```
- pub UNIT_ARG,
- complexity,
- "passing unit to a function"
-}
-
-declare_lint_pass!(UnitArg => [UNIT_ARG]);
-
-impl<'tcx> LateLintPass<'tcx> for UnitArg {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if expr.span.from_expansion() {
- return;
- }
-
- // apparently stuff in the desugaring of `?` can trigger this
- // so check for that here
- // only the calls to `Try::from_error` is marked as desugared,
- // so we need to check both the current Expr and its parent.
- if is_questionmark_desugar_marked_call(expr) {
- return;
- }
- if_chain! {
- let map = &cx.tcx.hir();
- let opt_parent_node = map.find(map.get_parent_node(expr.hir_id));
- if let Some(hir::Node::Expr(parent_expr)) = opt_parent_node;
- if is_questionmark_desugar_marked_call(parent_expr);
- then {
- return;
- }
- }
-
- match expr.kind {
- ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) => {
- let args_to_recover = args
- .iter()
- .filter(|arg| {
- if is_unit(cx.typeck_results().expr_ty(arg)) && !is_unit_literal(arg) {
- !matches!(
- &arg.kind,
- ExprKind::Match(.., MatchSource::TryDesugar) | ExprKind::Path(..)
- )
- } else {
- false
- }
- })
- .collect::<Vec<_>>();
- if !args_to_recover.is_empty() {
- lint_unit_args(cx, expr, &args_to_recover);
- }
- },
- _ => (),
- }
- }
-}
-
-fn fmt_stmts_and_call(
- cx: &LateContext<'_>,
- call_expr: &Expr<'_>,
- call_snippet: &str,
- args_snippets: &[impl AsRef<str>],
- non_empty_block_args_snippets: &[impl AsRef<str>],
-) -> String {
- let call_expr_indent = indent_of(cx, call_expr.span).unwrap_or(0);
- let call_snippet_with_replacements = args_snippets
- .iter()
- .fold(call_snippet.to_owned(), |acc, arg| acc.replacen(arg.as_ref(), "()", 1));
-
- let mut stmts_and_call = non_empty_block_args_snippets
- .iter()
- .map(|it| it.as_ref().to_owned())
- .collect::<Vec<_>>();
- stmts_and_call.push(call_snippet_with_replacements);
- stmts_and_call = stmts_and_call
- .into_iter()
- .map(|v| reindent_multiline(v.into(), true, Some(call_expr_indent)).into_owned())
- .collect();
-
- let mut stmts_and_call_snippet = stmts_and_call.join(&format!("{}{}", ";\n", " ".repeat(call_expr_indent)));
- // expr is not in a block statement or result expression position, wrap in a block
- let parent_node = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(call_expr.hir_id));
- if !matches!(parent_node, Some(Node::Block(_))) && !matches!(parent_node, Some(Node::Stmt(_))) {
- let block_indent = call_expr_indent + 4;
- stmts_and_call_snippet =
- reindent_multiline(stmts_and_call_snippet.into(), true, Some(block_indent)).into_owned();
- stmts_and_call_snippet = format!(
- "{{\n{}{}\n{}}}",
- " ".repeat(block_indent),
- &stmts_and_call_snippet,
- " ".repeat(call_expr_indent)
- );
- }
- stmts_and_call_snippet
-}
-
-fn lint_unit_args(cx: &LateContext<'_>, expr: &Expr<'_>, args_to_recover: &[&Expr<'_>]) {
- let mut applicability = Applicability::MachineApplicable;
- let (singular, plural) = if args_to_recover.len() > 1 {
- ("", "s")
- } else {
- ("a ", "")
- };
- span_lint_and_then(
- cx,
- UNIT_ARG,
- expr.span,
- &format!("passing {}unit value{} to a function", singular, plural),
- |db| {
- let mut or = "";
- args_to_recover
- .iter()
- .filter_map(|arg| {
- if_chain! {
- if let ExprKind::Block(block, _) = arg.kind;
- if block.expr.is_none();
- if let Some(last_stmt) = block.stmts.iter().last();
- if let StmtKind::Semi(last_expr) = last_stmt.kind;
- if let Some(snip) = snippet_opt(cx, last_expr.span);
- then {
- Some((
- last_stmt.span,
- snip,
- ))
- }
- else {
- None
- }
- }
- })
- .for_each(|(span, sugg)| {
- db.span_suggestion(
- span,
- "remove the semicolon from the last statement in the block",
- sugg,
- Applicability::MaybeIncorrect,
- );
- or = "or ";
- applicability = Applicability::MaybeIncorrect;
- });
-
- let arg_snippets: Vec<String> = args_to_recover
- .iter()
- .filter_map(|arg| snippet_opt(cx, arg.span))
- .collect();
- let arg_snippets_without_empty_blocks: Vec<String> = args_to_recover
- .iter()
- .filter(|arg| !is_empty_block(arg))
- .filter_map(|arg| snippet_opt(cx, arg.span))
- .collect();
-
- if let Some(call_snippet) = snippet_opt(cx, expr.span) {
- let sugg = fmt_stmts_and_call(
- cx,
- expr,
- &call_snippet,
- &arg_snippets,
- &arg_snippets_without_empty_blocks,
- );
-
- if arg_snippets_without_empty_blocks.is_empty() {
- db.multipart_suggestion(
- &format!("use {}unit literal{} instead", singular, plural),
- args_to_recover
- .iter()
- .map(|arg| (arg.span, "()".to_string()))
- .collect::<Vec<_>>(),
- applicability,
- );
- } else {
- let plural = arg_snippets_without_empty_blocks.len() > 1;
- let empty_or_s = if plural { "s" } else { "" };
- let it_or_them = if plural { "them" } else { "it" };
- db.span_suggestion(
- expr.span,
- &format!(
- "{}move the expression{} in front of the call and replace {} with the unit literal `()`",
- or, empty_or_s, it_or_them
- ),
- sugg,
- applicability,
- );
- }
- }
- },
- );
-}
-
-fn is_empty_block(expr: &Expr<'_>) -> bool {
- matches!(
- expr.kind,
- ExprKind::Block(
- Block {
- stmts: &[],
- expr: None,
- ..
