diff --git a/clippy_lints/src/returns.rs b/clippy_lints/src/returns.rs index bb49985c16256..6c522048b5cf6 100644 --- a/clippy_lints/src/returns.rs +++ b/clippy_lints/src/returns.rs @@ -2,10 +2,14 @@ use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then, span_lin use clippy_utils::source::{snippet_opt, snippet_with_context}; use clippy_utils::sugg::has_enclosing_paren; use clippy_utils::visitors::{for_each_expr_with_closures, Descend}; -use clippy_utils::{fn_def_id, is_from_proc_macro, is_inside_let_else, path_to_local_id, span_find_starting_semi}; +use clippy_utils::{ + fn_def_id, is_from_proc_macro, is_inside_let_else, is_res_lang_ctor, path_res, path_to_local_id, + span_find_starting_semi, +}; use core::ops::ControlFlow; use rustc_errors::Applicability; use rustc_hir::intravisit::FnKind; +use rustc_hir::LangItem::ResultErr; use rustc_hir::{ Block, Body, Expr, ExprKind, FnDecl, HirId, ItemKind, LangItem, MatchSource, Node, OwnerNode, PatKind, QPath, Stmt, StmtKind, @@ -182,7 +186,15 @@ impl<'tcx> LateLintPass<'tcx> for Return { if !in_external_macro(cx.sess(), stmt.span) && let StmtKind::Semi(expr) = stmt.kind && let ExprKind::Ret(Some(ret)) = expr.kind - && let ExprKind::Match(.., MatchSource::TryDesugar(_)) = ret.kind + // return Err(...)? desugars to a match + // over a Err(...).branch() + // which breaks down to a branch call, with the callee being + // the constructor of the Err variant + && let ExprKind::Match(maybe_cons, _, MatchSource::TryDesugar(_)) = ret.kind + && let ExprKind::Call(_, [maybe_result_err]) = maybe_cons.kind + && let ExprKind::Call(maybe_constr, _) = maybe_result_err.kind + && is_res_lang_ctor(cx, path_res(cx, maybe_constr), ResultErr) + // Ensure this is not the final stmt, otherwise removing it would cause a compile error && let OwnerNode::Item(item) = cx.tcx.hir().owner(cx.tcx.hir().get_parent_item(expr.hir_id)) && let ItemKind::Fn(_, _, body) = item.kind diff --git a/tests/ui/needless_return_with_question_mark.fixed b/tests/ui/needless_return_with_question_mark.fixed index 0147c73a94b24..9b7da85266316 100644 --- a/tests/ui/needless_return_with_question_mark.fixed +++ b/tests/ui/needless_return_with_question_mark.fixed @@ -77,3 +77,53 @@ fn issue11616() -> Result<(), ()> { }; Ok(()) } + +fn issue11982() { + mod bar { + pub struct Error; + pub fn foo(_: bool) -> Result<(), Error> { + Ok(()) + } + } + + pub struct Error; + + impl From for Error { + fn from(_: bar::Error) -> Self { + Error + } + } + + fn foo(ok: bool) -> Result<(), Error> { + if !ok { + return bar::foo(ok).map(|_| Ok::<(), Error>(()))?; + }; + Ok(()) + } +} + +fn issue11982_no_conversion() { + mod bar { + pub struct Error; + pub fn foo(_: bool) -> Result<(), Error> { + Ok(()) + } + } + + fn foo(ok: bool) -> Result<(), bar::Error> { + if !ok { + return bar::foo(ok).map(|_| Ok::<(), bar::Error>(()))?; + }; + Ok(()) + } +} + +fn general_return() { + fn foo(ok: bool) -> Result<(), ()> { + let bar = Result::Ok(Result::<(), ()>::Ok(())); + if !ok { + return bar?; + }; + Ok(()) + } +} diff --git a/tests/ui/needless_return_with_question_mark.rs b/tests/ui/needless_return_with_question_mark.rs index 66e1f438f8ce0..68e76d2b6402e 100644 --- a/tests/ui/needless_return_with_question_mark.rs +++ b/tests/ui/needless_return_with_question_mark.rs @@ -77,3 +77,53 @@ fn issue11616() -> Result<(), ()> { }; Ok(()) } + +fn issue11982() { + mod bar { + pub struct Error; + pub fn foo(_: bool) -> Result<(), Error> { + Ok(()) + } + } + + pub struct Error; + + impl From for Error { + fn from(_: bar::Error) -> Self { + Error + } + } + + fn foo(ok: bool) -> Result<(), Error> { + if !ok { + return bar::foo(ok).map(|_| Ok::<(), Error>(()))?; + }; + Ok(()) + } +} + +fn issue11982_no_conversion() { + mod bar { + pub struct Error; + pub fn foo(_: bool) -> Result<(), Error> { + Ok(()) + } + } + + fn foo(ok: bool) -> Result<(), bar::Error> { + if !ok { + return bar::foo(ok).map(|_| Ok::<(), bar::Error>(()))?; + }; + Ok(()) + } +} + +fn general_return() { + fn foo(ok: bool) -> Result<(), ()> { + let bar = Result::Ok(Result::<(), ()>::Ok(())); + if !ok { + return bar?; + }; + Ok(()) + } +}