746 lines
26 KiB
Rust
746 lines
26 KiB
Rust
//! Contains utility functions to generate suggestions.
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#![deny(clippy::missing_docs_in_private_items)]
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use crate::higher;
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use crate::source::{snippet, snippet_opt, snippet_with_context, snippet_with_macro_callsite};
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use rustc_ast::util::parser::AssocOp;
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use rustc_ast::{ast, token};
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use rustc_ast_pretty::pprust::token_kind_to_string;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_lint::{EarlyContext, LateContext, LintContext};
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use rustc_span::source_map::{CharPos, Span};
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use rustc_span::{BytePos, Pos, SyntaxContext};
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use std::borrow::Cow;
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use std::convert::TryInto;
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use std::fmt::Display;
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use std::ops::{Add, Neg, Not, Sub};
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/// A helper type to build suggestion correctly handling parenthesis.
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#[derive(Clone, PartialEq)]
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pub enum Sugg<'a> {
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/// An expression that never needs parenthesis such as `1337` or `[0; 42]`.
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NonParen(Cow<'a, str>),
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/// An expression that does not fit in other variants.
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MaybeParen(Cow<'a, str>),
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/// A binary operator expression, including `as`-casts and explicit type
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/// coercion.
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BinOp(AssocOp, Cow<'a, str>),
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}
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/// Literal constant `0`, for convenience.
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pub const ZERO: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("0"));
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/// Literal constant `1`, for convenience.
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pub const ONE: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("1"));
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/// a constant represents an empty string, for convenience.
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pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed(""));
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impl Display for Sugg<'_> {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
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match *self {
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Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) | Sugg::BinOp(_, ref s) => s.fmt(f),
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}
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}
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}
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#[allow(clippy::wrong_self_convention)] // ok, because of the function `as_ty` method
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impl<'a> Sugg<'a> {
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/// Prepare a suggestion from an expression.
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pub fn hir_opt(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Self> {
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snippet_opt(cx, expr.span).map(|snippet| {
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let snippet = Cow::Owned(snippet);
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Self::hir_from_snippet(expr, snippet)
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})
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}
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/// Convenience function around `hir_opt` for suggestions with a default
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/// text.
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pub fn hir(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self {
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Self::hir_opt(cx, expr).unwrap_or(Sugg::NonParen(Cow::Borrowed(default)))
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}
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/// Same as `hir`, but it adapts the applicability level by following rules:
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///
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/// - Applicability level `Unspecified` will never be changed.
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/// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
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/// - If the default value is used and the applicability level is `MachineApplicable`, change it
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/// to
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/// `HasPlaceholders`
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pub fn hir_with_applicability(
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cx: &LateContext<'_>,
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expr: &hir::Expr<'_>,
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default: &'a str,
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applicability: &mut Applicability,
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) -> Self {
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if *applicability != Applicability::Unspecified && expr.span.from_expansion() {
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*applicability = Applicability::MaybeIncorrect;
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}
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Self::hir_opt(cx, expr).unwrap_or_else(|| {
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if *applicability == Applicability::MachineApplicable {
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*applicability = Applicability::HasPlaceholders;
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}
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Sugg::NonParen(Cow::Borrowed(default))
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})
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}
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/// Same as `hir`, but will use the pre expansion span if the `expr` was in a macro.
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pub fn hir_with_macro_callsite(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self {
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let snippet = snippet_with_macro_callsite(cx, expr.span, default);
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Self::hir_from_snippet(expr, snippet)
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}
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/// Same as `hir`, but first walks the span up to the given context. This will result in the
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/// macro call, rather then the expansion, if the span is from a child context. If the span is
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/// not from a child context, it will be used directly instead.
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///
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/// e.g. Given the expression `&vec![]`, getting a snippet from the span for `vec![]` as a HIR
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/// node would result in `box []`. If given the context of the address of expression, this
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/// function will correctly get a snippet of `vec![]`.