- },
- _,
- )
- )
-}
-
-fn is_questionmark_desugar_marked_call(expr: &Expr<'_>) -> bool {
- use rustc_span::hygiene::DesugaringKind;
- if let ExprKind::Call(ref callee, _) = expr.kind {
- callee.span.is_desugaring(DesugaringKind::QuestionMark)
- } else {
- false
- }
-}
-
-fn is_unit(ty: Ty<'_>) -> bool {
- matches!(ty.kind(), ty::Tuple(slice) if slice.is_empty())
-}
-
-fn is_unit_literal(expr: &Expr<'_>) -> bool {
- matches!(expr.kind, ExprKind::Tup(ref slice) if slice.is_empty())
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for types used in structs, parameters and `let`
- /// declarations above a certain complexity threshold.
- ///
- /// **Why is this bad?** Too complex types make the code less readable. Consider
- /// using a `type` definition to simplify them.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
- /// ```rust
- /// # use std::rc::Rc;
- /// struct Foo {
- /// inner: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>>,
- /// }
- /// ```
- pub TYPE_COMPLEXITY,
- complexity,
- "usage of very complex types that might be better factored into `type` definitions"
-}
-
-pub struct TypeComplexity {
- threshold: u64,
-}
-
-impl TypeComplexity {
- #[must_use]
- pub fn new(threshold: u64) -> Self {
- Self { threshold }
- }
-}
-
-impl_lint_pass!(TypeComplexity => [TYPE_COMPLEXITY]);
-
-impl<'tcx> LateLintPass<'tcx> for TypeComplexity {
- fn check_fn(
- &mut self,
- cx: &LateContext<'tcx>,
- _: FnKind<'tcx>,
- decl: &'tcx FnDecl<'_>,
- _: &'tcx Body<'_>,
- _: Span,
- _: HirId,
- ) {
- self.check_fndecl(cx, decl);
- }
-
- fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &'tcx hir::FieldDef<'_>) {
- // enum variants are also struct fields now
- self.check_type(cx, &field.ty);
- }
-
- fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
- match item.kind {
- ItemKind::Static(ref ty, _, _) | ItemKind::Const(ref ty, _) => self.check_type(cx, ty),
- // functions, enums, structs, impls and traits are covered
- _ => (),
- }
- }
-
- fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_>) {
- match item.kind {
- TraitItemKind::Const(ref ty, _) | TraitItemKind::Type(_, Some(ref ty)) => self.check_type(cx, ty),
- TraitItemKind::Fn(FnSig { ref decl, .. }, TraitFn::Required(_)) => self.check_fndecl(cx, decl),
- // methods with default impl are covered by check_fn
- _ => (),
- }
- }
-
- fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
- match item.kind {
- ImplItemKind::Const(ref ty, _) | ImplItemKind::TyAlias(ref ty) => self.check_type(cx, ty),
- // methods are covered by check_fn
- _ => (),
- }
- }
-
- fn check_local(&mut self, cx: &LateContext<'tcx>, local: &'tcx Local<'_>) {
- if let Some(ref ty) = local.ty {
- self.check_type(cx, ty);
- }
- }
-}
-
-impl<'tcx> TypeComplexity {
- fn check_fndecl(&self, cx: &LateContext<'tcx>, decl: &'tcx FnDecl<'_>) {
- for arg in decl.inputs {
- self.check_type(cx, arg);
- }
- if let FnRetTy::Return(ref ty) = decl.output {
- self.check_type(cx, ty);
- }
- }
-
- fn check_type(&self, cx: &LateContext<'_>, ty: &hir::Ty<'_>) {
- if ty.span.from_expansion() {
- return;
- }
- let score = {
- let mut visitor = TypeComplexityVisitor { score: 0, nest: 1 };
- visitor.visit_ty(ty);
- visitor.score
- };
-
- if score > self.threshold {
- span_lint(
- cx,
- TYPE_COMPLEXITY,
- ty.span,
- "very complex type used. Consider factoring parts into `type` definitions",
- );
- }
- }
-}
-
-/// Walks a type and assigns a complexity score to it.
