2018-09-06 10:33:00 +00:00
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use crate::utils::{snippet, span_lint, span_lint_and_sugg};
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2018-08-28 11:13:42 +00:00
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use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
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2018-07-29 09:04:40 +00:00
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use rustc::{declare_tool_lint, lint_array};
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2018-09-06 10:33:00 +00:00
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use std::borrow::Cow;
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2018-07-22 22:19:07 +00:00
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use syntax::ast::*;
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2018-09-06 10:33:00 +00:00
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use syntax::parse::{parser, token};
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2018-07-22 22:19:07 +00:00
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use syntax::tokenstream::{ThinTokenStream, TokenStream};
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2018-04-05 03:46:39 +00:00
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/// **What it does:** This lint warns when you use `println!("")` to
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/// print a newline.
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///
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/// **Why is this bad?** You should use `println!()`, which is simpler.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// println!("");
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/// ```
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declare_clippy_lint! {
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pub PRINTLN_EMPTY_STRING,
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style,
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"using `println!(\"\")` with an empty string"
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}
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/// **What it does:** This lint warns when you use `print!()` with a format
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/// string that
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/// ends in a newline.
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///
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/// **Why is this bad?** You should use `println!()` instead, which appends the
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/// newline.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// print!("Hello {}!\n", name);
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/// ```
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2018-08-11 22:16:03 +00:00
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/// use println!() instead
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/// ```rust
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/// println!("Hello {}!", name);
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/// ```
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2018-04-05 03:46:39 +00:00
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declare_clippy_lint! {
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pub PRINT_WITH_NEWLINE,
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style,
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2018-08-07 20:01:10 +00:00
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"using `print!()` with a format string that ends in a single newline"
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2018-04-05 03:46:39 +00:00
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}
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/// **What it does:** Checks for printing on *stdout*. The purpose of this lint
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/// is to catch debugging remnants.
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///
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/// **Why is this bad?** People often print on *stdout* while debugging an
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/// application and might forget to remove those prints afterward.
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///
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/// **Known problems:** Only catches `print!` and `println!` calls.
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///
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/// **Example:**
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/// ```rust
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/// println!("Hello world!");
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/// ```
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declare_clippy_lint! {
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pub PRINT_STDOUT,
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restriction,
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"printing on stdout"
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}
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/// **What it does:** Checks for use of `Debug` formatting. The purpose of this
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/// lint is to catch debugging remnants.
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///
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/// **Why is this bad?** The purpose of the `Debug` trait is to facilitate
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/// debugging Rust code. It should not be used in in user-facing output.
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///
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/// **Example:**
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/// ```rust
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/// println!("{:?}", foo);
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/// ```
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declare_clippy_lint! {
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pub USE_DEBUG,
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restriction,
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"use of `Debug`-based formatting"
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}
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/// **What it does:** This lint warns about the use of literals as `print!`/`println!` args.
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///
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/// **Why is this bad?** Using literals as `println!` args is inefficient
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/// (c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
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/// (i.e., just put the literal in the format string)
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///
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/// **Known problems:** Will also warn with macro calls as arguments that expand to literals
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/// -- e.g., `println!("{}", env!("FOO"))`.
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///
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/// **Example:**
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/// ```rust
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/// println!("{}", "foo");
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/// ```
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2018-08-11 22:16:03 +00:00
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/// use the literal without formatting:
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/// ```rust
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/// println!("foo");
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/// ```
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2018-04-05 03:46:39 +00:00
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declare_clippy_lint! {
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pub PRINT_LITERAL,
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style,
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"printing a literal with a format string"
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}
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/// **What it does:** This lint warns when you use `writeln!(buf, "")` to
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/// print a newline.
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///
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/// **Why is this bad?** You should use `writeln!(buf)`, which is simpler.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// writeln!("");
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/// ```
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declare_clippy_lint! {
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pub WRITELN_EMPTY_STRING,
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style,
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"using `writeln!(\"\")` with an empty string"
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}
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/// **What it does:** This lint warns when you use `write!()` with a format
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/// string that
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/// ends in a newline.
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///
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/// **Why is this bad?** You should use `writeln!()` instead, which appends the
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/// newline.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// write!(buf, "Hello {}!\n", name);
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/// ```
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declare_clippy_lint! {
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pub WRITE_WITH_NEWLINE,
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style,
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2018-08-07 20:01:10 +00:00
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"using `write!()` with a format string that ends in a single newline"
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2018-04-05 03:46:39 +00:00
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}
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/// **What it does:** This lint warns about the use of literals as `write!`/`writeln!` args.
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///
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/// **Why is this bad?** Using literals as `writeln!` args is inefficient
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/// (c.f., https://github.com/matthiaskrgr/rust-str-bench) and unnecessary
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/// (i.e., just put the literal in the format string)
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///
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/// **Known problems:** Will also warn with macro calls as arguments that expand to literals
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/// -- e.g., `writeln!(buf, "{}", env!("FOO"))`.