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pub fn hir_with_context(
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cx: &LateContext<'_>,
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expr: &hir::Expr<'_>,
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ctxt: SyntaxContext,
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default: &'a str,
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applicability: &mut Applicability,
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) -> Self {
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let (snippet, in_macro) = snippet_with_context(cx, expr.span, ctxt, default, applicability);
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if in_macro {
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Sugg::NonParen(snippet)
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} else {
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Self::hir_from_snippet(expr, snippet)
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}
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}
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/// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*`
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/// function variants of `Sugg`, since these use different snippet functions.
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fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self {
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if let Some(range) = higher::range(expr) {
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let op = match range.limits {
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ast::RangeLimits::HalfOpen => AssocOp::DotDot,
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ast::RangeLimits::Closed => AssocOp::DotDotEq,
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};
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return Sugg::BinOp(op, snippet);
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}
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match expr.kind {
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hir::ExprKind::AddrOf(..)
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| hir::ExprKind::Box(..)
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| hir::ExprKind::If(..)
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| hir::ExprKind::Closure(..)
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| hir::ExprKind::Unary(..)
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| hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
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hir::ExprKind::Continue(..)
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| hir::ExprKind::Yield(..)
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| hir::ExprKind::Array(..)
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| hir::ExprKind::Block(..)
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| hir::ExprKind::Break(..)
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| hir::ExprKind::Call(..)
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| hir::ExprKind::Field(..)
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| hir::ExprKind::Index(..)
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| hir::ExprKind::InlineAsm(..)
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| hir::ExprKind::LlvmInlineAsm(..)
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| hir::ExprKind::ConstBlock(..)
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| hir::ExprKind::Lit(..)
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| hir::ExprKind::Loop(..)
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| hir::ExprKind::MethodCall(..)
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| hir::ExprKind::Path(..)
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| hir::ExprKind::Repeat(..)
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| hir::ExprKind::Ret(..)
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| hir::ExprKind::Struct(..)
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| hir::ExprKind::Tup(..)
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| hir::ExprKind::DropTemps(_)
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| hir::ExprKind::Err => Sugg::NonParen(snippet),
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hir::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
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hir::ExprKind::AssignOp(op, ..) => Sugg::BinOp(hirbinop2assignop(op), snippet),
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hir::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(higher::binop(op.node)), snippet),
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hir::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
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hir::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
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}
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}
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/// Prepare a suggestion from an expression.
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pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
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use rustc_ast::ast::RangeLimits;
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let snippet = if expr.span.from_expansion() {
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snippet_with_macro_callsite(cx, expr.span, default)
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} else {
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snippet(cx, expr.span, default)
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};
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match expr.kind {
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ast::ExprKind::AddrOf(..)
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| ast::ExprKind::Box(..)
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| ast::ExprKind::Closure(..)
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| ast::ExprKind::If(..)
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| ast::ExprKind::Let(..)
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| ast::ExprKind::Unary(..)
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| ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
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ast::ExprKind::Async(..)
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| ast::ExprKind::Block(..)
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| ast::ExprKind::Break(..)
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| ast::ExprKind::Call(..)
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| ast::ExprKind::Continue(..)
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| ast::ExprKind::Yield(..)
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| ast::ExprKind::Field(..)
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| ast::ExprKind::ForLoop(..)
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| ast::ExprKind::Index(..)
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| ast::ExprKind::InlineAsm(..)
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| ast::ExprKind::LlvmInlineAsm(..)
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| ast::ExprKind::ConstBlock(..)
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| ast::ExprKind::Lit(..)
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| ast::ExprKind::Loop(..)
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| ast::ExprKind::MacCall(..)
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| ast::ExprKind::MethodCall(..)
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| ast::ExprKind::Paren(..)
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| ast::ExprKind::Underscore
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| ast::ExprKind::Path(..)
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| ast::ExprKind::Repeat(..)
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| ast::ExprKind::Ret(..)
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| ast::ExprKind::Struct(..)
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| ast::ExprKind::Try(..)
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| ast::ExprKind::TryBlock(..)
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| ast::ExprKind::Tup(..)
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| ast::ExprKind::Array(..)
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| ast::ExprKind::While(..)
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| ast::ExprKind::Await(..)
