diff options
Diffstat (limited to 'src/tools/clippy/clippy_utils/src/macros.rs')
| -rw-r--r-- | src/tools/clippy/clippy_utils/src/macros.rs | 832 |
1 files changed, 140 insertions, 692 deletions
diff --git a/src/tools/clippy/clippy_utils/src/macros.rs b/src/tools/clippy/clippy_utils/src/macros.rs index be6133d32..62d388a5e 100644 --- a/src/tools/clippy/clippy_utils/src/macros.rs +++ b/src/tools/clippy/clippy_utils/src/macros.rs @@ -1,22 +1,18 @@ #![allow(clippy::similar_names)] // `expr` and `expn` -use crate::source::snippet_opt; use crate::visitors::{for_each_expr, Descend}; use arrayvec::ArrayVec; -use itertools::{izip, Either, Itertools}; -use rustc_ast::ast::LitKind; -use rustc_hir::intravisit::{walk_expr, Visitor}; -use rustc_hir::{self as hir, Expr, ExprField, ExprKind, HirId, LangItem, Node, QPath, TyKind}; -use rustc_lexer::unescape::unescape_literal; -use rustc_lexer::{tokenize, unescape, LiteralKind, TokenKind}; +use rustc_ast::{FormatArgs, FormatArgument, FormatPlaceholder}; +use rustc_data_structures::fx::FxHashMap; +use rustc_hir::{self as hir, Expr, ExprKind, HirId, Node, QPath}; use rustc_lint::LateContext; -use rustc_parse_format::{self as rpf, Alignment}; use rustc_span::def_id::DefId; use rustc_span::hygiene::{self, MacroKind, SyntaxContext}; -use rustc_span::{sym, BytePos, ExpnData, ExpnId, ExpnKind, Pos, Span, SpanData, Symbol}; -use std::iter::{once, zip}; +use rustc_span::{sym, BytePos, ExpnData, ExpnId, ExpnKind, Span, Symbol}; +use std::cell::RefCell; use std::ops::ControlFlow; +use std::sync::atomic::{AtomicBool, Ordering}; const FORMAT_MACRO_DIAG_ITEMS: &[Symbol] = &[ sym::assert_eq_macro, @@ -213,6 +209,7 @@ pub fn is_assert_macro(cx: &LateContext<'_>, def_id: DefId) -> bool { matches!(name, sym::assert_macro | sym::debug_assert_macro) } +#[derive(Debug)] pub enum PanicExpn<'a> { /// No arguments - `panic!()` Empty, @@ -221,15 +218,12 @@ pub enum PanicExpn<'a> { /// A single argument that implements `Display` - `panic!("{}", object)` Display(&'a Expr<'a>), /// Anything else - `panic!("error {}: {}", a, b)` - Format(FormatArgsExpn<'a>), + Format(&'a Expr<'a>), } impl<'a> PanicExpn<'a> { - pub fn parse(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<Self> { - if !macro_backtrace(expr.span).any(|macro_call| is_panic(cx, macro_call.def_id)) { - return None; - } - let ExprKind::Call(callee, [arg]) = &expr.kind else { return None }; + pub fn parse(expr: &'a Expr<'a>) -> Option<Self> { + let ExprKind::Call(callee, [arg, rest @ ..]) = &expr.kind else { return None }; let ExprKind::Path(QPath::Resolved(_, path)) = &callee.kind else { return None }; let result = match path.segments.last().unwrap().ident.as_str() { "panic" if arg.span.ctxt() == expr.span.ctxt() => Self::Empty, @@ -238,7 +232,22 @@ impl<'a> PanicExpn<'a> { let ExprKind::AddrOf(_, _, e) = &arg.kind else { return None }; Self::Display(e) }, - "panic_fmt" => Self::Format(FormatArgsExpn::parse(cx, arg)?), + "panic_fmt" => Self::Format(arg), + // Since Rust 1.52, `assert_{eq,ne}` macros expand to use: + // `core::panicking::assert_failed(.., left_val, right_val, None | Some(format_args!(..)));` + "assert_failed" => { + // It should have 4 arguments in total (we already matched with the first argument, + // so we're just checking for 3) + if rest.len() != 3 { + return None; + } + // `msg_arg` is either `None` (no custom message) or `Some(format_args!(..))` (custom message) + let msg_arg = &rest[2]; + match msg_arg.kind { + ExprKind::Call(_, [fmt_arg]) => Self::Format(fmt_arg), + _ => Self::Empty, + } + }, _ => return None, }; Some(result) @@ -251,7 +260,17 @@ pub fn find_assert_args<'a>( expr: &'a Expr<'a>, expn: ExpnId, ) -> Option<(&'a Expr<'a>, PanicExpn<'a>)> { - find_assert_args_inner(cx, expr, expn).map(|([e], p)| (e, p)) + find_assert_args_inner(cx, expr, expn).map(|([e], mut p)| { + // `assert!