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3353: float support added for mistyped_literal_suffixes lint r=mikerite a=Maxgy

I implemented the mistyped_literal_suffixes lint for float literals.

```
#![allow(unused_variables)]

fn main() {
    let x = 1E2_32;
    let x = 75.22_64;
}
```
Given the above, the additional check suggests the variables to be written as `let x = 1E2_f32` and `let x = 75.22_f64`.

Fixes rust-lang#3167 

Co-authored-by: Maxwell Anderson <[email protected]>
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@bors @Zaechus
bors[bot] and Zaechus committed Nov 5, 2018
2 parents d8b4269 + 3e0de17 commit 7e417d4
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156 changes: 94 additions & 62 deletions clippy_lints/src/literal_representation.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,16 +7,15 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.


//! Lints concerned with the grouping of digits with underscores in integral or
//! floating-point literal expressions.
use crate::rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass, in_external_macro, LintContext};
use crate::rustc::lint::{in_external_macro, EarlyContext, EarlyLintPass, LintArray, LintContext, LintPass};
use crate::rustc::{declare_tool_lint, lint_array};
use if_chain::if_chain;
use crate::syntax::ast::*;
use crate::syntax_pos;
use crate::utils::{snippet_opt, span_lint_and_sugg};
use if_chain::if_chain;

/// **What it does:** Warns if a long integral or floating-point constant does
/// not contain underscores.
Expand All @@ -41,9 +40,9 @@ declare_clippy_lint! {
/// **Why is this bad?** This is most probably a typo
///
/// **Known problems:**
/// - Recommends a signed suffix, even though the number might be too big and an unsigned
/// - Recommends a signed suffix, even though the number might be too big and an unsigned
/// suffix is required
/// - Does not match on `_128` since that is a valid grouping for decimal and octal numbers
/// - Does not match on `_128` since that is a valid grouping for decimal and octal numbers
///
/// **Example:**
///
Expand Down Expand Up @@ -168,21 +167,21 @@ impl<'a> DigitInfo<'a> {
let len = sans_prefix.len();
let mut last_d = '\0';
for (d_idx, d) in sans_prefix.char_indices() {
let suffix_start = if last_d == '_' {
d_idx - 1
} else {
d_idx
};
if float && (d == 'f' || d == 'e' || d == 'E') ||
!float && (d == 'i' || d == 'u' || is_possible_suffix_index(&sans_prefix, suffix_start, len)) {
let (digits, suffix) = sans_prefix.split_at(suffix_start);
return Self {
digits,
radix,
prefix,
suffix: Some(suffix),
float,
};
let suffix_start = if last_d == '_' { d_idx - 1 } else { d_idx };
if float
&& (d == 'f'
|| is_possible_float_suffix_index(&sans_prefix, suffix_start, len)