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| ast::ExprKind::Err => Sugg::NonParen(snippet),
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ast::ExprKind::Range(.., RangeLimits::HalfOpen) => Sugg::BinOp(AssocOp::DotDot, snippet),
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ast::ExprKind::Range(.., RangeLimits::Closed) => Sugg::BinOp(AssocOp::DotDotEq, snippet),
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ast::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
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ast::ExprKind::AssignOp(op, ..) => Sugg::BinOp(astbinop2assignop(op), snippet),
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ast::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node), snippet),
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ast::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
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ast::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
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}
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}
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/// Convenience method to create the `<lhs> && <rhs>` suggestion.
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pub fn and(self, rhs: &Self) -> Sugg<'static> {
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make_binop(ast::BinOpKind::And, &self, rhs)
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}
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/// Convenience method to create the `<lhs> & <rhs>` suggestion.
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pub fn bit_and(self, rhs: &Self) -> Sugg<'static> {
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make_binop(ast::BinOpKind::BitAnd, &self, rhs)
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}
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/// Convenience method to create the `<lhs> as <rhs>` suggestion.
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pub fn as_ty<R: Display>(self, rhs: R) -> Sugg<'static> {
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make_assoc(AssocOp::As, &self, &Sugg::NonParen(rhs.to_string().into()))
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}
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/// Convenience method to create the `&<expr>` suggestion.
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pub fn addr(self) -> Sugg<'static> {
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make_unop("&", self)
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}
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/// Convenience method to create the `&mut <expr>` suggestion.
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pub fn mut_addr(self) -> Sugg<'static> {
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make_unop("&mut ", self)
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}
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/// Convenience method to create the `*<expr>` suggestion.
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pub fn deref(self) -> Sugg<'static> {
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make_unop("*", self)
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}
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/// Convenience method to create the `&*<expr>` suggestion. Currently this
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/// is needed because `sugg.deref().addr()` produces an unnecessary set of
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/// parentheses around the deref.
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pub fn addr_deref(self) -> Sugg<'static> {
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make_unop("&*", self)
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}
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/// Convenience method to create the `&mut *<expr>` suggestion. Currently
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/// this is needed because `sugg.deref().mut_addr()` produces an unnecessary
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/// set of parentheses around the deref.
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pub fn mut_addr_deref(self) -> Sugg<'static> {
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make_unop("&mut *", self)
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}
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/// Convenience method to transform suggestion into a return call
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pub fn make_return(self) -> Sugg<'static> {
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Sugg::NonParen(Cow::Owned(format!("return {}", self)))
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}
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/// Convenience method to transform suggestion into a block
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/// where the suggestion is a trailing expression
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pub fn blockify(self) -> Sugg<'static> {
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Sugg::NonParen(Cow::Owned(format!("{{ {} }}", self)))
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}
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/// Convenience method to create the `<lhs>..<rhs>` or `<lhs>...<rhs>`
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/// suggestion.
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#[allow(dead_code)]
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pub fn range(self, end: &Self, limit: ast::RangeLimits) -> Sugg<'static> {
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match limit {
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ast::RangeLimits::HalfOpen => make_assoc(AssocOp::DotDot, &self, end),
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ast::RangeLimits::Closed => make_assoc(AssocOp::DotDotEq, &self, end),
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}
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}
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/// Adds parenthesis to any expression that might need them. Suitable to the
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/// `self` argument of a method call
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/// (e.g., to build `bar.foo()` or `(1 + 2).foo()`).
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pub fn maybe_par(self) -> Self {
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match self {
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Sugg::NonParen(..) => self,
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// `(x)` and `(x).y()` both don't need additional parens.
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Sugg::MaybeParen(sugg) => {
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if has_enclosing_paren(&sugg) {
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Sugg::MaybeParen(sugg)
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} else {
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Sugg::NonParen(format!("({})", sugg).into())
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}
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},
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Sugg::BinOp(_, sugg) => {
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if has_enclosing_paren(&sugg) {
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Sugg::NonParen(sugg)
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} else {
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Sugg::NonParen(format!("({})", sugg).into())
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}
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},
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}
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}
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}
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/// Return `true` if `sugg` is enclosed in parenthesis.
