-use crate::utils::{is_expn_of, match_function_call, paths, span_lint, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg};
+use clippy_utils::macros::FormatArgsExpn;
+use clippy_utils::{is_expn_of, match_function_call, paths};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{BorrowKind, Expr, ExprKind};
+use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
-use syntax::ast::LitKind;
+use rustc_span::sym;
declare_clippy_lint! {
- /// **What it does:** Checks for usage of `write!()` / `writeln()!` which can be
+ /// ### What it does
+ /// Checks for usage of `write!()` / `writeln()!` which can be
/// replaced with `(e)print!()` / `(e)println!()`
///
- /// **Why is this bad?** Using `(e)println! is clearer and more concise
+ /// ### Why is this bad?
+ /// Using `(e)println! is clearer and more concise
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # use std::io::Write;
/// # let bar = "furchtbar";
/// // this would be clearer as `eprintln!("foo: {:?}", bar);`
/// writeln!(&mut std::io::stderr(), "foo: {:?}", bar).unwrap();
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub EXPLICIT_WRITE,
complexity,
"using the `write!()` family of functions instead of the `print!()` family of functions, when using the latter would work"
declare_lint_pass!(ExplicitWrite => [EXPLICIT_WRITE]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ExplicitWrite {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
// match call to unwrap
- if let ExprKind::MethodCall(ref unwrap_fun, _, ref unwrap_args) = expr.kind;
- if unwrap_fun.ident.name == sym!(unwrap);
+ if let ExprKind::MethodCall(unwrap_fun, [write_call], _) = expr.kind;
+ if unwrap_fun.ident.name == sym::unwrap;
// match call to write_fmt
- if !unwrap_args.is_empty();
- if let ExprKind::MethodCall(ref write_fun, _, write_args) =
- unwrap_args[0].kind;
+ if let ExprKind::MethodCall(write_fun, [write_recv, write_arg], _) = write_call.kind;
if write_fun.ident.name == sym!(write_fmt);
// match calls to std::io::stdout() / std::io::stderr ()
- if !write_args.is_empty();
- if let Some(dest_name) = if match_function_call(cx, &write_args[0], &paths::STDOUT).is_some() {
+ if let Some(dest_name) = if match_function_call(cx, write_recv, &paths::STDOUT).is_some() {
Some("stdout")
- } else if match_function_call(cx, &write_args[0], &paths::STDERR).is_some() {
+ } else if match_function_call(cx, write_recv, &paths::STDERR).is_some() {
Some("stderr")
} else {
None
};
+ if let Some(format_args) = FormatArgsExpn::parse(cx, write_arg);
then {
- let write_span = unwrap_args[0].span;
let calling_macro =
// ordering is important here, since `writeln!` uses `write!` internally
- if is_expn_of(write_span, "writeln").is_some() {
+ if is_expn_of(write_call.span, "writeln").is_some() {
Some("writeln")
- } else if is_expn_of(write_span, "write").is_some() {
+ } else if is_expn_of(write_call.span, "write").is_some() {
Some("write")
} else {
None
// We need to remove the last trailing newline from the string because the
// underlying `fmt::write` function doesn't know whether `println!` or `print!` was
// used.
- if let Some(mut write_output) = write_output_string(write_args) {
+ let (used, sugg_mac) = if let Some(macro_name) = calling_macro {
+ (
+ format!("{}!({}(), ...)", macro_name, dest_name),
+ macro_name.replace("write", "print"),
+ )
+ } else {
+ (
+ format!("{}().write_fmt(...)", dest_name),
+ "print".into(),
+ )
+ };
+ let msg = format!("use of `{}.unwrap()`", used);
+ if let [write_output] = *format_args.format_string_parts {
+ let mut write_output = write_output.to_string();
if write_output.ends_with('\n') {
write_output.pop();
}
- if let Some(macro_name) = calling_macro {
- span_lint_and_sugg(
- cx,
- EXPLICIT_WRITE,
- expr.span,
- &format!(
- "use of `{}!({}(), ...).unwrap()`",
- macro_name,
- dest_name
- ),
- "try this",
- format!("{}{}!(\"{}\")", prefix, macro_name.replace("write", "print"), write_output.escape_default()),
- Applicability::MachineApplicable
- );
- } else {
- span_lint_and_sugg(
- cx,
- EXPLICIT_WRITE,
- expr.span,
- &format!("use of `{}().write_fmt(...).unwrap()`", dest_name),
- "try this",
- format!("{}print!(\"{}\")", prefix, write_output.escape_default()),
- Applicability::MachineApplicable
- );
- }
+ let sugg = format!("{}{}!(\"{}\")", prefix, sugg_mac, write_output.escape_default());
+ span_lint_and_sugg(
+ cx,
+ EXPLICIT_WRITE,
+ expr.span,
+ &msg,
+ "try this",
+ sugg,
+ Applicability::MachineApplicable
+ );
} else {
// We don't have a proper suggestion
- if let Some(macro_name) = calling_macro {
- span_lint(
- cx,
- EXPLICIT_WRITE,
- expr.span,
- &format!(
- "use of `{}!({}(), ...).unwrap()`. Consider using `{}{}!` instead",
- macro_name,
- dest_name,
- prefix,
- macro_name.replace("write", "print")
- )
- );
- } else {
- span_lint(
- cx,
- EXPLICIT_WRITE,
- expr.span,
- &format!("use of `{}().write_fmt(...).unwrap()`. Consider using `{}print!` instead", dest_name, prefix),
- );
- }
+ let help = format!("consider using `{}{}!` instead", prefix, sugg_mac);
+ span_lint_and_help(cx, EXPLICIT_WRITE, expr.span, &msg, None, &help);
}
-
}
}
}
}
-
-// Extract the output string from the given `write_args`.
-fn write_output_string(write_args: &[Expr<'_>]) -> Option<String> {
- if_chain! {
- // Obtain the string that should be printed
- if write_args.len() > 1;
- if let ExprKind::Call(_, ref output_args) = write_args[1].kind;
- if !output_args.is_empty();
- if let ExprKind::AddrOf(BorrowKind::Ref, _, ref output_string_expr) = output_args[0].kind;
- if let ExprKind::Array(ref string_exprs) = output_string_expr.kind;
- // we only want to provide an automatic suggestion for simple (non-format) strings
- if string_exprs.len() == 1;
- if let ExprKind::Lit(ref lit) = string_exprs[0].kind;
- if let LitKind::Str(ref write_output, _) = lit.node;
- then {
- return Some(write_output.to_string())
- }
- }
- None
-}
projects / rust.git / blobdiff