|| ((d == 'E' || d == 'e') && !has_possible_float_suffix(&sans_prefix)))
|| !float && (d == 'i' || d == 'u' || is_possible_suffix_index(&sans_prefix, suffix_start, len))
{
let (digits, suffix) = sans_prefix.split_at(suffix_start);
return Self {
digits,
radix,
prefix,
suffix: Some(suffix),
float,
};
}
last_d = d
}
Expand Down Expand Up @@ -224,18 +223,44 @@ impl<'a> DigitInfo<'a> {
.map(|chunk| chunk.iter().collect())
.collect::<Vec<String>>()
.join("_");
let suffix_hint = match self.suffix {
Some(suffix) if is_mistyped_float_suffix(suffix) => format!("_f{}", &suffix[1..]),
Some(suffix) => suffix.to_string(),
None => String::new(),
};
format!("{}.{}{}", int_part_hint, frac_part_hint, suffix_hint)
} else if self.float && (self.digits.contains('E') || self.digits.contains('e')) {
let which_e = if self.digits.contains('E') { 'E' } else { 'e' };
let parts: Vec<&str> = self.digits.split(which_e).collect();
let filtered_digits_vec_0 = parts[0].chars().filter(|&c| c != '_').rev().collect::<Vec<_>>();
let filtered_digits_vec_1 = parts[1].chars().filter(|&c| c != '_').rev().collect::<Vec<_>>();
let before_e_hint = filtered_digits_vec_0
.chunks(group_size)
.map(|chunk| chunk.iter().rev().collect())
.rev()
.collect::<Vec<String>>()
.join("_");
let after_e_hint = filtered_digits_vec_1
.chunks(group_size)
.map(|chunk| chunk.iter().rev().collect())
.rev()
.collect::<Vec<String>>()
.join("_");
let suffix_hint = match self.suffix {
Some(suffix) if is_mistyped_float_suffix(suffix) => format!("_f{}", &suffix[1..]),
Some(suffix) => suffix.to_string(),
None => String::new(),
};
format!(
"{}.{}{}",
int_part_hint,
frac_part_hint,
self.suffix.unwrap_or("")
"{}{}{}{}{}",
self.prefix.unwrap_or(""),
before_e_hint,
which_e,
after_e_hint,
suffix_hint
)
} else {
let filtered_digits_vec = self.digits
.chars()
.filter(|&c| c != '_')
.rev()
.collect::<Vec<_>>();
let filtered_digits_vec = self.digits.chars().filter(|&c| c != '_').rev().collect::<Vec<_>>();
let mut hint = filtered_digits_vec
.chunks(group_size)
.map(|chunk| chunk.iter().rev().collect())
Expand All @@ -248,18 +273,11 @@ impl<'a> DigitInfo<'a> {
hint = format!("{:0>4}{}", &hint[..nb_digits_to_fill], &hint[nb_digits_to_fill..]);
}
let suffix_hint = match self.suffix {
Some(suffix) if is_mistyped_suffix(suffix) => {
format!("_i{}", &suffix[1..])
},
Some(suffix) if is_mistyped_suffix(suffix) => format!("_i{}", &suffix[1..]),
Some(suffix) => suffix.to_string(),
None => String::new()
None => String::new(),
};
format!(
"{}{}{}",
self.prefix.unwrap_or(""),
hint,
suffix_hint
)
format!("{}{}{}", self.prefix.unwrap_or(""), hint, suffix_hint)
}
}
}
Expand All @@ -269,22 +287,20 @@ enum WarningType {
InconsistentDigitGrouping,
LargeDigitGroups,
DecimalRepresentation,
MistypedLiteralSuffix
MistypedLiteralSuffix,
}