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fn has_enclosing_paren(sugg: impl AsRef<str>) -> bool {
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let mut chars = sugg.as_ref().chars();
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if let Some('(') = chars.next() {
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let mut depth = 1;
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for c in &mut chars {
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if c == '(' {
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depth += 1;
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} else if c == ')' {
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depth -= 1;
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}
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if depth == 0 {
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break;
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}
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}
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chars.next().is_none()
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} else {
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false
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}
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}
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// Copied from the rust standart library, and then edited
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macro_rules! forward_binop_impls_to_ref {
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(impl $imp:ident, $method:ident for $t:ty, type Output = $o:ty) => {
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impl $imp<$t> for &$t {
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type Output = $o;
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fn $method(self, other: $t) -> $o {
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$imp::$method(self, &other)
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}
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}
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impl $imp<&$t> for $t {
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type Output = $o;
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fn $method(self, other: &$t) -> $o {
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$imp::$method(&self, other)
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}
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}
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impl $imp for $t {
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type Output = $o;
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fn $method(self, other: $t) -> $o {
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$imp::$method(&self, &other)
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}
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}
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};
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}
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impl Add for &Sugg<'_> {
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type Output = Sugg<'static>;
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fn add(self, rhs: &Sugg<'_>) -> Sugg<'static> {
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make_binop(ast::BinOpKind::Add, self, rhs)
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}
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}
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impl Sub for &Sugg<'_> {
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type Output = Sugg<'static>;
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fn sub(self, rhs: &Sugg<'_>) -> Sugg<'static> {
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make_binop(ast::BinOpKind::Sub, self, rhs)
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}
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}
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forward_binop_impls_to_ref!(impl Add, add for Sugg<'_>, type Output = Sugg<'static>);
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forward_binop_impls_to_ref!(impl Sub, sub for Sugg<'_>, type Output = Sugg<'static>);
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impl Neg for Sugg<'_> {
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type Output = Sugg<'static>;
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fn neg(self) -> Sugg<'static> {
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make_unop("-", self)
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}
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}
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impl Not for Sugg<'_> {
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type Output = Sugg<'static>;
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fn not(self) -> Sugg<'static> {
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make_unop("!", self)
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}
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}
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/// Helper type to display either `foo` or `(foo)`.
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struct ParenHelper<T> {
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/// `true` if parentheses are needed.
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paren: bool,
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/// The main thing to display.
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wrapped: T,
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}
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impl<T> ParenHelper<T> {
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/// Builds a `ParenHelper`.
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fn new(paren: bool, wrapped: T) -> Self {
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Self { paren, wrapped }
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}
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}
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impl<T: Display> Display for ParenHelper<T> {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
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if self.paren {
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write!(f, "({})", self.wrapped)
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} else {
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self.wrapped.fmt(f)
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}
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}
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}
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/// Builds the string for `<op><expr>` adding parenthesis when necessary.
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///
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/// For convenience, the operator is taken as a string because all unary
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/// operators have the same
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/// precedence.
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pub fn make_unop(op: &str, expr: Sugg<'_>) -> Sugg<'static> {
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Sugg::MaybeParen(format!("{}{}", op, expr.maybe_par()).into())
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}
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/// Builds the string for `<lhs> <op> <rhs>` adding parenthesis when necessary.
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///
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/// Precedence of shift operator relative to other arithmetic operation is
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/// often confusing so
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/// parenthesis will always be added for a mix of these.
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pub fn make_assoc(op: AssocOp, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> {
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/// Returns `true` if the operator is a shift operator `<<` or `>>`.
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fn is_shift(op: AssocOp) -> bool {
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matches!(op, AssocOp::ShiftLeft | AssocOp::ShiftRight)
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}
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/// Returns `true` if the operator is a arithmetic operator
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/// (i.e., `+`, `-`, `*`, `/`, `%`).
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fn is_arith(op: AssocOp) -> bool {
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matches!(
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op,
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AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide | AssocOp::Modulus
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)
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}
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/// Returns `true` if the operator `op` needs parenthesis with the operator
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/// `other` in the direction `dir`.