-struct TypeComplexityVisitor {
- /// total complexity score of the type
- score: u64,
- /// current nesting level
- nest: u64,
-}
-
-impl<'tcx> Visitor<'tcx> for TypeComplexityVisitor {
- type Map = Map<'tcx>;
-
- fn visit_ty(&mut self, ty: &'tcx hir::Ty<'_>) {
- let (add_score, sub_nest) = match ty.kind {
- // _, &x and *x have only small overhead; don't mess with nesting level
- TyKind::Infer | TyKind::Ptr(..) | TyKind::Rptr(..) => (1, 0),
-
- // the "normal" components of a type: named types, arrays/tuples
- TyKind::Path(..) | TyKind::Slice(..) | TyKind::Tup(..) | TyKind::Array(..) => (10 * self.nest, 1),
-
- // function types bring a lot of overhead
- TyKind::BareFn(ref bare) if bare.abi == Abi::Rust => (50 * self.nest, 1),
-
- TyKind::TraitObject(ref param_bounds, ..) => {
- let has_lifetime_parameters = param_bounds.iter().any(|bound| {
- bound
- .bound_generic_params
- .iter()
- .any(|gen| matches!(gen.kind, GenericParamKind::Lifetime { .. }))
- });
- if has_lifetime_parameters {
- // complex trait bounds like A<'a, 'b>
- (50 * self.nest, 1)
- } else {
- // simple trait bounds like A + B
- (20 * self.nest, 0)
- }
- },
-
- _ => (0, 0),
- };
- self.score += add_score;
- self.nest += sub_nest;
- walk_ty(self, ty);
- self.nest -= sub_nest;
- }
- fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
- NestedVisitorMap::None
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for comparisons where one side of the relation is
- /// either the minimum or maximum value for its type and warns if it involves a
- /// case that is always true or always false. Only integer and boolean types are
- /// checked.
- ///
- /// **Why is this bad?** An expression like `min <= x` may misleadingly imply
- /// that it is possible for `x` to be less than the minimum. Expressions like
- /// `max < x` are probably mistakes.
- ///
- /// **Known problems:** For `usize` the size of the current compile target will
- /// be assumed (e.g., 64 bits on 64 bit systems). This means code that uses such
- /// a comparison to detect target pointer width will trigger this lint. One can
- /// use `mem::sizeof` and compare its value or conditional compilation
- /// attributes
- /// like `#[cfg(target_pointer_width = "64")] ..` instead.
- ///
- /// **Example:**
- ///
- /// ```rust
- /// let vec: Vec<isize> = Vec::new();
- /// if vec.len() <= 0 {}
- /// if 100 > i32::MAX {}
- /// ```
- pub ABSURD_EXTREME_COMPARISONS,
- correctness,
- "a comparison with a maximum or minimum value that is always true or false"
-}
-
-declare_lint_pass!(AbsurdExtremeComparisons => [ABSURD_EXTREME_COMPARISONS]);
-
-enum ExtremeType {
- Minimum,
- Maximum,
-}
-
-struct ExtremeExpr<'a> {
- which: ExtremeType,
- expr: &'a Expr<'a>,
-}
-
-enum AbsurdComparisonResult {
- AlwaysFalse,
- AlwaysTrue,
- InequalityImpossible,
-}
-
-fn is_cast_between_fixed_and_target<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
- if let ExprKind::Cast(ref cast_exp, _) = expr.kind {
- let precast_ty = cx.typeck_results().expr_ty(cast_exp);
- let cast_ty = cx.typeck_results().expr_ty(expr);
-
- return is_isize_or_usize(precast_ty) != is_isize_or_usize(cast_ty);
- }
-
- false
-}
-
-fn detect_absurd_comparison<'tcx>(
- cx: &LateContext<'tcx>,
- op: BinOpKind,
- lhs: &'tcx Expr<'_>,
- rhs: &'tcx Expr<'_>,
-) -> Option<(ExtremeExpr<'tcx>, AbsurdComparisonResult)> {
- use crate::types::AbsurdComparisonResult::{AlwaysFalse, AlwaysTrue, InequalityImpossible};
- use crate::types::ExtremeType::{Maximum, Minimum};
- use crate::utils::comparisons::{normalize_comparison, Rel};
-
- // absurd comparison only makes sense on primitive types
- // primitive types don't implement comparison operators with each other
