-//! 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, last_path_segment, match_def_path, paths};
+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::{
- Arm, Block, BorrowKind, Expr, ExprKind, HirId, LoopSource, MatchSource, Node, Pat, QPath, StmtKind, UnOp,
-};
+use rustc_hir::{Arm, Block, Expr, ExprKind, HirId, LoopSource, MatchSource, Node, Pat, QPath};
use rustc_lint::LateContext;
-use rustc_span::{sym, symbol, 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 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(iterexpr, arms, hir::MatchSource::ForLoopDesugar) = expr.kind;
- if let Some(first_arm) = arms.get(0);
- if let hir::ExprKind::Call(_, 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(block, ..) = first_arm.body.kind;
- if block.expr.is_none();
- if let [ _, _, ref let_stmt, ref body ] = *block.stmts;
- if let hir::StmtKind::Local(local) = let_stmt.kind;
- if let hir::StmtKind::Expr(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,
});
}
}
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,
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 {
})
},
hir::ExprKind::Struct(path, fields, None) => match &path {
- hir::QPath::LangItem(hir::LangItem::RangeFull, _) => Some(Range {
+ 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,
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(boxed) = args[0].kind;
}
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
};
}
kind:
ExprKind::If(
Expr {
- kind: ExprKind::Let(let_pat, let_expr, _),
+ kind:
+ ExprKind::Let(hir::Let {
+ pat: let_pat,
+ init: let_expr,
+ ..
+ }),
..
},
if_then,
}
}
-/// 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>,
-}
-
-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, _unsafe_arg] => 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
- }
- }
- }
-
- /// Returns a vector of `FormatArgsArg`.
- pub fn args(&self) -> Option<Vec<FormatArgsArg<'tcx>>> {
- if let Some(expr) = self.fmt_expr {
- if_chain! {
- if let ExprKind::AddrOf(BorrowKind::Ref, _, expr) = expr.kind;
- if let ExprKind::Array(exprs) = expr.kind;
- then {
- exprs.iter().map(|fmt| {
- if_chain! {
- // struct `core::fmt::rt::v1::Argument`
- if let ExprKind::Struct(_, fields, _) = fmt.kind;
- if let Some(position_field) = fields.iter().find(|f| f.ident.name == sym::position);
- if let ExprKind::Lit(lit) = &position_field.expr.kind;
- if let LitKind::Int(position, _) = lit.node;
- then {
- let i = usize::try_from(position).unwrap();
- Some(FormatArgsArg { value: self.value_args[i], arg: &self.args[i], fmt: Some(fmt) })
- } else {
- None
- }
- }
- }).collect()
- } else {
- None
- }
- }
- } else {
- Some(
- self.value_args
- .iter()
- .zip(self.args.iter())
- .map(|(value, arg)| FormatArgsArg { value, arg, fmt: None })
- .collect(),
- )
- }
- }
-}
-
-/// Type representing a `FormatArgsExpn`'s format arguments
-pub struct FormatArgsArg<'tcx> {
- /// An element of `value_args` according to `position`
- pub value: &'tcx Expr<'tcx>,
- /// An element of `args` according to `position`
- pub arg: &'tcx Expr<'tcx>,
- /// An element of `fmt_expn`
- pub fmt: Option<&'tcx Expr<'tcx>>,
-}
-
-impl<'tcx> FormatArgsArg<'tcx> {
- /// Returns true if any formatting parameters are used that would have an effect on strings,
- /// like `{:+2}` instead of just `{}`.
- pub fn has_string_formatting(&self) -> bool {
- self.fmt.map_or(false, |fmt| {
- // `!` because these conditions check that `self` is unformatted.
- !if_chain! {
- // struct `core::fmt::rt::v1::Argument`
- if let ExprKind::Struct(_, fields, _) = fmt.kind;
- if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
- // struct `core::fmt::rt::v1::FormatSpec`
- if let ExprKind::Struct(_, subfields, _) = format_field.expr.kind;
- let mut precision_found = false;
- let mut width_found = false;
- if subfields.iter().all(|field| {
- match field.ident.name {
- sym::precision => {
- precision_found = true;
- if let ExprKind::Path(ref precision_path) = field.expr.kind {
- last_path_segment(precision_path).ident.name == sym::Implied
- } else {
- false
- }
- }
- sym::width => {
- width_found = true;
- if let ExprKind::Path(ref width_qpath) = field.expr.kind {
- last_path_segment(width_qpath).ident.name == sym::Implied
- } else {
- false
- }
- }
- _ => true,
- }
- });
- if precision_found && width_found;
- then { true } else { false }
- }
- })
- }
-
- /// Returns true if the argument is formatted using `Display::fmt`.
- pub fn is_display(&self) -> bool {
- if_chain! {
- if let ExprKind::Call(_, [_, format_field]) = self.arg.kind;
- if let ExprKind::Path(QPath::Resolved(_, path)) = format_field.kind;
- if let [.., t, _] = path.segments;
- if t.ident.name == sym::Display;
- then { true } else { false }
- }
- }
-}
-
-/// 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(expr) = local.init;
- if let hir::ExprKind::Match(_, _, hir::MatchSource::ForLoopDesugar) = expr.kind;
- then {
- return true;
- }
- }
-
- // 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
-}
-
-/// A parsed `panic!` expansion
-pub struct PanicExpn<'tcx> {
- /// Span of `panic!(..)`
- pub call_site: Span,
- /// Inner `format_args!` expansion
- pub format_args: FormatArgsExpn<'tcx>,
-}
-
-impl PanicExpn<'tcx> {
- /// Parses an expanded `panic!` invocation
- pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
- if_chain! {
- if let ExprKind::Block(block, _) = expr.kind;
- if let Some(init) = block.expr;
- if let ExprKind::Call(_, [format_args]) = init.kind;
- let expn_data = expr.span.ctxt().outer_expn_data();
- if let Some(format_args) = FormatArgsExpn::parse(format_args);
- then {
- Some(PanicExpn {
- call_site: expn_data.call_site,
- format_args,
- })
- } else {
- None
- }
- }
- }
-}
-
/// A parsed `Vec` initialization expression
#[derive(Clone, Copy)]
pub enum VecInitKind {
/// `Vec::default()` or `Default::default()`
Default,
/// `Vec::with_capacity(123)`
- WithLiteralCapacity(u64),
+ WithConstCapacity(u128),
/// `Vec::with_capacity(slice.len())`
WithExprCapacity(HirId),
}
return Some(VecInitKind::Default);
} else if name.ident.name.as_str() == "with_capacity" {
let arg = args.get(0)?;
- if_chain! {
- if let ExprKind::Lit(lit) = &arg.kind;
- if let LitKind::Int(num, _) = lit.node;
- then {
- return Some(VecInitKind::WithLiteralCapacity(num.try_into().ok()?))
- }
- }
- return Some(VecInitKind::WithExprCapacity(arg.hir_id));
- }
- }
+ 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);
- }
+ },
_ => (),
}
}