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fn needs_paren(op: AssocOp, other: AssocOp, dir: Associativity) -> bool {
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other.precedence() < op.precedence()
|
|
|| (other.precedence() == op.precedence()
|
|
&& ((op != other && associativity(op) != dir)
|
|
|| (op == other && associativity(op) != Associativity::Both)))
|
|
|| is_shift(op) && is_arith(other)
|
|
|| is_shift(other) && is_arith(op)
|
|
}
|
|
|
|
let lhs_paren = if let Sugg::BinOp(lop, _) = *lhs {
|
|
needs_paren(op, lop, Associativity::Left)
|
|
} else {
|
|
false
|
|
};
|
|
|
|
let rhs_paren = if let Sugg::BinOp(rop, _) = *rhs {
|
|
needs_paren(op, rop, Associativity::Right)
|
|
} else {
|
|
false
|
|
};
|
|
|
|
let lhs = ParenHelper::new(lhs_paren, lhs);
|
|
let rhs = ParenHelper::new(rhs_paren, rhs);
|
|
let sugg = match op {
|
|
AssocOp::Add
|
|
| AssocOp::BitAnd
|
|
| AssocOp::BitOr
|
|
| AssocOp::BitXor
|
|
| AssocOp::Divide
|
|
| AssocOp::Equal
|
|
| AssocOp::Greater
|
|
| AssocOp::GreaterEqual
|
|
| AssocOp::LAnd
|
|
| AssocOp::LOr
|
|
| AssocOp::Less
|
|
| AssocOp::LessEqual
|
|
| AssocOp::Modulus
|
|
| AssocOp::Multiply
|
|
| AssocOp::NotEqual
|
|
| AssocOp::ShiftLeft
|
|
| AssocOp::ShiftRight
|
|
| AssocOp::Subtract => format!(
|
|
"{} {} {}",
|
|
lhs,
|
|
op.to_ast_binop().expect("Those are AST ops").to_string(),
|
|
rhs
|
|
),
|
|
AssocOp::Assign => format!("{} = {}", lhs, rhs),
|
|
AssocOp::AssignOp(op) => format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs),
|
|
AssocOp::As => format!("{} as {}", lhs, rhs),
|
|
AssocOp::DotDot => format!("{}..{}", lhs, rhs),
|
|
AssocOp::DotDotEq => format!("{}..={}", lhs, rhs),
|
|
AssocOp::Colon => format!("{}: {}", lhs, rhs),
|
|
};
|
|
|
|
Sugg::BinOp(op, sugg.into())
|
|
}
|
|
|
|
/// Convenience wrapper around `make_assoc` and `AssocOp::from_ast_binop`.
|
|
pub fn make_binop(op: ast::BinOpKind, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> {
|
|
make_assoc(AssocOp::from_ast_binop(op), lhs, rhs)
|
|
}
|
|
|
|
#[derive(PartialEq, Eq, Clone, Copy)]
|
|
/// Operator associativity.
|
|
enum Associativity {
|
|
/// The operator is both left-associative and right-associative.
|
|
Both,
|
|
/// The operator is left-associative.
|
|
Left,
|
|
/// The operator is not associative.
|
|
None,
|
|
/// The operator is right-associative.
|
|
Right,
|
|
}
|
|
|
|
/// Returns the associativity/fixity of an operator. The difference with
|
|
/// `AssocOp::fixity` is that an operator can be both left and right associative
|
|
/// (such as `+`: `a + b + c == (a + b) + c == a + (b + c)`.
|
|
///
|
|
/// Chained `as` and explicit `:` type coercion never need inner parenthesis so
|
|
/// they are considered
|
|
/// associative.
|
|
#[must_use]
|
|
fn associativity(op: AssocOp) -> Associativity {
|
|
use rustc_ast::util::parser::AssocOp::{
|
|
Add, As, Assign, AssignOp, BitAnd, BitOr, BitXor, Colon, Divide, DotDot, DotDotEq, Equal, Greater,
|
|
GreaterEqual, LAnd, LOr, Less, LessEqual, Modulus, Multiply, NotEqual, ShiftLeft, ShiftRight, Subtract,
|
|
};
|
|
|
|
match op {
|
|
Assign | AssignOp(_) => Associativity::Right,
|
|
Add | BitAnd | BitOr | BitXor | LAnd | LOr | Multiply | As | Colon => Associativity::Both,
|
|
Divide | Equal | Greater | GreaterEqual | Less | LessEqual | Modulus | NotEqual | ShiftLeft | ShiftRight
|
|
| Subtract => Associativity::Left,
|
|
DotDot | DotDotEq => Associativity::None,
|
|
}
|
|
}
|
|
|
|
/// Converts a `hir::BinOp` to the corresponding assigning binary operator.
