53 lines
2.1 KiB
Rust
53 lines
2.1 KiB
Rust
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use crate::lint::{EarlyLintPass, LintPass, EarlyContext, LintArray, LintContext};
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use syntax::ast::{Stmt, StmtKind, ExprKind};
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use syntax::errors::Applicability;
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declare_lint! {
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pub REDUNDANT_SEMICOLON,
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Warn,
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"detects unnecessary trailing semicolons"
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}
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declare_lint_pass!(RedundantSemicolon => [REDUNDANT_SEMICOLON]);
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impl EarlyLintPass for RedundantSemicolon {
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fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &Stmt) {
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if let StmtKind::Semi(expr) = &stmt.node {
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if let ExprKind::Tup(ref v) = &expr.node {
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if v.is_empty() {
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// Strings of excess semicolons are encoded as empty tuple expressions
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// during the parsing stage, so we check for empty tuple expressions
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// which span only semicolons
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if let Ok(source_str) = cx.sess().source_map().span_to_snippet(stmt.span) {
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if source_str.chars().all(|c| c == ';') {
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let multiple = (stmt.span.hi() - stmt.span.lo()).0 > 1;
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let msg = if multiple {
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"unnecessary trailing semicolons"
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} else {
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"unnecessary trailing semicolon"
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};
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let mut err = cx.struct_span_lint(
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REDUNDANT_SEMICOLON,
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stmt.span,
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&msg
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);
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let suggest_msg = if multiple {
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"remove these semicolons"
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} else {
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"remove this semicolon"
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};
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err.span_suggestion(
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stmt.span,
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&suggest_msg,
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String::new(),
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Applicability::MaybeIncorrect
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);
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err.emit();
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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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}
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