(..)` expands to `core::panicking::panic("assertion failed: ...")` (which we map to + // `PanicExpn::Str(..)`) and `assert!(.., "..")` expands to + // `core::panicking::panic_fmt(format_args!(".."))` (which we map to `PanicExpn::Format(..)`). + // So even we got `PanicExpn::Str(..)` that means there is no custom message provided + if let PanicExpn::Str(_) = p { + p = PanicExpn::Empty; + } + + (e, p) + }) } /// Finds the arguments of an `assert_eq!` or `debug_assert_eq!` macro call within the macro @@ -275,13 +294,12 @@ fn find_assert_args_inner<'a, const N: usize>( Some(inner_name) => find_assert_within_debug_assert(cx, expr, expn, Symbol::intern(inner_name))?, }; let mut args = ArrayVec::new(); - let mut panic_expn = None; - let _: Option<!> = for_each_expr(expr, |e| { + let panic_expn = for_each_expr(expr, |e| { if args.is_full() { - if panic_expn.is_none() && e.span.ctxt() != expr.span.ctxt() { - panic_expn = PanicExpn::parse(cx, e); + match PanicExpn::parse(e) { + Some(expn) => ControlFlow::Break(expn), + None => ControlFlow::Continue(Descend::Yes), } - ControlFlow::Continue(Descend::from(panic_expn.is_none())) } else if is_assert_arg(cx, e, expn) { args.push(e); ControlFlow::Continue(Descend::No) @@ -339,241 +357,127 @@ fn is_assert_arg(cx: &LateContext<'_>, expr: &Expr<'_>, assert_expn: ExpnId) -> } } -/// The format string doesn't exist in the HIR, so we reassemble it from source code -#[derive(Debug)] -pub struct FormatString { - /// Span of the whole format string literal, including `[r#]"`. - pub span: Span, - /// Snippet of the whole format string literal, including `[r#]"`. - pub snippet: String, - /// If the string is raw `r"..."`/`r#""#`, how many `#`s does it have on each side. - pub style: Option<usize>, - /// The unescaped value of the format string, e.g. `"val – {}"` for the literal - /// `"val \u{2013} {}"`. - pub unescaped: String, - /// The format string split by format args like `{..}`. - pub parts: Vec<Symbol>, +thread_local! { + /// We preserve the [`FormatArgs`] structs from the early pass for use in the late pass to be + /// able to access the many features of a [`LateContext`]. + /// + /// A thread local is used because [`FormatArgs`] is `!Send` and `!Sync`, we are making an + /// assumption that the early pass the populates the map and the later late passes will all be + /// running on the same thread. + static AST_FORMAT_ARGS: RefCell<FxHashMap<Span, FormatArgs>> = { + static CALLED: AtomicBool = AtomicBool::new(false); + debug_assert!( + !CALLED.swap(true, Ordering::SeqCst), + "incorrect assumption: `AST_FORMAT_ARGS` should only be accessed by a single thread", + ); + + RefCell::default() + }; } -impl FormatString { - fn new(cx: &LateContext<'_>, pieces: &Expr<'_>) -> Option<Self> { - // format_args!(r"a {} b \", 1); - // - // expands to - // - // ::core::fmt::Arguments::new_v1(&["a ", " b \\"], - // &[::core::fmt::ArgumentV1::new_display(&1)]); - // - // where `pieces` is the expression `&["a ", " b \\"]`. It has the span of `r"a {} b \"` - let span = pieces.span; - let snippet = snippet_opt(cx, span)?; - - let (inner, style) = match tokenize(&snippet).next()?.kind { - TokenKind::Literal { kind, .. } => { - let style = match kind { - LiteralKind::Str { .. } => None, - LiteralKind::RawStr { n_hashes: Some(n), .. } => Some(n.into()), - _ => return None, - }; - - let start = style.map_or(1, |n| 2 + n); - let end = snippet.len() - style.map_or(1, |n| 1 + n); - - (&snippet[start..end], style) - }, - _ => return None, - }; +/// Record [`rustc_ast::FormatArgs`] for use in late lint passes, this should only be called by +/// `FormatArgsCollector` +pub