#3016 [WIP] Implement feedback and suggestions

This commit is contained in:
Lachezar Lechev 2018-08-20 14:03:13 +02:00
parent 6cb94630fb
commit 3015987f27

View file

@ -3,7 +3,7 @@ use rustc::{declare_lint, lint_array};
use syntax::ast::*;
use syntax::tokenstream::{ThinTokenStream, TokenStream};
use syntax::parse::{token, parser};
use crate::utils::{span_lint, span_lint_and_sugg};
use crate::utils::{span_lint, span_lint_and_sugg, snippet};
/// **What it does:** This lint warns when you use `println!("")` to
/// print a newline.
@ -212,13 +212,15 @@ impl EarlyLintPass for Pass {
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("v", |expr| snippet(cx, expr.span, "v").into_owned().as_str());
span_lint_and_sugg(
cx,
WRITELN_EMPTY_STRING,
mac.span,
format!("using `writeln!({}, \"\")`", check_tts.1).as_str(),
format!("using writeln!({}, \"\")", suggestion).as_str(),
"replace it with",
format!("using `writeln!({})`", check_tts.1),
format!("writeln!({})", "v"),
);
}
}
@ -235,15 +237,23 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
false,
false,
);
let mut expr: Option<Expr> = None;
if is_write {
// skip the initial write target
let expr: Option<Expr> = match parser.parse_expr().map_err(|mut err| err.cancel()).ok() {
Some(p) => Some(p.into_vec().0),
None => None,
expr = match parser.parse_expr().map_err(|mut err| err.cancel()).ok() {
Some(p) => Some(p.and_then(|expr| expr)),
None => return (None, None),
};
// might be `writeln!(foo)`
parser.expect(&token::Comma).map_err(|mut err| err.cancel()).ok()?;
if let None = parser.expect(&token::Comma).map_err(|mut err| err.cancel()).ok() {
return (None, expr);
}
}
let fmtstr = parser.parse_str().map_err(|mut err| err.cancel()).ok()?.0.to_string();
let fmtstr = match parser.parse_str().map_err(|mut err| err.cancel()).ok() {
Some(token) => token.0.to_string(),
None => return (None, expr),
};
use fmt_macros::*;
let tmp = fmtstr.clone();
let mut args = vec![];
@ -271,7 +281,10 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
assert!(parser.eat(&token::Eof));
return (Some(fmtstr), expr);
}
let expr = parser.parse_expr().map_err(|mut err| err.cancel()).ok()?;
let token_expr = match parser.parse_expr().map_err(|mut err| err.cancel()).ok() {
Some(expr) => expr,
None => return (Some(fmtstr), None),
};
const SIMPLE: FormatSpec<'_> = FormatSpec {
fill: None,
align: AlignUnknown,
@ -280,7 +293,7 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
width: CountImplied,
ty: "",
};
match &expr.node {
match &token_expr.node {
ExprKind::Lit(_) => {
let mut all_simple = true;
let mut seen = false;
@ -296,7 +309,7 @@ fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -
}
}
if all_simple && seen {
span_lint(cx, lint, expr.span, "literal with an empty format string");
span_lint(cx, lint, token_expr.span, "literal with an empty format string");
}
idx += 1;
},