- if cx.typeck_results().expr_ty(lhs) != cx.typeck_results().expr_ty(rhs) {
- return None;
- }
-
- // comparisons between fix sized types and target sized types are considered unanalyzable
- if is_cast_between_fixed_and_target(cx, lhs) || is_cast_between_fixed_and_target(cx, rhs) {
- return None;
- }
-
- let (rel, normalized_lhs, normalized_rhs) = normalize_comparison(op, lhs, rhs)?;
-
- let lx = detect_extreme_expr(cx, normalized_lhs);
- let rx = detect_extreme_expr(cx, normalized_rhs);
-
- Some(match rel {
- Rel::Lt => {
- match (lx, rx) {
- (Some(l @ ExtremeExpr { which: Maximum, .. }), _) => (l, AlwaysFalse), // max < x
- (_, Some(r @ ExtremeExpr { which: Minimum, .. })) => (r, AlwaysFalse), // x < min
- _ => return None,
- }
- },
- Rel::Le => {
- match (lx, rx) {
- (Some(l @ ExtremeExpr { which: Minimum, .. }), _) => (l, AlwaysTrue), // min <= x
- (Some(l @ ExtremeExpr { which: Maximum, .. }), _) => (l, InequalityImpossible), // max <= x
- (_, Some(r @ ExtremeExpr { which: Minimum, .. })) => (r, InequalityImpossible), // x <= min
- (_, Some(r @ ExtremeExpr { which: Maximum, .. })) => (r, AlwaysTrue), // x <= max
- _ => return None,
- }
- },
- Rel::Ne | Rel::Eq => return None,
- })
-}
-
-fn detect_extreme_expr<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<ExtremeExpr<'tcx>> {
- use crate::types::ExtremeType::{Maximum, Minimum};
-
- let ty = cx.typeck_results().expr_ty(expr);
-
- let cv = constant(cx, cx.typeck_results(), expr)?.0;
-
- let which = match (ty.kind(), cv) {
- (&ty::Bool, Constant::Bool(false)) | (&ty::Uint(_), Constant::Int(0)) => Minimum,
- (&ty::Int(ity), Constant::Int(i)) if i == unsext(cx.tcx, i128::MIN >> (128 - int_bits(cx.tcx, ity)), ity) => {
- Minimum
- },
-
- (&ty::Bool, Constant::Bool(true)) => Maximum,
- (&ty::Int(ity), Constant::Int(i)) if i == unsext(cx.tcx, i128::MAX >> (128 - int_bits(cx.tcx, ity)), ity) => {
- Maximum
- },
- (&ty::Uint(uty), Constant::Int(i)) if clip(cx.tcx, u128::MAX, uty) == i => Maximum,
-
- _ => return None,
- };
- Some(ExtremeExpr { which, expr })
-}
-
-impl<'tcx> LateLintPass<'tcx> for AbsurdExtremeComparisons {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- use crate::types::AbsurdComparisonResult::{AlwaysFalse, AlwaysTrue, InequalityImpossible};
- use crate::types::ExtremeType::{Maximum, Minimum};
-
- if let ExprKind::Binary(ref cmp, ref lhs, ref rhs) = expr.kind {
- if let Some((culprit, result)) = detect_absurd_comparison(cx, cmp.node, lhs, rhs) {
- if !expr.span.from_expansion() {
- let msg = "this comparison involving the minimum or maximum element for this \
- type contains a case that is always true or always false";
-
- let conclusion = match result {
- AlwaysFalse => "this comparison is always false".to_owned(),
- AlwaysTrue => "this comparison is always true".to_owned(),
- InequalityImpossible => format!(
- "the case where the two sides are not equal never occurs, consider using `{} == {}` \
- instead",
- snippet(cx, lhs.span, "lhs"),
- snippet(cx, rhs.span, "rhs")
- ),
- };
-
- let help = format!(
- "because `{}` is the {} value for this type, {}",
- snippet(cx, culprit.expr.span, "x"),
- match culprit.which {
- Minimum => "minimum",
- Maximum => "maximum",
- },
- conclusion
- );
-
- span_lint_and_help(cx, ABSURD_EXTREME_COMPARISONS, expr.span, msg, None, &help);
- }
- }
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for comparisons where the relation is always either
- /// true or false, but where one side has been upcast so that the comparison is
- /// necessary. Only integer types are checked.
- ///
- /// **Why is this bad?** An expression like `let x : u8 = ...; (x as u32) > 300`
- /// will mistakenly imply that it is possible for `x` to be outside the range of
- /// `u8`.