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///
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/// **Example:**
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/// ```rust
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/// writeln!(buf, "{}", "foo");
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/// ```
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declare_clippy_lint! {
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pub WRITE_LITERAL,
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style,
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"writing a literal with a format string"
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}
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#[derive(Copy, Clone, Debug)]
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pub struct Pass;
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impl LintPass for Pass {
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fn get_lints(&self) -> LintArray {
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lint_array!(
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PRINT_WITH_NEWLINE,
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PRINTLN_EMPTY_STRING,
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PRINT_STDOUT,
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USE_DEBUG,
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PRINT_LITERAL,
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WRITE_WITH_NEWLINE,
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WRITELN_EMPTY_STRING,
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WRITE_LITERAL
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)
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}
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}
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2018-07-22 22:19:07 +00:00
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impl EarlyLintPass for Pass {
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2018-07-23 11:01:12 +00:00
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fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &Mac) {
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2018-07-22 22:19:07 +00:00
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if mac.node.path == "println" {
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span_lint(cx, PRINT_STDOUT, mac.span, "use of `println!`");
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2018-08-16 16:20:06 +00:00
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if let Some(fmtstr) = check_tts(cx, &mac.node.tts, false).0 {
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2018-07-22 22:19:07 +00:00
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if fmtstr == "" {
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span_lint_and_sugg(
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cx,
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PRINTLN_EMPTY_STRING,
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mac.span,
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"using `println!(\"\")`",
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"replace it with",
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"println!()".to_string(),
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);
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2018-04-05 03:46:39 +00:00
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}
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}
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2018-07-22 22:19:07 +00:00
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} else if mac.node.path == "print" {
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span_lint(cx, PRINT_STDOUT, mac.span, "use of `print!`");
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2018-08-16 16:20:06 +00:00
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if let Some(fmtstr) = check_tts(cx, &mac.node.tts, false).0 {
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2018-08-07 20:01:10 +00:00
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if fmtstr.ends_with("\\n") && !fmtstr.ends_with("\\n\\n") {
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2018-09-06 10:33:00 +00:00
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span_lint(
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cx,
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PRINT_WITH_NEWLINE,
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mac.span,
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"using `print!()` with a format string that ends in a \
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single newline, consider using `println!()` instead",
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);
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2018-04-05 03:46:39 +00:00
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}
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}
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2018-07-22 22:19:07 +00:00
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} else if mac.node.path == "write" {
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2018-08-16 16:20:06 +00:00
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if let Some(fmtstr) = check_tts(cx, &mac.node.tts, true).0 {
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2018-08-07 20:01:10 +00:00
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if fmtstr.ends_with("\\n") && !fmtstr.ends_with("\\n\\n") {
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2018-09-06 10:33:00 +00:00
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span_lint(
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cx,
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WRITE_WITH_NEWLINE,
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mac.span,
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"using `write!()` with a format string that ends in a \
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single newline, consider using `writeln!()` instead",
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);
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2018-04-05 03:46:39 +00:00
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}
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}
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2018-07-22 22:19:07 +00:00
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} else if mac.node.path == "writeln" {
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2018-08-16 16:20:06 +00:00
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let check_tts = check_tts(cx, &mac.node.tts, true);
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if let Some(fmtstr) = check_tts.0 {
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2018-07-22 22:19:07 +00:00
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if fmtstr == "" {
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2018-09-06 10:33:00 +00:00
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let suggestion = check_tts
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.1
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.map_or(Cow::Borrowed("v"), |expr| snippet(cx, expr.span, "v"));
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2018-08-20 12:03:13 +00:00
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2018-07-22 22:19:07 +00:00
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span_lint_and_sugg(
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cx,
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WRITELN_EMPTY_STRING,
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mac.span,
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2018-08-20 13:50:15 +00:00
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format!("using `writeln!({}, \"\")`", suggestion).as_str(),
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2018-07-22 22:19:07 +00:00
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"replace it with",
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2018-08-20 13:33:43 +00:00
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format!("writeln!({})", suggestion),
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2018-07-22 22:19:07 +00:00
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);
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2018-04-05 03:46:39 +00:00
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}
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}
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}
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}
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}
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2018-08-16 16:20:06 +00:00
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fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &ThinTokenStream, is_write: bool) -> (Option<String>, Option<Expr>) {
