bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Use structured suggestions for for_loop_over_fallibles lint

Browse source
This commit is contained in:
Maybe Waffle 2022-07-18 21:08:59 +04:00
parent fa380a82a5
commit d030ba52e2
1 changed files with 14 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

22
compiler/rustc_lint/src/for_loop_over_fallibles.rs
View file

@ -1,6 +1,7 @@
use crate::{LateContext, LateLintPass, LintContext};
use hir::{Expr, Pat};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_middle::ty;
use rustc_span::sym;
@ -65,18 +66,24 @@ impl<'tcx> LateLintPass<'tcx> for ForLoopOverFallibles {
_ => return,
};
let Ok(pat_snip) = cx.sess().source_map().span_to_snippet(pat.span) else { return };
let Ok(arg_snip) = cx.sess().source_map().span_to_snippet(arg.span) else { return };
let help_string = format!(
"consider replacing `for {pat_snip} in {arg_snip}` with `if let {var}({pat_snip}) = {arg_snip}`"
);
let msg = format!(
"for loop over `{arg_snip}`, which is {article} `{ty}`. This is more readably written as an `if let` statement",
);
cx.struct_span_lint(FOR_LOOP_OVER_FALLIBLES, arg.span, |diag| {
diag.build(msg).help(help_string).emit()
diag.build(msg)
.multipart_suggestion_verbose(
"consider using `if let` to clear intent",
vec![
// NB can't use `until` here because `expr.span` and `pat.span` have different syntax contexts
(expr.span.with_hi(pat.span.lo()), format!("if let {var}(")),
(pat.span.between(arg.span), format!(") = ")),
],
Applicability::MachineApplicable,
)
.emit()
})
}
}
@ -89,11 +96,10 @@ fn extract_for_loop<'tcx>(expr: &Expr<'tcx>) -> Option<(&'tcx Pat<'tcx>, &'tcx E
&& let [stmt] = block.stmts
&& let hir::StmtKind::Expr(e) = stmt.kind
&& let hir::ExprKind::Match(_, [_, some_arm], _) = e.kind
&& let hir::PatKind::Struct(_, [field], _) = some_arm.pat.kind
&& let hir::PatKind::Struct(_, [field], _) = some_arm.pat.kind
{
Some((field.pat, arg))
} else {
None
}
}
}