2018-11-27 14:13:57 +00:00
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use crate::utils::{snippet_with_applicability, span_lint, span_lint_and_sugg};
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2018-12-29 15:04:45 +00:00
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use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
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2019-04-08 20:43:55 +00:00
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use rustc::{declare_lint_pass, declare_tool_lint};
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2018-12-29 15:04:45 +00:00
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use rustc_errors::Applicability;
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2018-11-20 13:06:29 +00:00
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use std::borrow::Cow;
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2018-12-29 15:04:45 +00:00
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use syntax::ast::*;
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use syntax::parse::{parser, token};
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2019-02-18 05:53:30 +00:00
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use syntax::tokenstream::{TokenStream, TokenTree};
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2018-04-05 03:46:39 +00:00
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declare_clippy_lint! {
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2019-03-05 16:50:33 +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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2018-04-05 03:46:39 +00:00
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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # let name = "World";
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2019-03-05 16:50:33 +00:00
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/// print!("Hello {}!\n", name);
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/// ```
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/// use println!() instead
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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # let name = "World";
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2019-03-05 16:50:33 +00:00
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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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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2018-04-05 03:46:39 +00:00
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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2018-04-05 03:46:39 +00:00
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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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/// 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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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # use std::fmt::Write;
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/// # let mut buf = String::new();
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2019-03-05 22:23:50 +00:00
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/// writeln!(buf, "");
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2019-03-05 16:50:33 +00:00
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/// ```
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2018-04-05 03:46:39 +00:00
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pub WRITELN_EMPTY_STRING,
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style,
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2019-03-05 22:23:50 +00:00
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"using `writeln!(buf, \"\")` with an empty string"
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2018-04-05 03:46:39 +00:00
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}
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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # use std::fmt::Write;
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/// # let mut buf = String::new();
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/// # let name = "World";
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2019-03-05 16:50:33 +00:00
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/// write!(buf, "Hello {}!\n", name);
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/// ```
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2018-04-05 03:46:39 +00:00
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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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declare_clippy_lint! {
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2019-03-05 16:50:33 +00:00
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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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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # use std::fmt::Write;
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/// # let mut buf = String::new();
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2019-03-05 16:50:33 +00:00
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/// writeln!(buf, "{}", "foo");
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/// ```
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2018-04-05 03:46:39 +00:00
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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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2019-04-08 20:43:55 +00:00
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declare_lint_pass!(Write => [
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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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2018-04-05 03:46:39 +00:00
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2019-04-08 20:43:55 +00:00
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impl EarlyLintPass for Write {
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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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2018-11-27 14:13:57 +00:00
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Applicability::MachineApplicable,
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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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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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2019-02-18 05:53:30 +00:00
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if let (Some(fmtstr), _, is_raw) = check_tts(cx, &mac.node.tts, false) {
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2019-02-18 16:39:23 +00:00
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if check_newlines(&fmtstr, is_raw) {
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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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2019-02-18 05:53:30 +00:00
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if let (Some(fmtstr), _, is_raw) = check_tts(cx, &mac.node.tts, true) {
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2019-02-18 16:39:23 +00:00
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if check_newlines(&fmtstr, is_raw) {
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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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2018-11-27 14:13:57 +00:00
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let mut applicability = Applicability::MachineApplicable;
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let suggestion = check_tts.1.map_or_else(
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move || {
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applicability = Applicability::HasPlaceholders;
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Cow::Borrowed("v")
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},
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move |expr| snippet_with_applicability(cx, expr.span, "v", &mut applicability),
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);
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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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2018-11-27 14:13:57 +00:00
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applicability,
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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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2018-11-27 14:11:13 +00:00
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/// Checks the arguments of `print[ln]!` and `write[ln]!` calls. It will return a tuple of two
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2019-02-18 05:53:30 +00:00
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/// options and a bool. The first part of the tuple is `format_str` of the macros. The second part
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/// of the tuple is in the `write[ln]!` case the expression the `format_str` should be written to.
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/// The final part is a boolean flag indicating if the string is a raw string.
