-//! This module contains functions that retrieves specifiec elements.
+//! This module contains functions that retrieve specific elements.
#![deny(clippy::missing_docs_in_private_items)]
+use crate::consts::{constant_simple, Constant};
+use crate::ty::is_type_diagnostic_item;
use crate::{is_expn_of, match_def_path, paths};
use if_chain::if_chain;
-use rustc_ast::ast::{self, LitKind};
+use rustc_ast::ast;
use rustc_hir as hir;
-use rustc_hir::{Block, BorrowKind, Expr, ExprKind, LoopSource, Node, Pat, StmtKind, UnOp};
+use rustc_hir::{Arm, Block, Expr, ExprKind, HirId, LoopSource, MatchSource, Node, Pat, QPath};
use rustc_lint::LateContext;
-use rustc_span::{sym, ExpnKind, Span, Symbol};
+use rustc_span::{sym, symbol, Span};
/// The essential nodes of a desugared for loop as well as the entire span:
/// `for pat in arg { body }` becomes `(pat, arg, body)`. Return `(pat, arg, body, span)`.
pub struct ForLoop<'tcx> {
+ /// `for` loop item
pub pat: &'tcx hir::Pat<'tcx>,
+ /// `IntoIterator` argument
pub arg: &'tcx hir::Expr<'tcx>,
+ /// `for` loop body
pub body: &'tcx hir::Expr<'tcx>,
+ /// Compare this against `hir::Destination.target`
+ pub loop_id: HirId,
+ /// entire `for` loop span
pub span: Span,
}
impl<'tcx> ForLoop<'tcx> {
- #[inline]
+ /// Parses a desugared `for` loop
pub fn hir(expr: &Expr<'tcx>) -> Option<Self> {
if_chain! {
- if let hir::ExprKind::Match(ref iterexpr, ref arms, hir::MatchSource::ForLoopDesugar) = expr.kind;
- if let Some(first_arm) = arms.get(0);
- if let hir::ExprKind::Call(_, ref iterargs) = iterexpr.kind;
- if let Some(first_arg) = iterargs.get(0);
- if iterargs.len() == 1 && arms.len() == 1 && first_arm.guard.is_none();
- if let hir::ExprKind::Loop(ref block, ..) = first_arm.body.kind;
- if block.expr.is_none();
- if let [ _, _, ref let_stmt, ref body ] = *block.stmts;
- if let hir::StmtKind::Local(ref local) = let_stmt.kind;
- if let hir::StmtKind::Expr(ref body_expr) = body.kind;
+ if let hir::ExprKind::DropTemps(e) = expr.kind;
+ if let hir::ExprKind::Match(iterexpr, [arm], hir::MatchSource::ForLoopDesugar) = e.kind;
+ if let hir::ExprKind::Call(_, [arg]) = iterexpr.kind;
+ if let hir::ExprKind::Loop(block, ..) = arm.body.kind;
+ if let [stmt] = block.stmts;
+ if let hir::StmtKind::Expr(e) = stmt.kind;
+ if let hir::ExprKind::Match(_, [_, some_arm], _) = e.kind;
+ if let hir::PatKind::Struct(_, [field], _) = some_arm.pat.kind;
then {
return Some(Self {
- pat: &*local.pat,
- arg: first_arg,
- body: body_expr,
- span: first_arm.span
+ pat: field.pat,
+ arg,
+ body: some_arm.body,
+ loop_id: arm.body.hir_id,
+ span: expr.span.ctxt().outer_expn_data().call_site,
});
}
}
}
}
+/// An `if` expression without `DropTemps`
pub struct If<'hir> {
+ /// `if` condition
pub cond: &'hir Expr<'hir>,
- pub r#else: Option<&'hir Expr<'hir>>,
+ /// `if` then expression
pub then: &'hir Expr<'hir>,
+ /// `else` expression
+ pub r#else: Option<&'hir Expr<'hir>>,
}
impl<'hir> If<'hir> {
#[inline]
+ /// Parses an `if` expression
pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
if let ExprKind::If(
Expr {
r#else,
) = expr.kind
{
- Some(Self { cond, r#else, then })
+ Some(Self { cond, then, r#else })
} else {
None
}
}
}
+/// An `if let` expression
pub struct IfLet<'hir> {
+ /// `if let` pattern
pub let_pat: &'hir Pat<'hir>,
+ /// `if let` scrutinee
pub let_expr: &'hir Expr<'hir>,
+ /// `if let` then expression
pub if_then: &'hir Expr<'hir>,
+ /// `if let` else expression
pub if_else: Option<&'hir Expr<'hir>>,
}
impl<'hir> IfLet<'hir> {
- #[inline]
- pub fn ast(cx: &LateContext<'tcx>, expr: &Expr<'hir>) -> Option<Self> {
- let rslt = Self::hir(expr)?;
- Self::is_not_within_while_context(cx, expr)?;
- Some(rslt)
- }
-
- #[inline]
- pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+ /// Parses an `if let` expression
+ pub fn hir(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
if let ExprKind::If(
Expr {
- kind: ExprKind::Let(let_pat, let_expr, _),
+ kind:
+ ExprKind::Let(hir::Let {
+ pat: let_pat,
+ init: let_expr,
+ ..
