Add suggestion for explicit_write lint

This commit is contained in:
Philipp Hansch 2018-11-23 08:18:23 +01:00
parent e2608fc272
commit c4c9d9fc62
No known key found for this signature in database
GPG key ID: B6FA06A6E0E2665B
4 changed files with 75 additions and 46 deletions

View file

@ -10,8 +10,8 @@
use crate::rustc::hir::*;
use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use crate::rustc::{declare_tool_lint, lint_array};
use crate::utils::opt_def_id;
use crate::utils::{is_expn_of, match_def_path, resolve_node, span_lint};
use crate::syntax::ast::LitKind;
use crate::utils::{is_expn_of, match_def_path, opt_def_id, resolve_node, span_lint, span_lint_and_sugg};
use if_chain::if_chain;
/// **What it does:** Checks for usage of `write!()` / `writeln()!` which can be
@ -51,6 +51,12 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
if unwrap_args.len() > 0;
if let ExprKind::MethodCall(ref write_fun, _, ref write_args) =
unwrap_args[0].node;
// Obtain the string that should be printed
if let ExprKind::Call(_, ref output_args) = write_args[1].node;
if let ExprKind::AddrOf(_, ref output_string_expr) = output_args[0].node;
if let ExprKind::Array(ref string_exprs) = output_string_expr.node;
if let ExprKind::Lit(ref lit) = string_exprs[0].node;
if let LitKind::Str(ref write_output, _) = lit.node;
if write_fun.ident.name == "write_fmt";
// match calls to std::io::stdout() / std::io::stderr ()
if write_args.len() > 0;
@ -81,29 +87,35 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
} else {
""
};
// We need to remove the last trailing newline from the string because the
// underlying `fmt::write` function doesn't know wether `println!` or `print!` was
// used.
let mut write_output: String = write_output.to_string();
if write_output.ends_with('\n') {
write_output.truncate(write_output.len() - 1)
}
if let Some(macro_name) = calling_macro {
span_lint(
span_lint_and_sugg(
cx,
EXPLICIT_WRITE,
expr.span,
&format!(
"use of `{}!({}(), ...).unwrap()`. Consider using `{}{}!` instead",
"use of `{}!({}(), ...).unwrap()`",
macro_name,
dest_name,
prefix,
macro_name.replace("write", "print")
)
dest_name
),
"try this",
format!("{}{}!(\"{}\")", prefix, macro_name.replace("write", "print"), write_output.escape_default())
);
} else {
span_lint(
span_lint_and_sugg(
cx,
EXPLICIT_WRITE,
expr.span,
&format!(
"use of `{}().write_fmt(...).unwrap()`. Consider using `{}print!` instead",
dest_name,
prefix,
)
&format!("use of `{}().write_fmt(...).unwrap()`", dest_name),
"try this",
format!("{}print!(\"{}\")", prefix, write_output.escape_default())
);
}
}

View file

@ -14,6 +14,7 @@
#![feature(slice_patterns)]
#![feature(stmt_expr_attributes)]
#![feature(range_contains)]
#![feature(str_escape)]
#![allow(clippy::missing_docs_in_private_items)]
#![recursion_limit = "256"]
#![warn(rust_2018_idioms, trivial_casts, trivial_numeric_casts)]

View file

@ -27,6 +27,10 @@ fn main() {
writeln!(std::io::stderr(), "test").unwrap();
std::io::stdout().write_fmt(format_args!("test")).unwrap();
std::io::stderr().write_fmt(format_args!("test")).unwrap();
// including newlines
writeln!(std::io::stdout(), "test\ntest").unwrap();
writeln!(std::io::stderr(), "test\ntest").unwrap();
}
// these should not warn, different destination
{

View file

@ -1,40 +1,52 @@
error: use of `write!(stdout(), ...).unwrap()`. Consider using `print!` instead
--> $DIR/explicit_write.rs:24:9
error: use of `write!(stdout(), ...).unwrap()`
--> $DIR/explicit_write.rs:28:9
|
24 | write!(std::io::stdout(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
28 | write!(std::io::stdout(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `print!("test")`
|
= note: `-D clippy::explicit-write` implied by `-D warnings`
error: use of `write!(stderr(), ...).unwrap()`. Consider using `eprint!` instead
--> $DIR/explicit_write.rs:25:9
|
25 | write!(std::io::stderr(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: use of `writeln!(stdout(), ...).unwrap()`. Consider using `println!` instead
--> $DIR/explicit_write.rs:26:9
|
26 | writeln!(std::io::stdout(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: use of `writeln!(stderr(), ...).unwrap()`. Consider using `eprintln!` instead
--> $DIR/explicit_write.rs:27:9
|
27 | writeln!(std::io::stderr(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: use of `stdout().write_fmt(...).unwrap()`. Consider using `print!` instead
--> $DIR/explicit_write.rs:28:9
|
28 | std::io::stdout().write_fmt(format_args!("test")).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: use of `stderr().write_fmt(...).unwrap()`. Consider using `eprint!` instead
error: use of `write!(stderr(), ...).unwrap()`
--> $DIR/explicit_write.rs:29:9
|
29 | std::io::stderr().write_fmt(format_args!("test")).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
29 | write!(std::io::stderr(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprint!("test")`
error: aborting due to 6 previous errors
error: use of `writeln!(stdout(), ...).unwrap()`
--> $DIR/explicit_write.rs:30:9
|
30 | writeln!(std::io::stdout(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `println!("test")`
error: use of `writeln!(stderr(), ...).unwrap()`
--> $DIR/explicit_write.rs:31:9
|
31 | writeln!(std::io::stderr(), "test").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("test")`
error: use of `stdout().write_fmt(...).unwrap()`
--> $DIR/explicit_write.rs:32:9
|
32 | std::io::stdout().write_fmt(format_args!("test")).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `print!("test")`
error: use of `stderr().write_fmt(...).unwrap()`
--> $DIR/explicit_write.rs:33:9
|
33 | std::io::stderr().write_fmt(format_args!("test")).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprint!("test")`
error: use of `writeln!(stdout(), ...).unwrap()`
--> $DIR/explicit_write.rs:36:9
|
36 | writeln!(std::io::stdout(), "test/ntest").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `println!("test/ntest")`
error: use of `writeln!(stderr(), ...).unwrap()`
--> $DIR/explicit_write.rs:37:9
|
37 | writeln!(std::io::stderr(), "test/ntest").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("test/ntest")`
error: aborting due to 8 previous errors