fn collect_ast_format_args(span: Span, format_args: &FormatArgs) { + AST_FORMAT_ARGS.with(|ast_format_args| { + ast_format_args.borrow_mut().insert(span, format_args.clone()); + }); +} - let mode = if style.is_some() { - unescape::Mode::RawStr +/// Calls `callback` with an AST [`FormatArgs`] node if a `format_args` expansion is found as a +/// descendant of `expn_id` +pub fn find_format_args(cx: &LateContext<'_>, start: &Expr<'_>, expn_id: ExpnId, callback: impl FnOnce(&FormatArgs)) { + let format_args_expr = for_each_expr(start, |expr| { + let ctxt = expr.span.ctxt(); + if ctxt.outer_expn().is_descendant_of(expn_id) { + if macro_backtrace(expr.span) + .map(|macro_call| cx.tcx.item_name(macro_call.def_id)) + .any(|name| matches!(name, sym::const_format_args | sym::format_args | sym::format_args_nl)) + { + ControlFlow::Break(expr) + } else { + ControlFlow::Continue(Descend::Yes) + } } else { - unescape::Mode::Str - }; - - let mut unescaped = String::with_capacity(inner.len()); - // Sometimes the original string comes from a macro which accepts a malformed string, such as in a - // #[display(""somestring)] attribute (accepted by the `displaythis` crate). Reconstructing the - // string from the span will not be possible, so we will just return None here. - let mut unparsable = false; - unescape_literal(inner, mode, &mut |_, ch| match ch { - Ok(ch) => unescaped.push(ch), - Err(e) if !e.is_fatal() => (), - Err(_) => unparsable = true, - }); - if unparsable { - return None; + ControlFlow::Continue(Descend::No) } + }); - let mut parts = Vec::new(); - let _: Option<!> = for_each_expr(pieces, |expr| { - if let ExprKind::Lit(lit) = &expr.kind - && let LitKind::Str(symbol, _) = lit.node - { - parts.push(symbol); - } - ControlFlow::Continue(()) + if let Some(expr) = format_args_expr { + AST_FORMAT_ARGS.with(|ast_format_args| { + ast_format_args.borrow().get(&expr.span).map(callback); }); - - Some(Self { - span, - snippet, - style, - unescaped, - parts, - }) } } -struct FormatArgsValues<'tcx> { - /// Values passed after the format string and implicit captures. `[1, z + 2, x]` for - /// `format!("{x} {} {}", 1, z + 2)`. - value_args: Vec<&'tcx Expr<'tcx>>, - /// Maps an `rt::v1::Argument::position` or an `rt::v1::Count::Param` to its index in - /// `value_args` - pos_to_value_index: Vec<usize>, - /// Used to check if a value is declared inline & to resolve `InnerSpan`s. - format_string_span: SpanData, -} - -impl<'tcx> FormatArgsValues<'tcx> { - fn new(args: &'tcx Expr<'tcx>, format_string_span: SpanData) -> Self { - let mut pos_to_value_index = Vec::new(); - let mut value_args = Vec::new(); - let _: Option<!> = for_each_expr(args, |expr| { - if expr.span.ctxt() == args.span.ctxt() { - // ArgumentV1::new_<format_trait>(<val>) - // ArgumentV1::from_usize(<val>) - if let ExprKind::Call(callee, [val]) = expr.kind - && let ExprKind::Path(QPath::TypeRelative(ty, _)) = callee.kind - && let TyKind::Path(QPath::LangItem(LangItem::FormatArgument, _, _)) = ty.kind - { - let val_idx = if val.span.ctxt() == expr.span.ctxt() - && let ExprKind::Field(_, field) = val.kind - && let Ok(idx) = field.name.as_str().parse() - { - // tuple index - idx - } else { - // assume the value expression is passed directly - pos_to_value_index.len() - }; - - pos_to_value_index.push(val_idx); - } - ControlFlow::Continue(Descend::Yes) - } else { - // assume that any expr with a differing span is a value - value_args.push(expr); - ControlFlow::Continue(Descend::No) - } - }); - - Self { - value_args, - pos_to_value_index, - format_string_span, +/// Attempt to find the [`rustc_hir::Expr`] that corresponds to the [`FormatArgument`]'s value, if +/// it cannot be found it will return the [`rustc_ast::Expr`]. +pub