+ }),
..
},
if_then,
if_else,
) = expr.kind
{
+ let mut iter = cx.tcx.hir().parent_iter(expr.hir_id);
+ if let Some((_, Node::Block(Block { stmts: [], .. }))) = iter.next() {
+ if let Some((
+ _,
+ Node::Expr(Expr {
+ kind: ExprKind::Loop(_, _, LoopSource::While, _),
+ ..
+ }),
+ )) = iter.next()
+ {
+ // while loop desugar
+ return None;
+ }
+ }
return Some(Self {
let_pat,
let_expr,
}
None
}
+}
- #[inline]
- fn is_not_within_while_context(cx: &LateContext<'tcx>, expr: &Expr<'hir>) -> Option<()> {
- let hir = cx.tcx.hir();
- let parent = hir.get_parent_node(expr.hir_id);
- let parent_parent = hir.get_parent_node(parent);
- let parent_parent_node = hir.get(parent_parent);
- if let Node::Expr(Expr {
- kind: ExprKind::Loop(_, _, LoopSource::While, _),
- ..
- }) = parent_parent_node
- {
- return None;
+/// An `if let` or `match` expression. Useful for lints that trigger on one or the other.
+pub enum IfLetOrMatch<'hir> {
+ /// Any `match` expression
+ Match(&'hir Expr<'hir>, &'hir [Arm<'hir>], MatchSource),
+ /// scrutinee, pattern, then block, else block
+ IfLet(
+ &'hir Expr<'hir>,
+ &'hir Pat<'hir>,
+ &'hir Expr<'hir>,
+ Option<&'hir Expr<'hir>>,
+ ),
+}
+
+impl<'hir> IfLetOrMatch<'hir> {
+ /// Parses an `if let` or `match` expression
+ pub fn parse(cx: &LateContext<'_>, expr: &Expr<'hir>) -> Option<Self> {
+ match expr.kind {
+ ExprKind::Match(expr, arms, source) => Some(Self::Match(expr, arms, source)),
+ _ => IfLet::hir(cx, expr).map(
+ |IfLet {
+ let_expr,
+ let_pat,
+ if_then,
+ if_else,
+ }| { Self::IfLet(let_expr, let_pat, if_then, if_else) },
+ ),
}
- Some(())
}
}
+/// An `if` or `if let` expression
pub struct IfOrIfLet<'hir> {
+ /// `if` condition that is maybe a `let` expression
pub cond: &'hir Expr<'hir>,
- pub r#else: Option<&'hir Expr<'hir>>,
+ /// `if` then expression
pub then: &'hir Expr<'hir>,
+ /// `else` expression
+ pub r#else: Option<&'hir Expr<'hir>>,
}
impl<'hir> IfOrIfLet<'hir> {
#[inline]
+ /// Parses an `if` or `if let` expression
pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
if let ExprKind::If(cond, then, r#else) = expr.kind {
if let ExprKind::DropTemps(new_cond) = cond.kind {
});
}
if let ExprKind::Let(..) = cond.kind {
- return Some(Self { cond, r#else, then });
+ return Some(Self { cond, then, r#else });
}
}
None
}
match expr.kind {
- hir::ExprKind::Call(ref path, ref args)
+ hir::ExprKind::Call(path, args)
if matches!(
path.kind,
- hir::ExprKind::Path(hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, _))
+ hir::ExprKind::Path(hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, ..))