- ///
- /// **Known problems:**
- /// https://github.com/rust-lang/rust-clippy/issues/886
- ///
- /// **Example:**
- /// ```rust
- /// let x: u8 = 1;
- /// (x as u32) > 300;
- /// ```
- pub INVALID_UPCAST_COMPARISONS,
- pedantic,
- "a comparison involving an upcast which is always true or false"
-}
-
-declare_lint_pass!(InvalidUpcastComparisons => [INVALID_UPCAST_COMPARISONS]);
-
-#[derive(Copy, Clone, Debug, Eq)]
-enum FullInt {
- S(i128),
- U(u128),
-}
-
-impl FullInt {
- #[allow(clippy::cast_sign_loss)]
- #[must_use]
- fn cmp_s_u(s: i128, u: u128) -> Ordering {
- if s < 0 {
- Ordering::Less
- } else if u > (i128::MAX as u128) {
- Ordering::Greater
- } else {
- (s as u128).cmp(&u)
- }
- }
-}
-
-impl PartialEq for FullInt {
- #[must_use]
- fn eq(&self, other: &Self) -> bool {
- self.partial_cmp(other).expect("`partial_cmp` only returns `Some(_)`") == Ordering::Equal
- }
-}
-
-impl PartialOrd for FullInt {
- #[must_use]
- fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
- Some(match (self, other) {
- (&Self::S(s), &Self::S(o)) => s.cmp(&o),
- (&Self::U(s), &Self::U(o)) => s.cmp(&o),
- (&Self::S(s), &Self::U(o)) => Self::cmp_s_u(s, o),
- (&Self::U(s), &Self::S(o)) => Self::cmp_s_u(o, s).reverse(),
- })
- }
-}
-
-impl Ord for FullInt {
- #[must_use]
- fn cmp(&self, other: &Self) -> Ordering {
- self.partial_cmp(other)
- .expect("`partial_cmp` for FullInt can never return `None`")
- }
-}
-
-fn numeric_cast_precast_bounds<'a>(cx: &LateContext<'_>, expr: &'a Expr<'_>) -> Option<(FullInt, FullInt)> {
- if let ExprKind::Cast(ref cast_exp, _) = expr.kind {
- let pre_cast_ty = cx.typeck_results().expr_ty(cast_exp);
- let cast_ty = cx.typeck_results().expr_ty(expr);
- // if it's a cast from i32 to u32 wrapping will invalidate all these checks
- if cx.layout_of(pre_cast_ty).ok().map(|l| l.size) == cx.layout_of(cast_ty).ok().map(|l| l.size) {
- return None;
- }
- match pre_cast_ty.kind() {
- ty::Int(int_ty) => Some(match int_ty {
- IntTy::I8 => (FullInt::S(i128::from(i8::MIN)), FullInt::S(i128::from(i8::MAX))),
- IntTy::I16 => (FullInt::S(i128::from(i16::MIN)), FullInt::S(i128::from(i16::MAX))),
- IntTy::I32 => (FullInt::S(i128::from(i32::MIN)), FullInt::S(i128::from(i32::MAX))),
- IntTy::I64 => (FullInt::S(i128::from(i64::MIN)), FullInt::S(i128::from(i64::MAX))),
- IntTy::I128 => (FullInt::S(i128::MIN), FullInt::S(i128::MAX)),
- IntTy::Isize => (FullInt::S(isize::MIN as i128), FullInt::S(isize::MAX as i128)),
- }),
- ty::Uint(uint_ty) => Some(match uint_ty {
- UintTy::U8 => (FullInt::U(u128::from(u8::MIN)), FullInt::U(u128::from(u8::MAX))),
- UintTy::U16 => (FullInt::U(u128::from(u16::MIN)), FullInt::U(u128::from(u16::MAX))),
- UintTy::U32 => (FullInt::U(u128::from(u32::MIN)), FullInt::U(u128::from(u32::MAX))),
- UintTy::U64 => (FullInt::U(u128::from(u64::MIN)), FullInt::U(u128::from(u64::MAX))),
- UintTy::U128 => (FullInt::U(u128::MIN), FullInt::U(u128::MAX)),
- UintTy::Usize => (FullInt::U(usize::MIN as u128), FullInt::U(usize::MAX as u128)),
- }),
- _ => None,
- }
- } else {
- None
- }
-}
-
-fn node_as_const_fullint<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<FullInt> {
- let val = constant(cx, cx.typeck_results(), expr)?.0;
- if let Constant::Int(const_int) = val {
- match *cx.typeck_results().expr_ty(expr).kind() {
- ty::Int(ity) => Some(FullInt::S(sext(cx.tcx, const_int, ity))),
- ty::Uint(_) => Some(FullInt::U(const_int)),
- _ => None,
- }
- } else {
- None
- }
-}
-
-fn err_upcast_comparison(cx: &LateContext<'_>, span: Span, expr: &Expr<'_>, always: bool) {
- if let ExprKind::Cast(ref cast_val, _) = expr.kind {
- span_lint(
- cx,
- INVALID_UPCAST_COMPARISONS,
