diff options
| -rw-r--r-- | clippy_lints/src/lib.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/unnecessary_semicolon.rs | 56 | ||||
| -rw-r--r-- | tests/ui/unnecessary_semicolon.edition2021.fixed | 57 | ||||
| -rw-r--r-- | tests/ui/unnecessary_semicolon.edition2021.stderr | 23 | ||||
| -rw-r--r-- | tests/ui/unnecessary_semicolon.edition2024.fixed | 57 | ||||
| -rw-r--r-- | tests/ui/unnecessary_semicolon.edition2024.stderr | 29 | ||||
| -rw-r--r-- | tests/ui/unnecessary_semicolon.rs | 25 |
7 files changed, 243 insertions, 6 deletions
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 7888119567b..85f99a9e055 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -973,6 +973,6 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) { store.register_late_pass(|_| Box::new(unnecessary_literal_bound::UnnecessaryLiteralBound)); store.register_late_pass(move |_| Box::new(arbitrary_source_item_ordering::ArbitrarySourceItemOrdering::new(conf))); store.register_late_pass(|_| Box::new(unneeded_struct_pattern::UnneededStructPattern)); - store.register_late_pass(|_| Box::new(unnecessary_semicolon::UnnecessarySemicolon)); + store.register_late_pass(|_| Box::<unnecessary_semicolon::UnnecessarySemicolon>::default()); // add lints here, do not remove this comment, it's used in `new_lint` } diff --git a/clippy_lints/src/unnecessary_semicolon.rs b/clippy_lints/src/unnecessary_semicolon.rs index 6bc56dffc57..efbc536dcb4 100644 --- a/clippy_lints/src/unnecessary_semicolon.rs +++ b/clippy_lints/src/unnecessary_semicolon.rs @@ -1,8 +1,10 @@ use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::leaks_droppable_temporary_with_limited_lifetime; use rustc_errors::Applicability; -use rustc_hir::{ExprKind, MatchSource, Stmt, StmtKind}; +use rustc_hir::{Block, ExprKind, HirId, MatchSource, Stmt, StmtKind}; use rustc_lint::{LateContext, LateLintPass}; -use rustc_session::declare_lint_pass; +use rustc_session::impl_lint_pass; +use rustc_span::edition::Edition::Edition2021; declare_clippy_lint! { /// ### What it does @@ -33,10 +35,50 @@ declare_clippy_lint! { "unnecessary semicolon after expression returning `()`" } -declare_lint_pass!(UnnecessarySemicolon => [UNNECESSARY_SEMICOLON]); +#[derive(Default)] +pub struct UnnecessarySemicolon { + last_statements: Vec<HirId>, +} + +impl_lint_pass!(UnnecessarySemicolon => [UNNECESSARY_SEMICOLON]); + +impl UnnecessarySemicolon { + /// Enter or leave a block, remembering the last statement of the block. + fn handle_block(&mut self, cx: &LateContext<'_>, block: &Block<'_>, enter: bool) { + // Up to edition 2021, removing the semicolon of the last statement of a block + // may result in the scrutinee temporary values to live longer than the block + // variables. To avoid this problem, we do not lint the last statement of an + // expressionless block. + if cx.tcx.sess.edition() <= Edition2021 + && block.expr.is_none() + && let Some(last_stmt) = block.stmts.last() + { + if enter { + self.last_statements.push(last_stmt.hir_id); + } else { + self.last_statements.pop(); + } + } + } + + /// Checks if `stmt` is the last statement in an expressionless block for edition ≤ 2021. + fn is_last_in_block(&self, stmt: &Stmt<'_>) -> bool { + self.last_statements + .last() + .is_some_and(|last_stmt_id| last_stmt_id == &stmt.hir_id) + } +} + +impl<'tcx> LateLintPass<'tcx> for UnnecessarySemicolon { + fn check_block(&mut self, cx: &LateContext<'_>, block: &Block<'_>) { + self.handle_block(cx, block, true); + } -impl LateLintPass<'_> for UnnecessarySemicolon { - fn check_stmt(&mut self, cx: &LateContext<'_>, stmt: &Stmt<'_>) { + fn check_block_post(&mut self, cx: &LateContext<'_>, block: &Block<'_>) { + self.handle_block(cx, block, false); + } + + fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &Stmt<'tcx>) { // rustfmt already takes care of removing semicolons at the end // of loops. if let StmtKind::Semi(expr) = stmt.kind @@ -48,6 +90,10 @@ impl LateLintPass<'_> for UnnecessarySemicolon { ) && cx.typeck_results().expr_ty(expr) == cx.tcx.types.unit { + if self.is_last_in_block(stmt) && leaks_droppable_temporary_with_limited_lifetime(cx, expr) { + return; + } + let semi_span = expr.span.shrink_to_hi().to(stmt.span.shrink_to_hi()); span_lint_and_sugg( cx, diff --git a/tests/ui/unnecessary_semicolon.edition2021.fixed b/tests/ui/unnecessary_semicolon.edition2021.fixed new file mode 100644 index 00000000000..7a3b79553de --- /dev/null +++ b/tests/ui/unnecessary_semicolon.edition2021.fixed @@ -0,0 +1,57 @@ +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 + +#![warn(clippy::unnecessary_semicolon)] +#![feature(postfix_match)] +#![allow(clippy::single_match)] + +fn no_lint(mut x: u32) -> Option<u32> { + Some(())?; + + { + let y = 3; + dbg!