fn find_format_arg_expr<'hir, 'ast>( + start: &'hir Expr<'hir>, + target: &'ast FormatArgument, +) -> Result<&'hir rustc_hir::Expr<'hir>, &'ast rustc_ast::Expr> { + for_each_expr(start, |expr| { + if expr.span == target.expr.span { + ControlFlow::Break(expr) + } else { + ControlFlow::Continue(()) } - } + }) + .ok_or(&target.expr) } -/// The positions of a format argument's value, precision and width +/// Span of the `:` and format specifiers /// -/// A position is an index into the second argument of `Arguments::new_v1[_formatted]` -#[derive(Debug, Default, Copy, Clone)] -struct ParamPosition { - /// The position stored in `rt::v1::Argument::position`. - value: usize, - /// The position stored in `rt::v1::FormatSpec::width` if it is a `Count::Param`. - width: Option<usize>, - /// The position stored in `rt::v1::FormatSpec::precision` if it is a `Count::Param`. - precision: Option<usize>, +/// ```ignore +/// format!("{:.}"), format!("{foo:.}") +/// ^^ ^^ +/// ``` +pub fn format_placeholder_format_span(placeholder: &FormatPlaceholder) -> Option<Span> { + let base = placeholder.span?.data(); + + // `base.hi` is `{...}|`, subtract 1 byte (the length of '}') so that it points before the closing + // brace `{...|}` + Some(Span::new( + placeholder.argument.span?.hi(), + base.hi - BytePos(1), + base.ctxt, + base.parent, + )) } -impl<'tcx> Visitor<'tcx> for ParamPosition { - fn visit_expr_field(&mut self, field: &'tcx ExprField<'tcx>) { - match field.ident.name { - sym::position => { - if let ExprKind::Lit(lit) = &field.expr.kind - && let LitKind::Int(pos, _) = lit.node - { - self.value = pos as usize; - } - }, - sym::precision => { - self.precision = parse_count(field.expr); - }, - sym::width => { - self.width = parse_count(field.expr); - }, - _ => walk_expr(self, field.expr), - } +/// Span covering the format string and values +/// +/// ```ignore +/// format("{}.{}", 10, 11) +/// // ^^^^^^^^^^^^^^^ +/// ``` +pub fn format_args_inputs_span(format_args: &FormatArgs) -> Span { + match format_args.arguments.explicit_args() { + [] => format_args.span, + [.., last] => format_args + .span + .to(hygiene::walk_chain(last.expr.span, format_args.span.ctxt())), } } -fn parse_count(expr: &Expr<'_>) -> Option<usize> { - // <::core::fmt::rt::v1::Count>::Param(1usize), - if let ExprKind::Call(ctor, [val]) = expr.kind - && let ExprKind::Path(QPath::TypeRelative(_, path)) = ctor.kind - && path.ident.name == sym::Param - && let ExprKind::Lit(lit) = &val.kind - && let LitKind::Int(pos, _) = lit.node - { - Some(pos as usize) - } else { - None - } -} +/// Returns the [`Span`] of the value at `index` extended to the previous comma, e.g. for the value +/// `10` +/// +/// ```ignore +/// format("{}.{}", 10, 11) +/// // ^^^^ +/// ``` +pub fn format_arg_removal_span(format_args: &FormatArgs, index: usize) -> Option<Span> { + let ctxt = format_args.span.ctxt(); -/// Parses the `fmt` arg of `Arguments::new_v1_formatted(pieces, args, fmt, _)` -fn parse_rt_fmt<'tcx>(fmt_arg: &'tcx Expr<'tcx>) -> Option<impl Iterator<Item = ParamPosition> + 'tcx> { - if let ExprKind::AddrOf(.., array) = fmt_arg.kind - && let ExprKind::Array(specs) = array.kind - { - Some(specs.iter().map(|spec| { - if let ExprKind::Call(f, args) = spec.kind - && let ExprKind::Path(QPath::TypeRelative(ty, f)) = f.kind - && let TyKind::Path(QPath::LangItem(LangItem::FormatPlaceholder, _, _)) = ty.kind - && f.ident.name == sym::new - && let [position, _fill, _align, _flags, precision, width] = args - && let ExprKind::Lit(position) = &position.kind - && let LitKind::Int(position, _) = position.node { - ParamPosition { - value: position as usize, - width: parse_count(width), - precision: parse_count(precision), - } - } else { - ParamPosition::default() - } - })) - } else { - None - } -} + let current = hygiene::walk_chain(format_args.arguments.by_index(index)?.expr.span, ctxt); -/// `Span::from_inner`, but for `rustc_parse_format`'s `InnerSpan` -fn span_from_inner(base: SpanData, inner: rpf::InnerSpan) -> Span { - Span::new( - base.lo + BytePos::from_usize(inner.start), - base.lo + BytePos::from_usize(inner.end), - base.ctxt, - base.parent, - ) -} + let prev = if index == 0 { + format_args.span + } else { + hygiene::walk_chain(format_args.arguments.by_index(index - 1)?.expr.span, ctxt) + }; -/// How a format parameter is used in the format string -#[derive(Debug, Copy, Clone, PartialEq, Eq)] -pub enum FormatParamKind { - /// An implicit parameter , such as `{}` or `{:?}`. - Implicit, - /// A parameter with an explicit number, e.g. `{1}`, `{0:?}`, or `{:.0$}` - Numbered, - /// A parameter with an asterisk precision. e.g. `{:.*}`. - Starred, - /// A named parameter with a named `value_arg`, such as the `x` in `format!("{x}", x = 1)`. - Named(Symbol), - /// An implicit named parameter, such as the `y` in `format!("{y}")`. - NamedInline(Symbol), + Some(current.with_lo(prev.hi())) } /// Where a format parameter is being used in the format string @@ -587,462 +491,6 @@ pub enum FormatParamUsage { Precision, } -/// A `FormatParam` is any place in a `FormatArgument` that refers to a supplied value, e.g. -/// -/// ``` -/// let precision = 2; -/// format!("{:.precision$}", 0.1234); -/// ``` -/// -/// has two `FormatParam`s, a [`FormatParamKind::Implicit`] `.kind` with a `.value` of `0.1234` -/// and a [`FormatParamKind::NamedInline("precision")`] `.kind` with a `.value` of `2` -#[derive(Debug, Copy, Clone)] -pub struct FormatParam<'tcx> { - /// The expression this parameter refers to. - pub value: &'tcx Expr<'tcx>, - /// How this parameter refers to its `value`. - pub kind: FormatParamKind, - /// Where this format param is being used - argument/width/precision - pub usage: FormatParamUsage, - /// Span of the parameter, may be zero width. Includes the whitespace of implicit parameters. - /// - /// ```text - /// format!("{}, { }, {0}, {name}", ...); - /// ^ ~~ ~ ~~~~ - /// ``` - pub span: Span, -} - -impl<'tcx> FormatParam<'tcx> { - fn new( - mut kind: FormatParamKind, - usage: FormatParamUsage, - position: usize, - inner: rpf::InnerSpan, - values: &FormatArgsValues<'tcx>, - ) -> Option<Self> { - let value_index = *values.pos_to_value_index.get(position)?; - let value = *values.value_args.get(value_index)?; - let span = span_from_inner(values.format_string_span, inner); - - // if a param is declared inline, e.g. `format!("{x}")`, the generated expr's span points - // into the format string - if let FormatParamKind::Named(name) = kind && values.format_string_span.contains(value.span.data()) { - kind = FormatParamKind::NamedInline(name); - } - - Some(Self { - value, - kind, - usage, - span, - }) - } -} - -/// Used by [width](https://doc.rust-lang.org/std/fmt/#width) and -/// [precision](https://doc.rust-lang.org/std/fmt/#precision) specifiers. -#[derive(Debug, Copy, Clone)] -pub enum Count<'tcx> { - /// Specified with a literal number, stores the value. - Is(usize, Span), - /// Specified using `$` and `*` syntaxes. The `*` format is still considered to be - /// `FormatParamKind::Numbered`. - Param(FormatParam<'tcx>), - /// Not specified. - Implied(Option<Span>), -} - -impl<'tcx> Count<'tcx> { - fn new( - usage: FormatParamUsage, - count: rpf::Count<'_>, - position: Option<usize>, - inner: Option<rpf::InnerSpan>, - values: &FormatArgsValues<'tcx>, - ) -> Option<Self> { - let span = inner.map(|inner| span_from_inner(values.format_string_span, inner)); - - Some(match count { - rpf::Count::CountIs(val) => Self::Is(val, span?), - rpf::Count::CountIsName(name, _) => Self::Param(FormatParam::new( - FormatParamKind::Named(Symbol::intern(name)), - usage, - position?, - inner?, - values, - )?), - rpf::Count::CountIsParam(_) => Self::Param(FormatParam::new( - FormatParamKind::Numbered, - usage, - position?, - inner?, - values, - )?), - rpf::Count::CountIsStar(_) => Self::Param(FormatParam::new( - FormatParamKind::Starred, - usage, - position?, - inner?, - values, - )?), - rpf::Count::CountImplied => Self::Implied(span), - }) - } - - pub fn is_implied(self) -> bool { - matches!