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Auto merge of #8117 - hotate29:issue7320, r=camsteffen

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update: ```Sugg::not()``` replacing the comparison operator. #7320

fixes #7320

changelog: ```needless_bool```: Changed to make a smart suggestion.
This commit is contained in:
bors 2021-12-28 22:15:53 +00:00
commit c1cd64b9c6
11 changed files with 307 additions and 128 deletions
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251
clippy_utils/src/sugg.rs
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@ -1,9 +1,7 @@
//! Contains utility functions to generate suggestions.
#![deny(clippy::missing_docs_in_private_items)]
use crate::source::{
snippet, snippet_opt, snippet_with_applicability, snippet_with_context, snippet_with_macro_callsite,
};
use crate::source::{snippet, snippet_opt, snippet_with_applicability, snippet_with_macro_callsite};
use crate::{get_parent_expr_for_hir, higher};
use rustc_ast::util::parser::AssocOp;
use rustc_ast::{ast, token};
@ -33,7 +31,7 @@ pub enum Sugg<'a> {
MaybeParen(Cow<'a, str>),
/// A binary operator expression, including `as`-casts and explicit type
/// coercion.
BinOp(AssocOp, Cow<'a, str>),
BinOp(AssocOp, Cow<'a, str>, Cow<'a, str>),
}
/// Literal constant `0`, for convenience.
@ -46,7 +44,8 @@ pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed(""));
impl Display for Sugg<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
match *self {
Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) | Sugg::BinOp(_, ref s) => s.fmt(f),
Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) => s.fmt(f),
Sugg::BinOp(op, ref lhs, ref rhs) => binop_to_string(op, lhs, rhs).fmt(f),
}
}
}
@ -55,10 +54,8 @@ impl Display for Sugg<'_> {
impl<'a> Sugg<'a> {
/// Prepare a suggestion from an expression.
pub fn hir_opt(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Self> {
snippet_opt(cx, expr.span).map(|snippet| {
let snippet = Cow::Owned(snippet);
Self::hir_from_snippet(expr, snippet)
})
let get_snippet = |span| snippet(cx, span, "");
snippet_opt(cx, expr.span).map(|_| Self::hir_from_snippet(expr, get_snippet))
}
/// Convenience function around `hir_opt` for suggestions with a default
@ -93,9 +90,8 @@ impl<'a> Sugg<'a> {
/// Same as `hir`, but will use the pre expansion span if the `expr` was in a macro.
pub fn hir_with_macro_callsite(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self {
let snippet = snippet_with_macro_callsite(cx, expr.span, default);
Self::hir_from_snippet(expr, snippet)
let get_snippet = |span| snippet_with_macro_callsite(cx, span, default);
Self::hir_from_snippet(expr, get_snippet)
}
/// Same as `hir`, but first walks the span up to the given context. This will result in the
@ -112,24 +108,26 @@ impl<'a> Sugg<'a> {
default: &'a str,
applicability: &mut Applicability,
) -> Self {
let (snippet, in_macro) = snippet_with_context(cx, expr.span, ctxt, default, applicability);
if in_macro {
Sugg::NonParen(snippet)
if expr.span.ctxt() == ctxt {
Self::hir_from_snippet(expr, |span| snippet(cx, span, default))
} else {
Self::hir_from_snippet(expr, snippet)
let snip = snippet_with_applicability(cx, expr.span, default, applicability);
Sugg::NonParen(snip)
}
}
/// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*`
/// function variants of `Sugg`, since these use different snippet functions.
fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self {
fn hir_from_snippet(expr: &hir::Expr<'_>, get_snippet: impl Fn(Span) -> Cow<'a, str>) -> Self {
if let Some(range) = higher::Range::hir(expr) {
let op = match range.limits {
ast::RangeLimits::HalfOpen => AssocOp::DotDot,
ast::RangeLimits::Closed => AssocOp::DotDotEq,
};
return Sugg::BinOp(op, snippet);
let start = range.start.map_or("".into(), |expr| get_snippet(expr.span));
let end = range.end.map_or("".into(), |expr| get_snippet(expr.span));
return Sugg::BinOp(op, start, end);
}
match expr.kind {
@ -139,7 +137,7 @@ impl<'a> Sugg<'a> {
| hir::ExprKind::Let(..)
| hir::ExprKind::Closure(..)
| hir::ExprKind::Unary(..)
| hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
| hir::ExprKind::Match(..) => Sugg::MaybeParen(get_snippet(expr.span)),
hir::ExprKind::Continue(..)
| hir::ExprKind::Yield(..)
| hir::ExprKind::Array(..)