|
|
fn hirbinop2assignop(op: hir::BinOp) -> AssocOp {
|
|
use rustc_ast::token::BinOpToken::{And, Caret, Minus, Or, Percent, Plus, Shl, Shr, Slash, Star};
|
|
|
|
AssocOp::AssignOp(match op.node {
|
|
hir::BinOpKind::Add => Plus,
|
|
hir::BinOpKind::BitAnd => And,
|
|
hir::BinOpKind::BitOr => Or,
|
|
hir::BinOpKind::BitXor => Caret,
|
|
hir::BinOpKind::Div => Slash,
|
|
hir::BinOpKind::Mul => Star,
|
|
hir::BinOpKind::Rem => Percent,
|
|
hir::BinOpKind::Shl => Shl,
|
|
hir::BinOpKind::Shr => Shr,
|
|
hir::BinOpKind::Sub => Minus,
|
|
|
|
hir::BinOpKind::And
|
|
| hir::BinOpKind::Eq
|
|
| hir::BinOpKind::Ge
|
|
| hir::BinOpKind::Gt
|
|
| hir::BinOpKind::Le
|
|
| hir::BinOpKind::Lt
|
|
| hir::BinOpKind::Ne
|
|
| hir::BinOpKind::Or => panic!("This operator does not exist"),
|
|
})
|
|
}
|
|
|
|
/// Converts an `ast::BinOp` to the corresponding assigning binary operator.
|
|
fn astbinop2assignop(op: ast::BinOp) -> AssocOp {
|
|
use rustc_ast::ast::BinOpKind::{
|
|
Add, And, BitAnd, BitOr, BitXor, Div, Eq, Ge, Gt, Le, Lt, Mul, Ne, Or, Rem, Shl, Shr, Sub,
|
|
};
|
|
use rustc_ast::token::BinOpToken;
|
|
|
|
AssocOp::AssignOp(match op.node {
|
|
Add => BinOpToken::Plus,
|
|
BitAnd => BinOpToken::And,
|
|
BitOr => BinOpToken::Or,
|
|
BitXor => BinOpToken::Caret,
|
|
Div => BinOpToken::Slash,
|
|
Mul => BinOpToken::Star,
|
|
Rem => BinOpToken::Percent,
|
|
Shl => BinOpToken::Shl,
|
|
Shr => BinOpToken::Shr,
|
|
Sub => BinOpToken::Minus,
|
|
And | Eq | Ge | Gt | Le | Lt | Ne | Or => panic!("This operator does not exist"),
|
|
})
|
|
}
|
|
|
|
/// Returns the indentation before `span` if there are nothing but `[ \t]`
|
|
/// before it on its line.
|
|
fn indentation<T: LintContext>(cx: &T, span: Span) -> Option<String> {
|
|
let lo = cx.sess().source_map().lookup_char_pos(span.lo());
|
|
lo.file
|
|
.get_line(lo.line - 1 /* line numbers in `Loc` are 1-based */)
|
|
.and_then(|line| {
|
|
if let Some((pos, _)) = line.char_indices().find(|&(_, c)| c != ' ' && c != '\t') {
|
|
// We can mix char and byte positions here because we only consider `[ \t]`.
|
|
if lo.col == CharPos(pos) {
|
|
Some(line[..pos].into())
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
}
|
|
|
|
/// Convenience extension trait for `DiagnosticBuilder`.
|
|
pub trait DiagnosticBuilderExt<T: LintContext> {
|
|
/// Suggests to add an attribute to an item.
|
|
///
|
|
/// Correctly handles indentation of the attribute and item.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust,ignore
|
|
/// diag.suggest_item_with_attr(cx, item, "#[derive(Default)]");
|
|
/// ```
|
|
fn suggest_item_with_attr<D: Display + ?Sized>(
|
|
&mut self,
|
|
cx: &T,
|
|
item: Span,
|
|
msg: &str,
|
|
attr: &D,
|
|
applicability: Applicability,
|
|
);
|
|
|
|
/// Suggest to add an item before another.
|
|
///
|
|
/// The item should not be indented (except for inner indentation).