- span,
- &format!(
- "because of the numeric bounds on `{}` prior to casting, this expression is always {}",
- snippet(cx, cast_val.span, "the expression"),
- if always { "true" } else { "false" },
- ),
- );
- }
-}
-
-fn upcast_comparison_bounds_err<'tcx>(
- cx: &LateContext<'tcx>,
- span: Span,
- rel: comparisons::Rel,
- lhs_bounds: Option<(FullInt, FullInt)>,
- lhs: &'tcx Expr<'_>,
- rhs: &'tcx Expr<'_>,
- invert: bool,
-) {
- use crate::utils::comparisons::Rel;
-
- if let Some((lb, ub)) = lhs_bounds {
- if let Some(norm_rhs_val) = node_as_const_fullint(cx, rhs) {
- if rel == Rel::Eq || rel == Rel::Ne {
- if norm_rhs_val < lb || norm_rhs_val > ub {
- err_upcast_comparison(cx, span, lhs, rel == Rel::Ne);
- }
- } else if match rel {
- Rel::Lt => {
- if invert {
- norm_rhs_val < lb
- } else {
- ub < norm_rhs_val
- }
- },
- Rel::Le => {
- if invert {
- norm_rhs_val <= lb
- } else {
- ub <= norm_rhs_val
- }
- },
- Rel::Eq | Rel::Ne => unreachable!(),
- } {
- err_upcast_comparison(cx, span, lhs, true)
- } else if match rel {
- Rel::Lt => {
- if invert {
- norm_rhs_val >= ub
- } else {
- lb >= norm_rhs_val
- }
- },
- Rel::Le => {
- if invert {
- norm_rhs_val > ub
- } else {
- lb > norm_rhs_val
- }
- },
- Rel::Eq | Rel::Ne => unreachable!(),
- } {
- err_upcast_comparison(cx, span, lhs, false)
- }
- }
- }
-}
-
-impl<'tcx> LateLintPass<'tcx> for InvalidUpcastComparisons {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if let ExprKind::Binary(ref cmp, ref lhs, ref rhs) = expr.kind {
- let normalized = comparisons::normalize_comparison(cmp.node, lhs, rhs);
- let (rel, normalized_lhs, normalized_rhs) = if let Some(val) = normalized {
- val
- } else {
- return;
- };
-
- let lhs_bounds = numeric_cast_precast_bounds(cx, normalized_lhs);
- let rhs_bounds = numeric_cast_precast_bounds(cx, normalized_rhs);
-
- upcast_comparison_bounds_err(cx, expr.span, rel, lhs_bounds, normalized_lhs, normalized_rhs, false);
- upcast_comparison_bounds_err(cx, expr.span, rel, rhs_bounds, normalized_rhs, normalized_lhs, true);
- }
- }
-}
-
-declare_clippy_lint! {
- /// **What it does:** Checks for public `impl` or `fn` missing generalization
- /// over different hashers and implicitly defaulting to the default hashing
- /// algorithm (`SipHash`).
- ///
- /// **Why is this bad?** `HashMap` or `HashSet` with custom hashers cannot be
- /// used with them.
- ///
- /// **Known problems:** Suggestions for replacing constructors can contain
- /// false-positives. Also applying suggestions can require modification of other
- /// pieces of code, possibly including external crates.
- ///
- /// **Example:**
- /// ```rust
- /// # use std::collections::HashMap;
- /// # use std::hash::{Hash, BuildHasher};
- /// # trait Serialize {};
- /// impl<K: Hash + Eq, V> Serialize for HashMap<K, V> { }
- ///
- /// pub fn foo(map: &mut HashMap<i32, i32>) { }
- /// ```
- /// could be rewritten as
- /// ```rust
- /// # use std::collections::HashMap;
- /// # use std::hash::{Hash, BuildHasher};
- /// # trait Serialize {};
- /// impl<K: Hash + Eq, V, S: BuildHasher> Serialize for HashMap<K, V, S> { }
- ///
- /// pub fn foo<S: BuildHasher>(map: &mut HashMap<i32, i32, S>) { }
- /// ```
- pub IMPLICIT_HASHER,
- pedantic,
- "missing generalization over different hashers"
-}
-
-declare_lint_pass!(ImplicitHasher => [IMPLICIT_HASHER]);
-
-impl<'tcx> LateLintPass<'tcx> for ImplicitHasher {
- #[allow(clippy::cast_possible_truncation, clippy::too_many_lines)]
- fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
- use rustc_span::BytePos;
-
- fn suggestion<'tcx>(
- cx: &LateContext<'tcx>,
- diag: &mut DiagnosticBuilder<'_>,
- generics_span: Span,