@ -160,12 +158,20 @@ impl<'a> Sugg<'a> {
| hir::ExprKind::Struct(..)
| hir::ExprKind::Tup(..)
| hir::ExprKind::DropTemps(_)
| hir::ExprKind::Err => Sugg::NonParen(snippet),
hir::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
hir::ExprKind::AssignOp(op, ..) => Sugg::BinOp(hirbinop2assignop(op), snippet),
hir::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node.into()), snippet),
hir::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
hir::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
| hir::ExprKind::Err => Sugg::NonParen(get_snippet(expr.span)),
hir::ExprKind::Assign(lhs, rhs, _) => {
Sugg::BinOp(AssocOp::Assign, get_snippet(lhs.span), get_snippet(rhs.span))
},
hir::ExprKind::AssignOp(op, lhs, rhs) => {
Sugg::BinOp(hirbinop2assignop(op), get_snippet(lhs.span), get_snippet(rhs.span))
},
hir::ExprKind::Binary(op, lhs, rhs) => Sugg::BinOp(
AssocOp::from_ast_binop(op.node.into()),
get_snippet(lhs.span),
get_snippet(rhs.span),
),
hir::ExprKind::Cast(lhs, ty) => Sugg::BinOp(AssocOp::As, get_snippet(lhs.span), get_snippet(ty.span)),
hir::ExprKind::Type(lhs, ty) => Sugg::BinOp(AssocOp::Colon, get_snippet(lhs.span), get_snippet(ty.span)),
}
}
@ -173,10 +179,12 @@ impl<'a> Sugg<'a> {
pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
use rustc_ast::ast::RangeLimits;
let snippet = if expr.span.from_expansion() {
snippet_with_macro_callsite(cx, expr.span, default)
} else {
snippet(cx, expr.span, default)
let get_whole_snippet = || {
if expr.span.from_expansion() {
snippet_with_macro_callsite(cx, expr.span, default)
} else {
snippet(cx, expr.span, default)
}
};
match expr.kind {
@ -186,7 +194,7 @@ impl<'a> Sugg<'a> {
| ast::ExprKind::If(..)
| ast::ExprKind::Let(..)
| ast::ExprKind::Unary(..)
| ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
| ast::ExprKind::Match(..) => Sugg::MaybeParen(get_whole_snippet()),
ast::ExprKind::Async(..)
| ast::ExprKind::Block(..)
| ast::ExprKind::Break(..)
@ -215,14 +223,42 @@ impl<'a> Sugg<'a> {
| ast::ExprKind::Array(..)
| ast::ExprKind::While(..)
| ast::ExprKind::Await(..)
| ast::ExprKind::Err => Sugg::NonParen(snippet),
ast::ExprKind::Range(.., RangeLimits::HalfOpen) => Sugg::BinOp(AssocOp::DotDot, snippet),
ast::ExprKind::Range(.., RangeLimits::Closed) => Sugg::BinOp(AssocOp::DotDotEq, snippet),
ast::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
ast::ExprKind::AssignOp(op, ..) => Sugg::BinOp(astbinop2assignop(op), snippet),
ast::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node), snippet),
ast::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
ast::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
| ast::ExprKind::Err => Sugg::NonParen(get_whole_snippet()),
ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::HalfOpen) => Sugg::BinOp(
AssocOp::DotDot,
lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
),
ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::Closed) => Sugg::BinOp(
AssocOp::DotDotEq,
lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
),
ast::ExprKind::Assign(ref lhs, ref rhs, _) => Sugg::BinOp(
AssocOp::Assign,
snippet(cx, lhs.span, default),
snippet(cx, rhs.span, default),
),
ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => Sugg::BinOp(
astbinop2assignop(op),
snippet(cx, lhs.span, default),
snippet(cx, rhs.span, default),
),
ast::ExprKind::Binary(op, ref lhs, ref rhs) => Sugg::BinOp(
AssocOp::from_ast_binop(op.node),
snippet(cx, lhs.span, default),
snippet(cx, rhs.span, default),
),
ast::ExprKind::Cast(ref lhs, ref ty) => Sugg::BinOp(
AssocOp::As,
snippet(cx, lhs.span, default),
snippet(cx, ty.span, default),
),
ast::ExprKind::Type(ref lhs, ref ty) => Sugg::BinOp(
AssocOp::Colon,
snippet(cx, lhs.span, default),
snippet(cx, ty.span, default),
),
}
}
@ -306,17 +342,51 @@ impl<'a> Sugg<'a> {
Sugg::NonParen(format!("({})", sugg).into())
}
},
Sugg::BinOp(_, sugg) => {
if has_enclosing_paren(&sugg) {
Sugg::NonParen(sugg)
} else {
Sugg::NonParen(format!("({})", sugg).into())
}
Sugg::BinOp(op, lhs, rhs) => {
let sugg = binop_to_string(op, &lhs, &rhs);
Sugg::NonParen(format!("({})", sugg).into())
},
}
}
}
/// Generates a string from the operator and both sides.