) =>
{
Some(Range {
limits: ast::RangeLimits::Closed,
})
},
- hir::ExprKind::Struct(ref path, ref fields, None) => match path {
- hir::QPath::LangItem(hir::LangItem::RangeFull, _) => Some(Range {
+ hir::ExprKind::Struct(path, fields, None) => match &path {
+ hir::QPath::LangItem(hir::LangItem::RangeFull, ..) => Some(Range {
start: None,
end: None,
limits: ast::RangeLimits::HalfOpen,
}),
- hir::QPath::LangItem(hir::LangItem::RangeFrom, _) => Some(Range {
+ hir::QPath::LangItem(hir::LangItem::RangeFrom, ..) => Some(Range {
start: Some(get_field("start", fields)?),
end: None,
limits: ast::RangeLimits::HalfOpen,
}),
- hir::QPath::LangItem(hir::LangItem::Range, _) => Some(Range {
+ hir::QPath::LangItem(hir::LangItem::Range, ..) => Some(Range {
start: Some(get_field("start", fields)?),
end: Some(get_field("end", fields)?),
limits: ast::RangeLimits::HalfOpen,
}),
- hir::QPath::LangItem(hir::LangItem::RangeToInclusive, _) => Some(Range {
+ hir::QPath::LangItem(hir::LangItem::RangeToInclusive, ..) => Some(Range {
start: None,
end: Some(get_field("end", fields)?),
limits: ast::RangeLimits::Closed,
}),
- hir::QPath::LangItem(hir::LangItem::RangeTo, _) => Some(Range {
+ hir::QPath::LangItem(hir::LangItem::RangeTo, ..) => Some(Range {
start: None,
end: Some(get_field("end", fields)?),
limits: ast::RangeLimits::HalfOpen,
/// from `vec!`.
pub fn hir(cx: &LateContext<'_>, expr: &'a hir::Expr<'_>) -> Option<VecArgs<'a>> {
if_chain! {
- if let hir::ExprKind::Call(ref fun, ref args) = expr.kind;
+ if let hir::ExprKind::Call(fun, args) = expr.kind;
if let hir::ExprKind::Path(ref qpath) = fun.kind;
if is_expn_of(fun.span, "vec").is_some();
if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
return if match_def_path(cx, fun_def_id, &paths::VEC_FROM_ELEM) && args.len() == 2 {
// `vec![elem; size]` case
Some(VecArgs::Repeat(&args[0], &args[1]))
- }
- else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 {
+ } else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 {
// `vec![a, b, c]` case
if_chain! {
- if let hir::ExprKind::Box(ref boxed) = args[0].kind;
- if let hir::ExprKind::Array(ref args) = boxed.kind;
+ if let hir::ExprKind::Box(boxed) = args[0].kind;
+ if let hir::ExprKind::Array(args) = boxed.kind;
then {
- return Some(VecArgs::Vec(&*args));
+ return Some(VecArgs::Vec(args));
}
}
None
- }
- else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() {
+ } else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() {
Some(VecArgs::Vec(&[]))
- }
- else {
+ } else {
None
};
}
}
}
+/// A desugared `while` loop
pub struct While<'hir> {
- pub if_cond: &'hir Expr<'hir>,
- pub if_then: &'hir Expr<'hir>,
- pub if_else: Option<&'hir Expr<'hir>>,
+ /// `while` loop condition
+ pub condition: &'hir Expr<'hir>,
+ /// `while` loop body
+ pub body: &'hir Expr<'hir>,
}
impl<'hir> While<'hir> {
#[inline]
+ /// Parses a desugared `while` loop
pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
if let ExprKind::Loop(
Block {
kind:
ExprKind::If(
Expr {
- kind: ExprKind::DropTemps(if_cond),
+ kind: ExprKind::DropTemps(condition),
..
},
- if_then,
- if_else_ref,
+ body,
+ _,
),
..
