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https://github.com/rust-lang/rust-clippy
synced 2024-11-24 05:33:27 +00:00
Removed map_err suggestion in lint, and updated lint documentation example
This commit is contained in:
Ricky
parent
337729137b
commit
2387f68e43
2 changed files with 60 additions and 62 deletions
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@ -1,6 +1,6 @@
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use crate::utils::span_lint_and_sugg;
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use rustc_errors::Applicability;
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use rustc_hir::{CaptureBy, Expr, ExprKind, PatKind, QPath};
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use crate::utils::span_lint_and_help;
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use rustc_hir::{CaptureBy, Expr, ExprKind, PatKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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@ -12,33 +12,58 @@ declare_clippy_lint! {
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// Before:
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/// ```rust
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/// use std::convert::TryFrom;
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///
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/// #[derive(Debug)]
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/// enum Errors {
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/// Ignore
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///}
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///fn main() -> Result<(), Errors> {
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/// Ignored
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/// }
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///
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/// let x = u32::try_from(-123_i32);
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/// fn divisible_by_3(inp: i32) -> Result<u32, Errors> {
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/// let i = u32::try_from(inp).map_err(|_| Errors::Ignored)?;
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///
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/// println!("{:?}", x.map_err(|_| Errors::Ignore));
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/// Ok(i)
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/// }
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/// ```
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///
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/// Ok(())
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///}
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/// ```
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/// Use instead:
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/// ```rust
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/// enum Errors {
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/// WithContext(TryFromIntError)
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///}
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///fn main() -> Result<(), Errors> {
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/// After:
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/// ```rust
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/// use std::convert::TryFrom;
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/// use std::num::TryFromIntError;
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/// use std::fmt;
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/// use std::error::Error;
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///
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/// let x = u32::try_from(-123_i32);
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/// #[derive(Debug)]
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/// enum ParseError {
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/// Indivisible {
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/// source: TryFromIntError,
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/// input: String,
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/// }
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/// }
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///
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/// println!("{:?}", x.map_err(|e| Errors::WithContext(e)));
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/// impl fmt::Display for ParseError {
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/// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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/// match &self {
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/// ParseError::Indivisible{source: _, input} => write!(f, "Error: {}", input)
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/// }
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/// }
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/// }
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///
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/// Ok(())
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///}
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/// impl Error for ParseError {}
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///
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/// impl ParseError {
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/// fn new(source: TryFromIntError, input: String) -> ParseError {
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/// ParseError::Indivisible{source, input}
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/// }
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/// }
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///
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/// fn divisible_by_3(inp: i32) -> Result<u32, ParseError> {
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/// let i = u32::try_from(inp).map_err(|e| ParseError::new(e, e.to_string()))?;
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///
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/// Ok(i)
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/// }
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/// ```
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pub MAP_ERR_IGNORE,
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style,
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@ -69,44 +94,16 @@ impl<'tcx> LateLintPass<'tcx> for MapErrIgnore {
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if closure_body.params.len() == 1 {
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// make sure that parameter is the wild token (`_`)
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if let PatKind::Wild = closure_body.params[0].pat.kind {
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// Check the value of the closure to see if we can build the enum we are throwing away
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// the error for make sure this is a Path
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if let ExprKind::Path(q_path) = &closure_body.value.kind {
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// this should be a resolved path, only keep the path field
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if let QPath::Resolved(_, path) = q_path {
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// finally get the idents for each path segment collect them as a string and
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// join them with the path separator ("::"")
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let closure_fold: String = path
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.segments
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.iter()
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.map(|x| x.ident.as_str().to_string())
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.collect::<Vec<String>>()
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.join("::");
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//Span the body of the closure (the |...| bit) and suggest the fix by taking
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// the error and encapsulating it in the enum
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span_lint_and_sugg(
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cx,
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MAP_ERR_IGNORE,
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body_span,
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"`map_err` has thrown away the original error",
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"Allow the error enum to encapsulate the original error",
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format!("|e| {}(e)", closure_fold),
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Applicability::HasPlaceholders,
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);
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}
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} else {
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//If we cannot build the enum in a human readable way just suggest not throwing way
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// the error
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span_lint_and_sugg(
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cx,
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MAP_ERR_IGNORE,
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body_span,
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"`map_err` has thrown away the original error",
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"Allow the error enum to encapsulate the original error",
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"|e|".to_string(),
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Applicability::HasPlaceholders,
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);
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}
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// span the area of the closure capture and warn that the
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// original error will be thrown away
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span_lint_and_help(
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cx,
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MAP_ERR_IGNORE,
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body_span,
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"`map_else(|_|...` ignores the original error",
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None,
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"Consider wrapping the error in an enum variant",
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);
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}
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}
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}
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@ -1,10 +1,11 @@
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error: `map_err` has thrown away the original error
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error: `map_else(|_|...` ignores the original error
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--> $DIR/map_err.rs:21:32
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LL | println!("{:?}", x.map_err(|_| Errors::Ignored));
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| ^^^ help: Allow the error enum to encapsulate the original error: `|e| Errors::Ignored(e)`
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| ^^^
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= note: `-D clippy::map-err-ignore` implied by `-D warnings`
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= help: Consider wrapping the error in an enum variant
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error: aborting due to previous error
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