fn binop_to_string(op: AssocOp, lhs: &str, rhs: &str) -> String {
match op {
AssocOp::Add
| AssocOp::Subtract
| AssocOp::Multiply
| AssocOp::Divide
| AssocOp::Modulus
| AssocOp::LAnd
| AssocOp::LOr
| AssocOp::BitXor
| AssocOp::BitAnd
| AssocOp::BitOr
| AssocOp::ShiftLeft
| AssocOp::ShiftRight
| AssocOp::Equal
| AssocOp::Less
| AssocOp::LessEqual
| AssocOp::NotEqual
| AssocOp::Greater
| AssocOp::GreaterEqual => 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),
}
}
/// Return `true` if `sugg` is enclosed in parenthesis.
fn has_enclosing_paren(sugg: impl AsRef<str>) -> bool {
let mut chars = sugg.as_ref().chars();
@ -391,10 +461,25 @@ impl Neg for Sugg<'_> {
}
}
impl Not for Sugg<'_> {
type Output = Sugg<'static>;
fn not(self) -> Sugg<'static> {
make_unop("!", self)
impl Not for Sugg<'a> {
type Output = Sugg<'a>;
fn not(self) -> Sugg<'a> {
use AssocOp::{Equal, Greater, GreaterEqual, Less, LessEqual, NotEqual};
if let Sugg::BinOp(op, lhs, rhs) = self {
let to_op = match op {
Equal => NotEqual,
NotEqual => Equal,
Less => GreaterEqual,
GreaterEqual => Less,
Greater => LessEqual,
LessEqual => Greater,
_ => return make_unop("!", Sugg::BinOp(op, lhs, rhs)),
};
Sugg::BinOp(to_op, lhs, rhs)
} else {
make_unop("!", self)
}
}
}
@ -463,53 +548,21 @@ pub fn make_assoc(op: AssocOp, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static>
|| is_shift(other) && is_arith(op)
}
let lhs_paren = if let Sugg::BinOp(lop, _) = *lhs {
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 {
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())
let lhs = ParenHelper::new(lhs_paren, lhs).to_string();
let rhs = ParenHelper::new(rhs_paren, rhs).to_string();
Sugg::BinOp(op, lhs.into(), rhs.into())
}
/// Convenience wrapper around `make_assoc` and `AssocOp::from_ast_binop`.
@ -1007,10 +1060,32 @@ mod test {
#[test]
fn binop_maybe_par() {
let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into());
let sugg = Sugg::BinOp(AssocOp::Add, "1".into(), "1".into());
assert_eq!("(1 + 1)", sugg.maybe_par().to_string());
let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1) + (1 + 1)".into());
let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into(), "(1 + 1)".into());
assert_eq!("((1 + 1) + (1 + 1))", sugg.maybe_par().to_string());
}
#[test]
fn not_op() {
use AssocOp::{Add, Equal, Greater, GreaterEqual, LAnd, LOr, Less, LessEqual, NotEqual};
fn test_not(op: AssocOp, correct: &str) {
let sugg = Sugg::BinOp(op, "x".into(), "y".into());
assert_eq!((!sugg).to_string(), correct);
}
// Invert the comparison operator.
test_not(Equal, "x != y");
test_not(NotEqual, "x == y");
test_not(Less, "x >= y");
test_not(LessEqual, "x > y");
test_not(Greater, "x <= y");
test_not(GreaterEqual, "x < y");
// Other operators are inverted like !(..).
test_not(Add, "!(x + y)");
test_not(LAnd, "!(x && y)");
test_not(LOr, "!(x || y)");
}
}