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust,ignore
|
|
/// diag.suggest_prepend_item(cx, item,
|
|
/// "fn foo() {
|
|
/// bar();
|
|
/// }");
|
|
/// ```
|
|
fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability);
|
|
|
|
/// Suggest to completely remove an item.
|
|
///
|
|
/// This will remove an item and all following whitespace until the next non-whitespace
|
|
/// character. This should work correctly if item is on the same indentation level as the
|
|
/// following item.
|
|
///
|
|
/// # Example
|
|
///
|
|
/// ```rust,ignore
|
|
/// diag.suggest_remove_item(cx, item, "remove this")
|
|
/// ```
|
|
fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability);
|
|
}
|
|
|
|
impl<T: LintContext> DiagnosticBuilderExt<T> for rustc_errors::DiagnosticBuilder<'_> {
|
|
fn suggest_item_with_attr<D: Display + ?Sized>(
|
|
&mut self,
|
|
cx: &T,
|
|
item: Span,
|
|
msg: &str,
|
|
attr: &D,
|
|
applicability: Applicability,
|
|
) {
|
|
if let Some(indent) = indentation(cx, item) {
|
|
let span = item.with_hi(item.lo());
|
|
|
|
self.span_suggestion(span, msg, format!("{}\n{}", attr, indent), applicability);
|
|
}
|
|
}
|
|
|
|
fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability) {
|
|
if let Some(indent) = indentation(cx, item) {
|
|
let span = item.with_hi(item.lo());
|
|
|
|
let mut first = true;
|
|
let new_item = new_item
|
|
.lines()
|
|
.map(|l| {
|
|
if first {
|
|
first = false;
|
|
format!("{}\n", l)
|
|
} else {
|
|
format!("{}{}\n", indent, l)
|
|
}
|
|
})
|
|
.collect::<String>();
|
|
|
|
self.span_suggestion(span, msg, format!("{}\n{}", new_item, indent), applicability);
|
|
}
|
|
}
|
|
|
|
fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability) {
|
|
let mut remove_span = item;
|
|
let hi = cx.sess().source_map().next_point(remove_span).hi();
|
|
let fmpos = cx.sess().source_map().lookup_byte_offset(hi);
|
|
|
|
if let Some(ref src) = fmpos.sf.src {
|
|
let non_whitespace_offset = src[fmpos.pos.to_usize()..].find(|c| c != ' ' && c != '\t' && c != '\n');
|
|
|
|
if let Some(non_whitespace_offset) = non_whitespace_offset {
|
|
remove_span = remove_span
|
|
.with_hi(remove_span.hi() + BytePos(non_whitespace_offset.try_into().expect("offset too large")));
|
|
}
|
|
}
|
|
|
|
self.span_suggestion(remove_span, msg, String::new(), applicability);
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use super::Sugg;
|
|
|
|
use rustc_ast::util::parser::AssocOp;
|
|
use std::borrow::Cow;
|
|
|
|
const SUGGESTION: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("function_call()"));
|
|
|
|
#[test]
|
|
fn make_return_transform_sugg_into_a_return_call() {
|
|
assert_eq!("return function_call()", SUGGESTION.make_return().to_string());
|
|
}
|
|
|
|
#[test]
|
|
fn blockify_transforms_sugg_into_a_block() {
|
|
assert_eq!("{ function_call() }", SUGGESTION.blockify().to_string());
|
|
}
|
|
|
|
#[test]
|
|
fn binop_maybe_par() {
|
|
let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into());
|
|
assert_eq!("(1 + 1)", sugg.maybe_par().to_string());
|
|
|
|
let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1) + (1 + 1)".into());
|
|
assert_eq!("((1 + 1) + (1 + 1))", sugg.maybe_par().to_string());
|
|
}
|
|
}
|