}),
_,
) = expr.kind
{
- let if_else = *if_else_ref;
- return Some(Self {
- if_cond,
- if_then,
- if_else,
- });
+ return Some(Self { condition, body });
}
None
}
}
+/// A desugared `while let` loop
pub struct WhileLet<'hir> {
- pub if_expr: &'hir Expr<'hir>,
+ /// `while let` loop item pattern
pub let_pat: &'hir Pat<'hir>,
+ /// `while let` loop scrutinee
pub let_expr: &'hir Expr<'hir>,
+ /// `while let` loop body
pub if_then: &'hir Expr<'hir>,
- pub if_else: Option<&'hir Expr<'hir>>,
}
impl<'hir> WhileLet<'hir> {
#[inline]
+ /// Parses a desugared `while let` loop
pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
if let ExprKind::Loop(
Block {
- expr: Some(if_expr), ..
+ expr:
+ Some(Expr {
+ kind:
+ ExprKind::If(
+ Expr {
+ kind:
+ ExprKind::Let(hir::Let {
+ pat: let_pat,
+ init: let_expr,
+ ..
+ }),
+ ..
+ },
+ if_then,
+ _,
+ ),
+ ..
+ }),
+ ..
},
_,
LoopSource::While,
_,
) = expr.kind
{
- if let Expr {
- kind:
- ExprKind::If(
- Expr {
- kind: ExprKind::Let(let_pat, let_expr, _),
- ..
- },
- if_then,
- if_else_ref,
- ),
- ..
- } = if_expr
- {
- let if_else = *if_else_ref;
- return Some(Self {
- if_expr,
- let_pat,
- let_expr,
- if_then,
- if_else,
- });
- }
+ return Some(Self {
+ let_pat,
+ let_expr,
+ if_then,
+ });
}
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(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(block, _) = e.kind {
- if block.stmts.len() == 1 {
- if let StmtKind::Semi(matchexpr) = block.stmts.get(0)?.kind {
- // macros with unique arg: `{debug_}assert!` (e.g., `debug_assert!(some_condition)`)
- if_chain! {
- if let Some(If { cond, .. }) = If::hir(matchexpr);
- if let ExprKind::Unary(UnOp::Not, condition) = cond.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(matchblock,_) = matchexpr.kind;
- if let Some(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
-}
-
-/// A parsed `format!` expansion
-pub struct FormatExpn<'tcx> {
- /// Span of `format!(..)`
- pub call_site: Span,
- /// Inner `format_args!` expansion
- pub format_args: FormatArgsExpn<'tcx>,
+/// A parsed `Vec` initialization expression
+#[derive(Clone, Copy)]
+pub enum VecInitKind {
+ /// `Vec::new()`
+ New,
+ /// `Vec::default()` or `Default::default()`
+ Default,
+ /// `Vec::with_capacity(123)`
+ WithConstCapacity(u128),
+ /// `Vec::with_capacity(slice.len())`
+ WithExprCapacity(HirId),
}
-impl FormatExpn<'tcx> {
- /// Parses an expanded `format!` invocation
- pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
- if_chain! {
- if let ExprKind::Block(block, _) = expr.kind;
- if let [stmt] = block.stmts;
- if let StmtKind::Local(local) = stmt.kind;
- if let Some(init) = local.init;
- if let ExprKind::Call(_, [format_args]) = init.kind;
- let expn_data = expr.span.ctxt().outer_expn_data();
- if let ExpnKind::Macro(_, sym::format) = expn_data.kind;
- if let Some(format_args) = FormatArgsExpn::parse(format_args);
- then {
- Some(FormatExpn {
- call_site: expn_data.call_site,
- format_args,
- })
- } else {
- None
- }
- }
- }
-}
-
-/// A parsed `format_args!` expansion
-pub struct FormatArgsExpn<'tcx> {
- /// Span of the first argument, the format string
- pub format_string_span: Span,
- /// Values passed after the format string
- pub value_args: Vec<&'tcx Expr<'tcx>>,
-
- /// String literal expressions which represent the format string split by "{}"
- pub format_string_parts: &'tcx [Expr<'tcx>],
- /// Symbols corresponding to [`Self::format_string_parts`]
- pub format_string_symbols: Vec<Symbol>,
- /// Expressions like `ArgumentV1::new(arg0, Debug::fmt)`