(x + y) + }; + + { + let (mut a, mut b) = (10, 20); + (a, b) = (b + 1, a + 1); + } + + Some(0) +} + +fn main() { + let mut a = 3; + if a == 2 { + println!("This is weird"); + } + //~^ ERROR: unnecessary semicolon + + a.match { + 3 => println!("three"), + _ => println!("not three"), + } + //~^ ERROR: unnecessary semicolon +} + +// This is a problem in edition 2021 and below +fn borrow_issue() { + let v = std::cell::RefCell::new(Some(vec![1])); + match &*v.borrow() { + Some(v) => { + dbg!(v); + }, + None => {}, + }; +} + +fn no_borrow_issue(a: u32, b: u32) { + match Some(a + b) { + Some(v) => { + dbg!(v); + }, + None => {}, + } +} diff --git a/tests/ui/unnecessary_semicolon.edition2021.stderr b/tests/ui/unnecessary_semicolon.edition2021.stderr new file mode 100644 index 00000000000..ccff3308417 --- /dev/null +++ b/tests/ui/unnecessary_semicolon.edition2021.stderr @@ -0,0 +1,23 @@ +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:29:6 + | +LL | }; + | ^ help: remove + | + = note: `-D clippy::unnecessary-semicolon` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::unnecessary_semicolon)]` + +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:35:6 + | +LL | }; + | ^ help: remove + +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:56:6 + | +LL | }; + | ^ help: remove + +error: aborting due to 3 previous errors + diff --git a/tests/ui/unnecessary_semicolon.edition2024.fixed b/tests/ui/unnecessary_semicolon.edition2024.fixed new file mode 100644 index 00000000000..d186d5e7ebc --- /dev/null +++ b/tests/ui/unnecessary_semicolon.edition2024.fixed @@ -0,0 +1,57 @@ +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 + +#![warn(clippy::unnecessary_semicolon)] +#![feature(postfix_match)] +#![allow(clippy::single_match)] + +fn no_lint(mut x: u32) -> Option<u32> { + Some(())?; + + { + let y = 3; + dbg!(x + y) + }; + + { + let (mut a, mut b) = (10, 20); + (a, b) = (b + 1, a + 1); + } + + Some(0) +} + +fn main() { + let mut a = 3; + if a == 2 { + println!("This is weird"); + } + //~^ ERROR: unnecessary semicolon + + a.match { + 3 => println!("three"), + _ => println!("not three"), + } + //~^ ERROR: unnecessary semicolon +} + +// This is a problem in edition 2021 and below +fn borrow_issue() { + let v = std::cell::RefCell::new(Some(vec![1])); + match &*v.borrow() { + Some(v) => { + dbg!(v); + }, + None => {}, + } +} + +fn no_borrow_issue(a: u32, b: u32) { + match Some(a + b) { + Some(v) => { + dbg!(v); + }, + None => {}, + } +} diff --git a/tests/ui/unnecessary_semicolon.edition2024.stderr b/tests/ui/unnecessary_semicolon.edition2024.stderr new file mode 100644 index 00000000000..4e526af2147 --- /dev/null +++ b/tests/ui/unnecessary_semicolon.edition2024.stderr @@ -0,0 +1,29 @@ +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:29:6 + | +LL | }; + | ^ help: remove + | + = note: `-D clippy::unnecessary-semicolon` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::unnecessary_semicolon)]` + +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:35:6 + | +LL | }; + | ^ help: remove + +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:47:6 + | +LL | }; + | ^ help: remove + +error: unnecessary semicolon + --> tests/ui/unnecessary_semicolon.rs:56:6 + | +LL | }; + | ^ help: remove + +error: aborting due to 4 previous errors + diff --git a/tests/ui/unnecessary_semicolon.rs b/tests/ui/unnecessary_semicolon.rs index b6fa4f1c9ce..3028c5b27b3 100644 --- a/tests/ui/unnecessary_semicolon.rs +++ b/tests/ui/unnecessary_semicolon.rs @@ -1,5 +1,10 @@ +//@revisions: edition2021 edition2024 +//@[edition2021] edition:2021 +//@[edition2024] edition:2024 + #![warn(clippy::unnecessary_semicolon)] #![feature(postfix_match)] +#![allow(clippy::single_match)] fn no_lint(mut x: u32) -> Option<u32> { Some(())?; @@ -30,3 +35,23 @@ fn main() { }; //~^ ERROR: unnecessary semicolon } + +// This is a problem in edition 2021 and below +fn borrow_issue() { + let v = std::cell::RefCell::new(Some(vec![1])); + match &*v.borrow() { + Some(v) => { + dbg!(v); + }, + None => {}, + }; +} + +fn no_borrow_issue(a: u32, b: u32) { + match Some(a + b) { + Some(v) => { + dbg!(v); + }, + None => {}, + }; +} |