(self, Count::Implied(_)) - } - - pub fn param(self) -> Option<FormatParam<'tcx>> { - match self { - Count::Param(param) => Some(param), - _ => None, - } - } - - pub fn span(self) -> Option<Span> { - match self { - Count::Is(_, span) => Some(span), - Count::Param(param) => Some(param.span), - Count::Implied(span) => span, - } - } -} - -/// Specification for the formatting of an argument in the format string. See -/// <https://doc.rust-lang.org/std/fmt/index.html#formatting-parameters> for the precise meanings. -#[derive(Debug)] -pub struct FormatSpec<'tcx> { - /// Optionally specified character to fill alignment with. - pub fill: Option<char>, - /// Optionally specified alignment. - pub align: Alignment, - /// Whether all flag options are set to default (no flags specified). - pub no_flags: bool, - /// Represents either the maximum width or the integer precision. - pub precision: Count<'tcx>, - /// The minimum width, will be padded according to `width`/`align` - pub width: Count<'tcx>, - /// The formatting trait used by the argument, e.g. `sym::Display` for `{}`, `sym::Debug` for - /// `{:?}`. - pub r#trait: Symbol, - pub trait_span: Option<Span>, -} - -impl<'tcx> FormatSpec<'tcx> { - fn new(spec: rpf::FormatSpec<'_>, positions: ParamPosition, values: &FormatArgsValues<'tcx>) -> Option<Self> { - Some(Self { - fill: spec.fill, - align: spec.align, - no_flags: spec.sign.is_none() && !spec.alternate && !spec.zero_pad && spec.debug_hex.is_none(), - precision: Count::new( - FormatParamUsage::Precision, - spec.precision, - positions.precision, - spec.precision_span, - values, - )?, - width: Count::new( - FormatParamUsage::Width, - spec.width, - positions.width, - spec.width_span, - values, - )?, - r#trait: match spec.ty { - "" => sym::Display, - "?" => sym::Debug, - "o" => sym!(Octal), - "x" => sym!(LowerHex), - "X" => sym!(UpperHex), - "p" => sym::Pointer, - "b" => sym!(Binary), - "e" => sym!(LowerExp), - "E" => sym!(UpperExp), - _ => return None, - }, - trait_span: spec - .ty_span - .map(|span| span_from_inner(values.format_string_span, span)), - }) - } - - /// Returns true if this format spec is unchanged from the default. e.g. returns true for `{}`, - /// `{foo}` and `{2}`, but false for `{:?}`, `{foo:5}` and `{3:.5}` - pub fn is_default(&self) -> bool { - self.r#trait == sym::Display && self.is_default_for_trait() - } - - /// Has no other formatting specifiers than setting the format trait. returns true for `{}`, - /// `{foo}`, `{:?}`, but false for `{foo:5}`, `{3:.5?}` - pub fn is_default_for_trait(&self) -> bool { - self.width.is_implied() && self.precision.is_implied() && self.align == Alignment::AlignUnknown && self.no_flags - } -} - -/// A format argument, such as `{}`, `{foo:?}`. -#[derive(Debug)] -pub struct FormatArg<'tcx> { - /// The parameter the argument refers to. - pub param: FormatParam<'tcx>, - /// How to format `param`. - pub format: FormatSpec<'tcx>, - /// span of the whole argument, `{..}`. - pub span: Span, -} - -impl<'tcx> FormatArg<'tcx> { - /// Span of the `:` and format specifiers - /// - /// ```ignore - /// format!("{:.}"), format!("{foo:.}") - /// ^^ ^^ - /// ``` - pub fn format_span(&self) -> Span { - let base = self.span.data(); - - // `base.hi` is `{...