- pub args: &'tcx [Expr<'tcx>],
- /// The final argument passed to `Arguments::new_v1_formatted`, if applicable
- pub fmt_expr: Option<&'tcx Expr<'tcx>>,
-}
-
-impl FormatArgsExpn<'tcx> {
- /// Parses an expanded `format_args!` or `format_args_nl!` invocation
- pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
- if_chain! {
- if let ExpnKind::Macro(_, name) = expr.span.ctxt().outer_expn_data().kind;
- let name = name.as_str();
- if name.ends_with("format_args") || name.ends_with("format_args_nl");
- if let ExprKind::Call(_, args) = expr.kind;
- if let Some((strs_ref, args, fmt_expr)) = match args {
- // Arguments::new_v1
- [strs_ref, args] => Some((strs_ref, args, None)),
- // Arguments::new_v1_formatted
- [strs_ref, args, fmt_expr] => Some((strs_ref, args, Some(fmt_expr))),
- _ => None,
- };
- if let ExprKind::AddrOf(BorrowKind::Ref, _, strs_arr) = strs_ref.kind;
- if let ExprKind::Array(format_string_parts) = strs_arr.kind;
- if let Some(format_string_symbols) = format_string_parts
- .iter()
- .map(|e| {
- if let ExprKind::Lit(lit) = &e.kind {
- if let LitKind::Str(symbol, _style) = lit.node {
- return Some(symbol);
- }
- }
- None
- })
- .collect();
- if let ExprKind::AddrOf(BorrowKind::Ref, _, args) = args.kind;
- if let ExprKind::Match(args, [arm], _) = args.kind;
- if let ExprKind::Tup(value_args) = args.kind;
- if let Some(value_args) = value_args
- .iter()
- .map(|e| match e.kind {
- ExprKind::AddrOf(_, _, e) => Some(e),
- _ => None,
- })
- .collect();
- if let ExprKind::Array(args) = arm.body.kind;
- then {
- Some(FormatArgsExpn {
- format_string_span: strs_ref.span,
- value_args,
- format_string_parts,
- format_string_symbols,
- args,
- fmt_expr,
- })
- } else {
- None
- }
- }
- }
-}
-
-/// Checks if a `let` statement is from a `for` loop desugaring.
-pub fn is_from_for_desugar(local: &hir::Local<'_>) -> bool {
- // This will detect plain for-loops without an actual variable binding:
- //
- // ```
- // for x in some_vec {
- // // do stuff
- // }
- // ```
- if_chain! {
- if let Some(ref expr) = local.init;
- if let hir::ExprKind::Match(_, _, hir::MatchSource::ForLoopDesugar) = expr.kind;
- then {
- return true;
+/// Checks if given expression is an initialization of `Vec` and returns its kind.
+pub fn get_vec_init_kind<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<VecInitKind> {
+ if let ExprKind::Call(func, args) = expr.kind {
+ match func.kind {
+ ExprKind::Path(QPath::TypeRelative(ty, name))
+ if is_type_diagnostic_item(cx, cx.typeck_results().node_type(ty.hir_id), sym::Vec) =>
+ {
+ if name.ident.name == sym::new {
+ return Some(VecInitKind::New);
+ } else if name.ident.name == symbol::kw::Default {
+ return Some(VecInitKind::Default);
+ } else if name.ident.name.as_str() == "with_capacity" {
+ let arg = args.get(0)?;
+ return match constant_simple(cx, cx.typeck_results(), arg) {
+ Some(Constant::Int(num)) => Some(VecInitKind::WithConstCapacity(num)),
+ _ => Some(VecInitKind::WithExprCapacity(arg.hir_id)),
+ };
+ };
+ },
+ ExprKind::Path(QPath::Resolved(_, path))
+ if match_def_path(cx, path.res.opt_def_id()?, &paths::DEFAULT_TRAIT_METHOD)
+ && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::Vec) =>
+ {
+ return Some(VecInitKind::Default);
+ },
+ _ => (),
}
}
-
- // This detects a variable binding in for loop to avoid `let_unit_value`
- // lint (see issue #1964).
- //
- // ```
- // for _ in vec![()] {
- // // anything
- // }
- // ```
- if let hir::LocalSource::ForLoopDesugar = local.source {
- return true;
- }
-
- false
+ None
}
projects / rust.git / blobdiff