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Merge pull request #3138 from matthiaskrgr/3126__no_warn_multi_newline 

print_with_newline / write_with_newline: don't warn about string with several `\n`s in them.
This commit is contained in:
Oliver S̶c̶h̶n̶e̶i̶d̶e̶r Scherer 2018-09-06 17:41:23 +02:00 committed by GitHub
parent 3262f9283f a0f56edfc3
commit 8af69273d0
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 37 additions and 31 deletions
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64
clippy_lints/src/write.rs
View File

@ -1,10 +1,10 @@
use crate::utils::{snippet, span_lint, span_lint_and_sugg};
use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
use rustc::{declare_tool_lint, lint_array};
use syntax::ast::*;
use syntax::tokenstream::{ThinTokenStream, TokenStream};
use syntax::parse::{token, parser};
use std::borrow::Cow;
use crate::utils::{span_lint, span_lint_and_sugg, snippet};
use syntax::ast::*;
use syntax::parse::{parser, token};
use syntax::tokenstream::{ThinTokenStream, TokenStream};
/// **What it does:** This lint warns when you use `println!("")` to
/// print a newline.
@ -195,25 +195,41 @@ impl EarlyLintPass for Pass {
} else if mac.node.path == "print" {
span_lint(cx, PRINT_STDOUT, mac.span, "use of `print!`");
if let Some(fmtstr) = check_tts(cx, &mac.node.tts, false).0 {
if fmtstr.ends_with("\\n") && !fmtstr.ends_with("\\n\\n") {
span_lint(cx, PRINT_WITH_NEWLINE, mac.span,
"using `print!()` with a format string that ends in a \
single newline, consider using `println!()` instead");
if fmtstr.ends_with("\\n") &&
// don't warn about strings with several `\n`s (#3126)
fmtstr.matches("\\n").count() == 1
{
span_lint(
cx,
PRINT_WITH_NEWLINE,
mac.span,
"using `print!()` with a format string that ends in a \
single newline, consider using `println!()` instead",
);
}
}
} else if mac.node.path == "write" {
if let Some(fmtstr) = check_tts(cx, &mac.node.tts, true).0 {
if fmtstr.ends_with("\\n") && !fmtstr.ends_with("\\n\\n") {
span_lint(cx, WRITE_WITH_NEWLINE, mac.span,
"using `write!()` with a format string that ends in a \
single newline, consider using `writeln!()` instead");
if fmtstr.ends_with("\\n") &&
// don't warn about strings with several `\n`s (#3126)
fmtstr.matches("\\n").count() == 1
{
span_lint(
cx,
WRITE_WITH_NEWLINE,
mac.span,
"using `write!()` with a format string that ends in a \
single newline, consider using `writeln!()` instead",
);
}
}
} else if mac.node.path == "writeln" {
let check_tts = check_tts(cx, &mac.node.tts, true);
if let Some(fmtstr) = check_tts.0 {
if fmtstr == "" {
let suggestion = check_tts.1.map_or(Cow::Borrowed("v"), |expr| snippet(cx, expr.span, "v"));
let suggestion = check_tts
.1
.map_or(Cow::Borrowed("v"), |expr| snippet(cx, expr.span, "v"));
span_lint_and_sugg(
cx,
@ -231,13 +247,7 @@ impl EarlyLintPass for Pass {
fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -> (Option<String>, Option<Expr>) {
let tts = TokenStream::from(tts.clone());
let mut parser = parser::Parser::new(
&cx.sess.parse_sess,
tts,
None,
false,
false,
);
let mut parser = parser::Parser::new(&cx.sess.parse_sess, tts, None, false, false);
let mut expr: Option<Expr> = None;
if is_write {
expr = match parser.parse_expr().map_err(|mut err| err.cancel()) {
@ -270,11 +280,7 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
args.push(arg);
}
}
let lint = if is_write {
WRITE_LITERAL
} else {
PRINT_LITERAL
};
let lint = if is_write { WRITE_LITERAL } else { PRINT_LITERAL };
let mut idx = 0;
loop {
if !parser.eat(&token::Comma) {
@ -299,9 +305,7 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
let mut seen = false;
for arg in &args {
match arg.position {
| ArgumentImplicitlyIs(n)
| ArgumentIs(n)
=> if n == idx {
ArgumentImplicitlyIs(n) | ArgumentIs(n) => if n == idx {
all_simple &= arg.format == SIMPLE;
seen = true;
},
@ -320,9 +324,7 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
let mut seen = false;
for arg in &args {
match arg.position {
| ArgumentImplicitlyIs(_)
| ArgumentIs(_)
=> {},
ArgumentImplicitlyIs(_) | ArgumentIs(_) => {},
ArgumentNamed(name) => if *p == name {
seen = true;
all_simple &= arg.format == SIMPLE;

2
tests/ui/print_with_newline.rs
View File

@ -21,4 +21,6 @@ fn main() {
print!("\n\n");
print!("like eof\n\n");
print!("Hello {} {}\n\n", "world", "#2");
println!("\ndon't\nwarn\nfor\nmultiple\nnewlines\n"); // #3126
println!("\nbla\n\n"); // #3126
}

2
tests/ui/write_with_newline.rs
View File

@ -26,4 +26,6 @@ fn main() {
write!(&mut v, "\n\n");
write!(&mut v, "like eof\n\n");
write!(&mut v, "Hello {} {}\n\n", "world", "#2");
writeln!(&mut v, "\ndon't\nwarn\nfor\nmultiple\nnewlines\n"); // #3126
writeln!(&mut v, "\nbla\n\n"); // #3126
}