- generics_suggestion_span: Span,
- target: &ImplicitHasherType<'_>,
- vis: ImplicitHasherConstructorVisitor<'_, '_, '_>,
- ) {
- let generics_snip = snippet(cx, generics_span, "");
- // trim `<` `>`
- let generics_snip = if generics_snip.is_empty() {
- ""
- } else {
- &generics_snip[1..generics_snip.len() - 1]
- };
-
- multispan_sugg(
- diag,
- "consider adding a type parameter",
- vec![
- (
- generics_suggestion_span,
- format!(
- "<{}{}S: ::std::hash::BuildHasher{}>",
- generics_snip,
- if generics_snip.is_empty() { "" } else { ", " },
- if vis.suggestions.is_empty() {
- ""
- } else {
- // request users to add `Default` bound so that generic constructors can be used
- " + Default"
- },
- ),
- ),
- (
- target.span(),
- format!("{}<{}, S>", target.type_name(), target.type_arguments(),),
- ),
- ],
- );
-
- if !vis.suggestions.is_empty() {
- multispan_sugg(diag, "...and use generic constructor", vis.suggestions);
- }
- }
-
- if !cx.access_levels.is_exported(item.hir_id()) {
- return;
- }
-
- match item.kind {
- ItemKind::Impl(ref impl_) => {
- let mut vis = ImplicitHasherTypeVisitor::new(cx);
- vis.visit_ty(impl_.self_ty);
-
- for target in &vis.found {
- if differing_macro_contexts(item.span, target.span()) {
- return;
- }
-
- let generics_suggestion_span = impl_.generics.span.substitute_dummy({
- let pos = snippet_opt(cx, item.span.until(target.span()))
- .and_then(|snip| Some(item.span.lo() + BytePos(snip.find("impl")? as u32 + 4)));
- if let Some(pos) = pos {
- Span::new(pos, pos, item.span.data().ctxt)
- } else {
- return;
- }
- });
-
- let mut ctr_vis = ImplicitHasherConstructorVisitor::new(cx, target);
- for item in impl_.items.iter().map(|item| cx.tcx.hir().impl_item(item.id)) {
- ctr_vis.visit_impl_item(item);
- }
-
- span_lint_and_then(
- cx,
- IMPLICIT_HASHER,
- target.span(),
- &format!(
- "impl for `{}` should be generalized over different hashers",
- target.type_name()
- ),
- move |diag| {
- suggestion(cx, diag, impl_.generics.span, generics_suggestion_span, target, ctr_vis);
- },
- );
- }
- },
- ItemKind::Fn(ref sig, ref generics, body_id) => {
- let body = cx.tcx.hir().body(body_id);
-
- for ty in sig.decl.inputs {
- let mut vis = ImplicitHasherTypeVisitor::new(cx);
- vis.visit_ty(ty);
-
- for target in &vis.found {
- if in_external_macro(cx.sess(), generics.span) {
- continue;
- }
- let generics_suggestion_span = generics.span.substitute_dummy({
- let pos = snippet_opt(cx, item.span.until(body.params[0].pat.span))
- .and_then(|snip| {
- let i = snip.find("fn")?;
- Some(item.span.lo() + BytePos((i + (&snip[i..]).find('(')?) as u32))
- })
- .expect("failed to create span for type parameters");
- Span::new(pos, pos, item.span.data().ctxt)
- });
-
- let mut ctr_vis = ImplicitHasherConstructorVisitor::new(cx, target);
- ctr_vis.visit_body(body);
-
- span_lint_and_then(
- cx,
- IMPLICIT_HASHER,
- target.span(),
- &format!(
- "parameter of type `{}` should be generalized over different hashers",
- target.type_name()
- ),
- move |diag| {
- suggestion(cx, diag, generics.span, generics_suggestion_span, target, ctr_vis);
- },
- );
- }
+ self.check_ty(cx, ty, context);
}
},
_ => {},
}
}
-enum ImplicitHasherType<'tcx> {
- HashMap(Span, Ty<'tcx>, Cow<'static, str>, Cow<'static, str>),
- HashSet(Span, Ty<'tcx>, Cow<'static, str>),
-}
-
-impl<'tcx> ImplicitHasherType<'tcx> {
- /// Checks that `ty` is a target type without a `BuildHasher`.
- fn new(cx: &LateContext<'tcx>, hir_ty: &hir::Ty<'_>) -> Option<Self> {
- if let TyKind::Path(QPath::Resolved(None, ref path)) = hir_ty.kind {
- let params: Vec<_> = path
- .segments
- .last()
- .as_ref()?
- .args
- .as_ref()?