}|`, subtract 1 byte (the length of '}') so that it points before the closing - // brace `{...|}` - Span::new(self.param.span.hi(), base.hi - BytePos(1), base.ctxt, base.parent) - } -} - -/// A parsed `format_args!` expansion. -#[derive(Debug)] -pub struct FormatArgsExpn<'tcx> { - /// The format string literal. - pub format_string: FormatString, - /// The format arguments, such as `{:?}`. - pub args: Vec<FormatArg<'tcx>>, - /// Has an added newline due to `println!()`/`writeln!()`/etc. The last format string part will - /// include this added newline. - pub newline: bool, - /// Spans of the commas between the format string and explicit values, excluding any trailing - /// comma - /// - /// ```ignore - /// format!("..", 1, 2, 3,) - /// // ^ ^ ^ - /// ``` - comma_spans: Vec<Span>, - /// Explicit values passed after the format string, ignoring implicit captures. `[1, z + 2]` for - /// `format!("{x} {} {y}", 1, z + 2)`. - explicit_values: Vec<&'tcx Expr<'tcx>>, -} - -impl<'tcx> FormatArgsExpn<'tcx> { - /// Gets the spans of the commas inbetween the format string and explicit args, not including - /// any trailing comma - /// - /// ```ignore - /// format!("{} {}", a, b) - /// // ^ ^ - /// ``` - /// - /// Ensures that the format string and values aren't coming from a proc macro that sets the - /// output span to that of its input - fn comma_spans(cx: &LateContext<'_>, explicit_values: &[&Expr<'_>], fmt_span: Span) -> Option<Vec<Span>> { - // `format!("{} {} {c}", "one", "two", c = "three")` - // ^^^^^ ^^^^^ ^^^^^^^ - let value_spans = explicit_values - .iter() - .map(|val| hygiene::walk_chain(val.span, fmt_span.ctxt())); - - // `format!("{} {} {c}", "one", "two", c = "three")` - // ^^ ^^ ^^^^^^ - let between_spans = once(fmt_span) - .chain(value_spans) - .tuple_windows() - .map(|(start, end)| start.between(end)); - - let mut comma_spans = Vec::new(); - for between_span in between_spans { - let mut offset = 0; - let mut seen_comma = false; - - for token in tokenize(&snippet_opt(cx, between_span)?) { - match token.kind { - TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace => {}, - TokenKind::Comma if !seen_comma => { - seen_comma = true; - - let base = between_span.data(); - comma_spans.push(Span::new( - base.lo + BytePos(offset), - base.lo + BytePos(offset + 1), - base.ctxt, - base.parent, - )); - }, - // named arguments, `start_val, name = end_val` - // ^^^^^^^^^ between_span - TokenKind::Ident | TokenKind::Eq if seen_comma => {}, - // An unexpected token usually indicates the format string or a value came from a proc macro output - // that sets the span of its output to an input, e.g. `println!(some_proc_macro!("input"), ..)` that - // emits a string literal with the span set to that of `"input"` - _ => return None, - } - offset += token.len; - } - - if !seen_comma { - return None; - } - } - - Some(comma_spans) - } - - pub fn parse(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<Self> { - let macro_name = macro_backtrace(expr.span) - .map(|macro_call| cx.tcx.item_name(macro_call.def_id)) - .find(|&name| matches!(name, sym::const_format_args | sym::format_args | sym::format_args_nl))?; - let newline = macro_name == sym::format_args_nl; - - // ::core::fmt::Arguments::new_v1(pieces, args) - // ::core::fmt::Arguments::new_v1_formatted(pieces, args, fmt, _unsafe_arg) - if let ExprKind::Call(callee, [pieces, args, rest @ ..]) = expr.kind - && let ExprKind::Path(QPath::TypeRelative(ty, seg)) = callee.kind - && let TyKind::Path(QPath::LangItem(LangItem::FormatArguments, _, _)) = ty.kind - && matches!