| use crate::rustc_lint::LintContext; |
| use clippy_utils::diagnostics::span_lint_and_sugg; |
| use clippy_utils::source::snippet_with_context; |
| use if_chain::if_chain; |
| use rustc_errors::Applicability; |
| use rustc_hir::{Block, ExprKind}; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::{declare_lint_pass, declare_tool_lint}; |
| |
| declare_clippy_lint! { |
| /// ### What it does |
| /// Looks for blocks of expressions and fires if the last expression returns |
| /// `()` but is not followed by a semicolon. |
| /// |
| /// ### Why is this bad? |
| /// The semicolon might be optional but when extending the block with new |
| /// code, it doesn't require a change in previous last line. |
| /// |
| /// ### Example |
| /// ```no_run |
| /// fn main() { |
| /// println!("Hello world") |
| /// } |
| /// ``` |
| /// Use instead: |
| /// ```no_run |
| /// fn main() { |
| /// println!("Hello world"); |
| /// } |
| /// ``` |
| #[clippy::version = "1.52.0"] |
| pub SEMICOLON_IF_NOTHING_RETURNED, |
| pedantic, |
| "add a semicolon if nothing is returned" |
| } |
| |
| declare_lint_pass!(SemicolonIfNothingReturned => [SEMICOLON_IF_NOTHING_RETURNED]); |
| |
| impl<'tcx> LateLintPass<'tcx> for SemicolonIfNothingReturned { |
| fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) { |
| if_chain! { |
| if !block.span.from_expansion(); |
| if let Some(expr) = block.expr; |
| let t_expr = cx.typeck_results().expr_ty(expr); |
| if t_expr.is_unit(); |
| let mut app = Applicability::MachineApplicable; |
| if let snippet = snippet_with_context(cx, expr.span, block.span.ctxt(), "}", &mut app).0; |
| if !snippet.ends_with('}') && !snippet.ends_with(';'); |
| if cx.sess().source_map().is_multiline(block.span); |
| then { |
| // filter out the desugared `for` loop |
| if let ExprKind::DropTemps(..) = &expr.kind { |
| return; |
| } |
| span_lint_and_sugg( |
| cx, |
| SEMICOLON_IF_NOTHING_RETURNED, |
| expr.span.source_callsite(), |
| "consider adding a `;` to the last statement for consistent formatting", |
| "add a `;` here", |
| format!("{snippet};"), |
| app, |
| ); |
| } |
| } |
| } |
| } |