- .args
- .iter()
- .filter_map(|arg| match arg {
- GenericArg::Type(ty) => Some(ty),
- _ => None,
- })
- .collect();
- let params_len = params.len();
-
- let ty = hir_ty_to_ty(cx.tcx, hir_ty);
-
- if is_type_diagnostic_item(cx, ty, sym::hashmap_type) && params_len == 2 {
- Some(ImplicitHasherType::HashMap(
- hir_ty.span,
- ty,
- snippet(cx, params[0].span, "K"),
- snippet(cx, params[1].span, "V"),
- ))
- } else if is_type_diagnostic_item(cx, ty, sym::hashset_type) && params_len == 1 {
- Some(ImplicitHasherType::HashSet(
- hir_ty.span,
- ty,
- snippet(cx, params[0].span, "T"),
- ))
- } else {
- None
- }
- } else {
- None
- }
- }
-
- fn type_name(&self) -> &'static str {
- match *self {
- ImplicitHasherType::HashMap(..) => "HashMap",
- ImplicitHasherType::HashSet(..) => "HashSet",
- }
- }
-
- fn type_arguments(&self) -> String {
- match *self {
- ImplicitHasherType::HashMap(.., ref k, ref v) => format!("{}, {}", k, v),
- ImplicitHasherType::HashSet(.., ref t) => format!("{}", t),
- }
- }
-
- fn ty(&self) -> Ty<'tcx> {
- match *self {
- ImplicitHasherType::HashMap(_, ty, ..) | ImplicitHasherType::HashSet(_, ty, ..) => ty,
- }
- }
-
- fn span(&self) -> Span {
- match *self {
- ImplicitHasherType::HashMap(span, ..) | ImplicitHasherType::HashSet(span, ..) => span,
- }
- }
-}
-
-struct ImplicitHasherTypeVisitor<'a, 'tcx> {
- cx: &'a LateContext<'tcx>,
- found: Vec<ImplicitHasherType<'tcx>>,
-}
-
-impl<'a, 'tcx> ImplicitHasherTypeVisitor<'a, 'tcx> {
- fn new(cx: &'a LateContext<'tcx>) -> Self {
- Self { cx, found: vec![] }
- }
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for ImplicitHasherTypeVisitor<'a, 'tcx> {
- type Map = Map<'tcx>;
-
- fn visit_ty(&mut self, t: &'tcx hir::Ty<'_>) {
- if let Some(target) = ImplicitHasherType::new(self.cx, t) {
- self.found.push(target);
- }
-
- walk_ty(self, t);
- }
-
- fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
- NestedVisitorMap::None
- }
-}
-
-/// Looks for default-hasher-dependent constructors like `HashMap::new`.
-struct ImplicitHasherConstructorVisitor<'a, 'b, 'tcx> {
- cx: &'a LateContext<'tcx>,
- maybe_typeck_results: Option<&'tcx TypeckResults<'tcx>>,
- target: &'b ImplicitHasherType<'tcx>,
- suggestions: BTreeMap<Span, String>,
-}
-
-impl<'a, 'b, 'tcx> ImplicitHasherConstructorVisitor<'a, 'b, 'tcx> {
- fn new(cx: &'a LateContext<'tcx>, target: &'b ImplicitHasherType<'tcx>) -> Self {
- Self {
- cx,
- maybe_typeck_results: cx.maybe_typeck_results(),
- target,
- suggestions: BTreeMap::new(),
- }
- }
-}
-
-impl<'a, 'b, 'tcx> Visitor<'tcx> for ImplicitHasherConstructorVisitor<'a, 'b, 'tcx> {
- type Map = Map<'tcx>;
-
- fn visit_body(&mut self, body: &'tcx Body<'_>) {
- let old_maybe_typeck_results = self.maybe_typeck_results.replace(self.cx.tcx.typeck_body(body.id()));
- walk_body(self, body);
- self.maybe_typeck_results = old_maybe_typeck_results;
- }
-
- fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
- if_chain! {
- if let ExprKind::Call(ref fun, ref args) = e.kind;
- if let ExprKind::Path(QPath::TypeRelative(ref ty, ref method)) = fun.kind;
- if let TyKind::Path(QPath::Resolved(None, ty_path)) = ty.kind;
- then {
- if !TyS::same_type(self.target.ty(), self.maybe_typeck_results.unwrap().expr_ty(e)) {
- return;
- }
-
- if match_path(ty_path, &paths::HASHMAP) {
- if method.ident.name == sym::new {
- self.suggestions
- .insert(e.span, "HashMap::default()".to_string());
- } else if method.ident.name == sym!(with_capacity) {
- self.suggestions.insert(
- e.span,
- format!(
- "HashMap::with_capacity_and_hasher({}, Default::default())",
- snippet(self.cx, args[0].span, "capacity"),
- ),
- );
- }
- } else if match_path(ty_path, &paths::HASHSET) {
- if method.ident.name == sym::new {
- self.suggestions
- .insert(e.span, "HashSet::default()".to_string());
- } else if method.ident.name == sym!(with_capacity) {
- self.suggestions.insert(
- e.span,
- format!(
- "HashSet::with_capacity_and_hasher({}, Default::default())",
- snippet(self.cx, args[0].span, "capacity"),
- ),
- );
- }
- }
- }
- }
-
- walk_expr(self, e);
- }
-
- fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
- NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
- }
+#[derive(Clone, Copy, Default)]
+struct CheckTyContext {
+ is_in_trait_impl: bool,
+ is_local: bool,
+ is_nested_call: bool,
}
projects / rustc.git / blobdiff