c857cbeb06
We now lint on code like this:
```rust
fn main() {
fn foo() {};
struct Bar {};
}
```
Previously, this caused warnings in Cargo, so it was disabled.
63 lines
1.9 KiB
Rust
63 lines
1.9 KiB
Rust
use crate::{EarlyContext, EarlyLintPass, LintContext};
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use rustc_ast::{Block, StmtKind};
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use rustc_errors::Applicability;
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use rustc_span::Span;
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declare_lint! {
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/// The `redundant_semicolons` lint detects unnecessary trailing
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/// semicolons.
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///
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/// ### Example
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///
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/// ```rust
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/// let _ = 123;;
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/// ```
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///
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/// {{produces}}
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///
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/// ### Explanation
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///
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/// Extra semicolons are not needed, and may be removed to avoid confusion
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/// and visual clutter.
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pub REDUNDANT_SEMICOLONS,
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Warn,
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"detects unnecessary trailing semicolons"
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}
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declare_lint_pass!(RedundantSemicolons => [REDUNDANT_SEMICOLONS]);
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impl EarlyLintPass for RedundantSemicolons {
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fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) {
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let mut seq = None;
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for stmt in block.stmts.iter() {
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match (&stmt.kind, &mut seq) {
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(StmtKind::Empty, None) => seq = Some((stmt.span, false)),
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(StmtKind::Empty, Some(seq)) => *seq = (seq.0.to(stmt.span), true),
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(_, seq) => maybe_lint_redundant_semis(cx, seq),
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}
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}
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maybe_lint_redundant_semis(cx, &mut seq);
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}
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}
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fn maybe_lint_redundant_semis(cx: &EarlyContext<'_>, seq: &mut Option<(Span, bool)>) {
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if let Some((span, multiple)) = seq.take() {
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// FIXME: Find a better way of ignoring the trailing
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// semicolon from macro expansion
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if span == rustc_span::DUMMY_SP {
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return;
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}
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cx.struct_span_lint(REDUNDANT_SEMICOLONS, span, |lint| {
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let (msg, rem) = if multiple {
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("unnecessary trailing semicolons", "remove these semicolons")
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} else {
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("unnecessary trailing semicolon", "remove this semicolon")
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};
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lint.build(msg)
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.span_suggestion(span, rem, String::new(), Applicability::MaybeIncorrect)
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.emit();
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});
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}
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}
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