-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);
+ },
+ _ => (),