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2018-11-27 14:11:13 +00:00
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///
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/// Example:
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///
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/// Calling this function on
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2019-03-09 07:51:23 +00:00
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/// ```rust
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/// # use std::fmt::Write;
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/// # let mut buf = String::new();
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/// # let something = "something";
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/// writeln!(buf, "string to write: {}", something);
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2018-11-27 14:11:13 +00:00
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/// ```
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/// will return
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/// ```rust,ignore
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2019-02-18 05:53:30 +00:00
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/// (Some("string to write: {}"), Some(buf), false)
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2018-11-27 14:11:13 +00:00
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/// ```
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2019-02-18 05:53:30 +00:00
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fn check_tts<'a>(cx: &EarlyContext<'a>, tts: &TokenStream, is_write: bool) -> (Option<String>, Option<Expr>, bool) {
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2018-12-29 15:04:45 +00:00
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use fmt_macros::*;
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2019-01-20 08:14:23 +00:00
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let tts = tts.clone();
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2019-02-18 05:53:30 +00:00
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let mut is_raw = false;
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if let TokenStream(Some(tokens)) = &tts {
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for token in tokens.iter() {
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if let (TokenTree::Token(_, token::Token::Literal(lit, _)), _) = token {
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match lit {
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token::Lit::Str_(_) => break,
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token::Lit::StrRaw(_, _) => {
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is_raw = true;
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break;
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},
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_ => {},
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}
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}
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}
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}
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2018-09-06 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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2019-02-18 05:53:30 +00:00
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Err(_) => return (None, None, is_raw),
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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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2019-02-18 05:53:30 +00:00
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return (None, expr, is_raw);
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2018-08-20 12:03:13 +00:00
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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(),
|
2019-02-18 05:53:30 +00:00
|
|
|
Err(_) => return (None, expr, is_raw),
|
2018-08-20 12:03:13 +00:00
|
|
|
};
|
2018-07-22 22:19:07 +00:00
|
|
|
let tmp = fmtstr.clone();
|
|
|
|
let mut args = vec![];
|
2018-12-27 10:19:20 +00:00
|
|
|
let mut fmt_parser = Parser::new(&tmp, None, Vec::new(), false);
|
2018-07-22 22:19:07 +00:00
|
|
|
while let Some(piece) = fmt_parser.next() {
|
|
|
|
if !fmt_parser.errors.is_empty() {
|
2019-02-18 05:53:30 +00:00
|
|
|
return (None, expr, is_raw);
|
2018-04-05 03:46:39 +00:00
|
|
|
}
|
2018-07-22 22:19:07 +00:00
|
|
|
if let Piece::NextArgument(arg) = piece {
|
|
|
|
if arg.format.ty == "?" {
|
|
|
|
// FIXME: modify rustc's fmt string parser to give us the current span
|
|
|
|
span_lint(cx, USE_DEBUG, parser.prev_span, "use of `Debug`-based formatting");
|
2018-04-05 03:46:39 +00:00
|
|
|
}
|
2018-07-22 22:19:07 +00:00
|
|
|
args.push(arg);
|
2018-04-05 03:46:39 +00:00
|
|
|
}
|
|
|
|
}
|
2018-09-06 10:33:00 +00:00
|
|
|
let lint = if is_write { WRITE_LITERAL } else { PRINT_LITERAL };
|
2018-07-22 22:19:07 +00:00
|
|
|
let mut idx = 0;
|
|
|
|
loop {
|
2018-07-23 11:01:12 +00:00
|
|
|
const SIMPLE: FormatSpec<'_> = FormatSpec {
|
2018-07-22 22:19:07 +00:00
|
|
|
fill: None,
|
|
|
|
align: AlignUnknown,
|
|
|
|
flags: 0,
|
|
|
|
precision: CountImplied,
|
|
|
|
width: CountImplied,
|
|
|
|
ty: "",
|
|
|
|
};
|
2018-10-08 00:08:20 +00:00
|
|
|
if !parser.eat(&token::Comma) {
|
2019-02-18 05:53:30 +00:00
|
|
|
return (Some(fmtstr), expr, is_raw);
|
2018-10-08 00:08:20 +00:00
|
|
|
}
|
|
|
|
let token_expr = match parser.parse_expr().map_err(|mut err| err.cancel()) {
|
|
|
|
Ok(expr) => expr,
|
2019-02-18 05:53:30 +00:00
|
|
|
Err(_) => return (Some(fmtstr), None, is_raw),
|
2018-10-08 00:08:20 +00:00
|
|
|
};
|
2018-08-20 12:03:13 +00:00
|
|
|
match &token_expr.node {
|
2018-07-22 22:19:07 +00:00
|
|
|
ExprKind::Lit(_) => {
|
|
|
|
let mut all_simple = true;
|
|
|
|
let mut seen = false;
|
|
|
|
for arg in &args {
|
|
|
|
match arg.position {
|
2018-11-27 20:14:15 +00:00
|
|
|
ArgumentImplicitlyIs(n) | ArgumentIs(n) => {
|
|
|
|
if n == idx {
|
|
|
|
all_simple &= arg.format == SIMPLE;
|
|
|
|
seen = true;
|
|
|
|
}
|
2018-07-22 22:19:07 +00:00
|
|
|
},
|
|
|
|
ArgumentNamed(_) => {},
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if all_simple && seen {
|
2018-08-20 12:03:13 +00:00
|
|
|
span_lint(cx, lint, token_expr.span, "literal with an empty format string");
|
2018-07-22 22:19:07 +00:00
|
|
|
}
|
|
|
|
idx += 1;
|
|
|
|
},
|
|
|
|
ExprKind::Assign(lhs, rhs) => {
|
2018-07-25 21:31:17 +00:00
|
|
|
if let ExprKind::Lit(_) = rhs.node {
|
|
|
|
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(_) => {},
|
2018-11-27 20:14:15 +00:00
|
|
|
ArgumentNamed(name) => {
|
|
|
|
if *p == name {
|
|
|
|
seen = true;
|
|
|
|
all_simple &= arg.format == SIMPLE;
|
|
|
|
}
|
2018-07-25 21:31:17 +00:00
|
|
|
},
|
|
|
|
}
|
|
|
|
}
|
|
|
|
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
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2018-12-11 06:28:25 +00:00
|
|
|
|
|
|
|
// Checks if `s` constains a single newline that terminates it
|
2019-02-18 16:39:23 +00:00
|
|
|
// Literal and escaped newlines are both checked (only literal for raw strings)
|
|
|
|
fn check_newlines(s: &str, is_raw: bool) -> bool {
|
|
|
|
if s.ends_with('\n') {
|
|
|
|
return true;
|
|
|
|
} else if is_raw {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
2018-12-11 06:28:25 +00:00
|
|
|
if s.len() < 2 {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
let bytes = s.as_bytes();
|
|
|
|
if bytes[bytes.len() - 2] != b'\\' || bytes[bytes.len() - 1] != b'n' {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
|
|
|
let mut escaping = false;
|
|
|
|
for (index, &byte) in bytes.iter().enumerate() {
|
|
|
|
if escaping {
|
|
|
|
if byte == b'n' {
|
|
|
|
return index == bytes.len() - 1;
|
|
|
|
}
|
|
|
|
escaping = false;
|
|
|
|
} else if byte == b'\\' {
|
|
|
|
escaping = true;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
false
|
|
|
|
}
|