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2018-07-22 22:19:07 +00:00
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let tts = TokenStream::from(tts.clone());
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2018-09-06 10:33:00 +00:00
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let mut parser = parser::Parser::new(&cx.sess.parse_sess, tts, None, false, false);
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2018-08-20 12:03:13 +00:00
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let mut expr: Option<Expr> = None;
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if is_write {
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2018-08-20 13:33:43 +00:00
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expr = match parser.parse_expr().map_err(|mut err| err.cancel()) {
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Ok(p) => Some(p.into_inner()),
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Err(_) => return (None, None),
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2018-08-20 12:03:13 +00:00
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};
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// might be `writeln!(foo)`
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2018-08-20 13:33:43 +00:00
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if parser.expect(&token::Comma).map_err(|mut err| err.cancel()).is_err() {
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2018-08-20 12:03:13 +00:00
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return (None, expr);
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}
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}
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2018-08-16 16:20:06 +00:00
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2018-08-20 13:33:43 +00:00
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let fmtstr = match parser.parse_str().map_err(|mut err| err.cancel()) {
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Ok(token) => token.0.to_string(),
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Err(_) => return (None, expr),
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2018-08-20 12:03:13 +00:00
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};
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2018-07-22 22:19:07 +00:00
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use fmt_macros::*;
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let tmp = fmtstr.clone();
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let mut args = vec![];
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let mut fmt_parser = Parser::new(&tmp, None);
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while let Some(piece) = fmt_parser.next() {
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if !fmt_parser.errors.is_empty() {
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2018-08-16 16:20:06 +00:00
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return (None, expr);
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2018-04-05 03:46:39 +00:00
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}
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2018-07-22 22:19:07 +00:00
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if let Piece::NextArgument(arg) = piece {
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if arg.format.ty == "?" {
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// FIXME: modify rustc's fmt string parser to give us the current span
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span_lint(cx, USE_DEBUG, parser.prev_span, "use of `Debug`-based formatting");
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2018-04-05 03:46:39 +00:00
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}
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2018-07-22 22:19:07 +00:00
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args.push(arg);
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2018-04-05 03:46:39 +00:00
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}
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}
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2018-09-06 10:33:00 +00:00
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let lint = if is_write { WRITE_LITERAL } else { PRINT_LITERAL };
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2018-07-22 22:19:07 +00:00
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let mut idx = 0;
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loop {
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if !parser.eat(&token::Comma) {
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assert!(parser.eat(&token::Eof));
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2018-08-16 16:20:06 +00:00
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return (Some(fmtstr), expr);
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2018-07-22 22:19:07 +00:00
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}
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2018-08-20 13:33:43 +00:00
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let token_expr = match parser.parse_expr().map_err(|mut err| err.cancel()) {
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Ok(expr) => expr,
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Err(_) => return (Some(fmtstr), None),
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2018-08-20 12:03:13 +00:00
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};
|
2018-07-23 11:01:12 +00:00
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const SIMPLE: FormatSpec<'_> = FormatSpec {
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2018-07-22 22:19:07 +00:00
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fill: None,
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align: AlignUnknown,
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flags: 0,
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precision: CountImplied,
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width: CountImplied,
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ty: "",
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};
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2018-08-20 12:03:13 +00:00
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match &token_expr.node {
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2018-07-22 22:19:07 +00:00
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ExprKind::Lit(_) => {
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let mut all_simple = true;
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let mut seen = false;
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for arg in &args {
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match arg.position {
|
2018-09-06 10:33:00 +00:00
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ArgumentImplicitlyIs(n) | ArgumentIs(n) => if n == idx {
|
2018-07-22 22:19:07 +00:00
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all_simple &= arg.format == SIMPLE;
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seen = true;
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},
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ArgumentNamed(_) => {},
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}
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}
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|
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if all_simple && seen {
|
2018-08-20 12:03:13 +00:00
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span_lint(cx, lint, token_expr.span, "literal with an empty format string");
|
2018-07-22 22:19:07 +00:00
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}
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idx += 1;
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},
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ExprKind::Assign(lhs, rhs) => {
|
2018-07-25 21:31:17 +00:00
|
|
|
if let ExprKind::Lit(_) = rhs.node {
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|
if let ExprKind::Path(_, p) = &lhs.node {
|
|
|
|
let mut all_simple = true;
|
|
|
|
let mut seen = false;
|
|
|
|
for arg in &args {
|
|
|
|
match arg.position {
|
2018-09-06 10:33:00 +00:00
|
|
|
ArgumentImplicitlyIs(_) | ArgumentIs(_) => {},
|
2018-07-25 21:31:17 +00:00
|
|
|
ArgumentNamed(name) => if *p == name {
|
|
|
|
seen = true;
|
|
|
|
all_simple &= arg.format == SIMPLE;
|
|
|
|
},
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if all_simple && seen {
|
|
|
|
span_lint(cx, lint, rhs.span, "literal with an empty format string");
|
2018-07-22 22:19:07 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
},
|
|
|
|
_ => idx += 1,
|
2018-04-21 18:24:55 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|