impl WarningType {
crate fn display(&self, grouping_hint: &str, cx: &EarlyContext<'_>, span: syntax_pos::Span) {
match self {
WarningType::MistypedLiteralSuffix => {
span_lint_and_sugg(
cx,
MISTYPED_LITERAL_SUFFIXES,
span,
"mistyped literal suffix",
"did you mean to write",
grouping_hint.to_string()
)
},
WarningType::MistypedLiteralSuffix => span_lint_and_sugg(
cx,
MISTYPED_LITERAL_SUFFIXES,
span,
"mistyped literal suffix",
"did you mean to write",
grouping_hint.to_string(),
),
WarningType::UnreadableLiteral => span_lint_and_sugg(
cx,
UNREADABLE_LITERAL,
Expand Down Expand Up @@ -380,7 +396,7 @@ impl LiteralDigitGrouping {

// Lint integral and fractional parts separately, and then check consistency of digit
// groups if both pass.
let _ = Self::do_lint(parts[0], None)
let _ = Self::do_lint(parts[0], digit_info.suffix)
.map(|integral_group_size| {
if parts.len() > 1 {
// Lint the fractional part of literal just like integral part, but reversed.
Expand All @@ -391,11 +407,11 @@ impl LiteralDigitGrouping {
fractional_group_size,
parts[0].len(),
parts[1].len());
if !consistent {
WarningType::InconsistentDigitGrouping.display(&digit_info.grouping_hint(),
cx,
lit.span);
}
if !consistent {
WarningType::InconsistentDigitGrouping.display(&digit_info.grouping_hint(),
cx,
lit.span);
}
})
.map_err(|warning_type| warning_type.display(&digit_info.grouping_hint(),
cx,
Expand Down Expand Up @@ -494,9 +510,7 @@ impl EarlyLintPass for LiteralRepresentation {

impl LiteralRepresentation {
pub fn new(threshold: u64) -> Self {
Self {
threshold,
}
Self { threshold }
}
fn check_lit(self, cx: &EarlyContext<'_>, lit: &Lit) {
// Lint integral literals.
Expand Down Expand Up @@ -529,7 +543,12 @@ impl LiteralRepresentation {
fn do_lint(digits: &str) -> Result<(), WarningType> {
if digits.len() == 1 {
// Lint for 1 digit literals, if someone really sets the threshold that low
if digits == "1" || digits == "2" || digits == "4" || digits == "8" || digits == "3" || digits == "7"
if digits == "1"
|| digits == "2"
|| digits == "4"
|| digits == "8"
|| digits == "3"
|| digits == "7"
|| digits == "F"
{
return Err(WarningType::DecimalRepresentation);
Expand All @@ -538,6 +557,7 @@ impl LiteralRepresentation {
// Lint for Literals with a hex-representation of 2 or 3 digits
let f = &digits[0..1]; // first digit
let s = &digits[1..]; // suffix

// Powers of 2
if ((f.eq("1") || f.eq("2") || f.eq("4") || f.eq("8")) && s.chars().all(|c| c == '0'))
// Powers of 2 minus 1
Expand All @@ -550,6 +570,7 @@ impl LiteralRepresentation {
let f = &digits[0..1]; // first digit
let m = &digits[1..digits.len() - 1]; // middle digits, except last
let s = &digits[1..]; // suffix

// Powers of 2 with a margin of +15/-16
if ((f.eq("1") || f.eq("2") || f.eq("4") || f.eq("8")) && m.chars().all(|c| c == '0'))
|| ((f.eq("1") || f.eq("3") || f.eq("7") || f.eq("F")) && m.chars().all(|c| c == 'F'))
Expand All @@ -570,6 +591,17 @@ fn is_mistyped_suffix(suffix: &str) -> bool {
}

fn is_possible_suffix_index(lit: &str, idx: usize, len: usize) -> bool {
((len > 3 && idx == len - 3) || (len > 2 && idx == len - 2)) &&
is_mistyped_suffix(lit.split_at(idx).1)
((len > 3 && idx == len - 3) || (len > 2 && idx == len - 2)) && is_mistyped_suffix(lit.split_at(idx).1)
}

fn is_mistyped_float_suffix(suffix: &str) -> bool {
["_32", "_64"].contains(&suffix)
}

fn is_possible_float_suffix_index(lit: &str, idx: usize, len: usize) -> bool {
(len > 3 && idx == len - 3) && is_mistyped_float_suffix(lit.split_at(idx).1)
}

fn has_possible_float_suffix(lit: &str) -> bool {
lit.ends_with("_32") || lit.ends_with("_64")
}
10 changes: 7 additions & 3 deletions tests/ui/literals.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,6 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.




#![warn(clippy::mixed_case_hex_literals)]
#![warn(clippy::unseparated_literal_suffix)]
#![warn(clippy::zero_prefixed_literal)]
Expand Down Expand Up @@ -64,4 +61,11 @@ fn main() {
let fail21 = 4___16;
let fail22 = 3__4___23;
let fail23 = 3__16___23;

let fail24 = 12.34_64;
let fail25 = 1E2_32;
let fail26 = 43E7_64;
let fail27 = 243E17_32;
let fail28 = 241251235E723_64;
let fail29 = 42279.911_32;
}
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