(seg.ident.as_str(), "new_v1" | "new_v1_formatted") - { - let format_string = FormatString::new(cx, pieces)?; - - let mut parser = rpf::Parser::new( - &format_string.unescaped, - format_string.style, - Some(format_string.snippet.clone()), - // `format_string.unescaped` does not contain the appended newline - false, - rpf::ParseMode::Format, - ); - - let parsed_args = parser - .by_ref() - .filter_map(|piece| match piece { - rpf::Piece::NextArgument(a) => Some(a), - rpf::Piece::String(_) => None, - }) - .collect_vec(); - if !parser.errors.is_empty() { - return None; - } - - let positions = if let Some(fmt_arg) = rest.first() { - // If the argument contains format specs, `new_v1_formatted(_, _, fmt, _)`, parse - // them. - - Either::Left(parse_rt_fmt(fmt_arg)?) - } else { - // If no format specs are given, the positions are in the given order and there are - // no `precision`/`width`s to consider. - - Either::Right((0..).map(|n| ParamPosition { - value: n, - width: None, - precision: None, - })) - }; - - let values = FormatArgsValues::new(args, format_string.span.data()); - - let args = izip!(positions, parsed_args, parser.arg_places) - .map(|(position, parsed_arg, arg_span)| { - Some(FormatArg { - param: FormatParam::new( - match parsed_arg.position { - rpf::Position::ArgumentImplicitlyIs(_) => FormatParamKind::Implicit, - rpf::Position::ArgumentIs(_) => FormatParamKind::Numbered, - // NamedInline is handled by `FormatParam::new()` - rpf::Position::ArgumentNamed(name) => FormatParamKind::Named(Symbol::intern(name)), - }, - FormatParamUsage::Argument, - position.value, - parsed_arg.position_span, - &values, - )?, - format: FormatSpec::new(parsed_arg.format, position, &values)?, - span: span_from_inner(values.format_string_span, arg_span), - }) - }) - .collect::<Option<Vec<_>>>()?; - - let mut explicit_values = values.value_args; - // remove values generated for implicitly captured vars - let len = explicit_values - .iter() - .take_while(|val| !format_string.span.contains(val.span)) - .count(); - explicit_values.truncate(len); - - let comma_spans = Self::comma_spans(cx, &explicit_values, format_string.span)?; - - Some(Self { - format_string, - args, - newline, - comma_spans, - explicit_values, - }) - } else { - None - } - } - - pub fn find_nested(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, expn_id: ExpnId) -> Option<Self> { - for_each_expr(expr, |e| { - let e_ctxt = e.span.ctxt(); - if e_ctxt == expr.span.ctxt() { - ControlFlow::Continue(Descend::Yes) - } else if e_ctxt.outer_expn().is_descendant_of(expn_id) { - if let Some(args) = FormatArgsExpn::parse(cx, e) { - ControlFlow::Break(args) - } else { - ControlFlow::Continue(Descend::No) - } - } else { - ControlFlow::Continue(Descend::No) - } - }) - } - - /// Source callsite span of all inputs - pub fn inputs_span(&self) -> Span { - match *self.explicit_values { - [] => self.format_string.span, - [.., last] => self - .format_string - .span - .to(hygiene::walk_chain(last.span, self.format_string.span.ctxt())), - } - } - - /// Get the span of a value expanded to the previous comma, e.g. for the value `10` - /// - /// ```ignore - /// format("{}.{}", 10, 11) - /// // ^^^^ - /// ``` - pub fn value_with_prev_comma_span(&self, value_id: HirId) -> Option<Span> { - for (comma_span, value) in zip(&self.comma_spans, &self.explicit_values) { - if value.hir_id == value_id { - return Some(comma_span.to(hygiene::walk_chain(value.span, comma_span.ctxt()))); - } - } - - None - } - - /// Iterator of all format params, both values and those referenced by `width`/`precision`s. - pub fn params(&'tcx self) -> impl Iterator<Item = FormatParam<'tcx>> { - self.args - .iter() - .flat_map(|arg| [Some(arg.param), arg.format.precision.param(), arg.format.width.param()]) - .flatten() - } -} - /// A node with a `HirId` and a `Span` pub trait HirNode { fn hir_id(&self) -> HirId; |