Added detailled suggs for new case
This commit is contained in:
Pierre-Andre Gagnon
parent
e0e51e4189
commit
6165cccf7e
@ -1,13 +1,13 @@
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use crate::utils::{
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contains_return, in_macro, is_type_diagnostic_item, match_qpath, paths, return_ty, snippet, span_lint_and_sugg,
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span_lint_and_then, visitors::find_all_ret_expressions,
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contains_return, in_macro, match_qpath, paths, return_ty, snippet, span_lint_and_then,
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visitors::find_all_ret_expressions,
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};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::intravisit::FnKind;
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use rustc_hir::{Body, ExprKind, FnDecl, HirId, Impl, ItemKind, Node};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty::subst::GenericArgKind;
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use rustc_middle::ty;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::symbol::sym;
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use rustc_span::Span;
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@ -85,33 +85,23 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
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}
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}
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// Check if return type is Option or Result. If neither, abort.
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let return_ty = return_ty(cx, hir_id);
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let (return_type_label, path) = if is_type_diagnostic_item(cx, return_ty, sym::option_type) {
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("Option", &paths::OPTION_SOME)
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} else if is_type_diagnostic_item(cx, return_ty, sym::result_type) {
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("Result", &paths::RESULT_OK)
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} else {
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return;
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};
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// Take the first inner type of the Option or Result. If can't, abort.
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let inner_ty = if_chain! {
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// Skip Option or Result and take the first outermost inner type.
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if let Some(inner_ty) = return_ty.walk().nth(1);
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if let GenericArgKind::Type(inner_ty) = inner_ty.unpack();
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then {
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inner_ty
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// Get the wrapper and inner types, if can't, abort.
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let (return_type_label, path, inner_type) = if let ty::Adt(adt_def, subst) = return_ty(cx, hir_id).kind() {
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if cx.tcx.is_diagnostic_item(sym::option_type, adt_def.did) {
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("Option", &paths::OPTION_SOME, subst.type_at(0))
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} else if cx.tcx.is_diagnostic_item(sym::result_type, adt_def.did) {
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("Result", &paths::RESULT_OK, subst.type_at(0))
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} else {
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return;
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}
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} else {
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return;
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};
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// Check if all return expression respect the following condition and collect them.
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let mut suggs = Vec::new();
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let can_sugg = find_all_ret_expressions(cx, &body.value, |ret_expr| {
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if_chain! {
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// Abort if in macro.
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if !in_macro(ret_expr.span);
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// Check if a function call.
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if let ExprKind::Call(ref func, ref args) = ret_expr.kind;
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@ -119,12 +109,20 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
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if let ExprKind::Path(ref qpath) = func.kind;
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// Check if OPTION_SOME or RESULT_OK, depending on return type.
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if match_qpath(qpath, path);
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// Make sure the function call has only one argument.
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if args.len() == 1;
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// Make sure the function argument does not contain a return expression.
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if !contains_return(&args[0]);
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then {
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suggs.push((ret_expr.span, snippet(cx, args[0].span.source_callsite(), "..").to_string()));
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suggs.push(
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(
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ret_expr.span,
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if inner_type.is_unit() {
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"".to_string()
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} else {
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snippet(cx, args[0].span.source_callsite(), "..").to_string()
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}
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)
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);
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true
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} else {
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false
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@ -133,42 +131,36 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
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});
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if can_sugg && !suggs.is_empty() {
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// Issue 6640: If the inner type is Unit, emit lint similar to clippy::unused_unit.
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if inner_ty.is_unit() {
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span_lint_and_sugg(
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cx,
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UNNECESSARY_WRAPS,
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fn_decl.output.span(),
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"unneeded wrapped unit return type",
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format!("remove the `-> {}<[...]>`", return_type_label).as_str(),
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String::new(),
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Applicability::MaybeIncorrect,
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);
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let (lint_msg, return_type_suggestion_msg, return_type_suggestion) = if inner_type.is_unit() {
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(
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"this function's return value is unnecessary".to_string(),
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"remove the return type...".to_string(),
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snippet(cx, fn_decl.output.span(), "..").to_string(),
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)
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} else {
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span_lint_and_then(
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cx,
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UNNECESSARY_WRAPS,
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span,
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(
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format!(
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"this function's return value is unnecessarily wrapped by `{}`",
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return_type_label
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)
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.as_str(),
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|diag| {
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diag.span_suggestion(
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fn_decl.output.span(),
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format!("remove `{}` from the return type...", return_type_label).as_str(),
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inner_ty.to_string(),
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Applicability::MaybeIncorrect,
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);
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diag.multipart_suggestion(
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"...and change the returning expressions",
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suggs,
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Applicability::MaybeIncorrect,
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);
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},
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),
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format!("remove `{}` from the return type...", return_type_label),
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inner_type.to_string(),
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)
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};
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span_lint_and_then(cx, UNNECESSARY_WRAPS, span, lint_msg.as_str(), |diag| {
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diag.span_suggestion(
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fn_decl.output.span(),
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return_type_suggestion_msg.as_str(),
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return_type_suggestion,
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Applicability::MaybeIncorrect,
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);
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}
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diag.multipart_suggestion(
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"...and then change the returning expressions",
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suggs,
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Applicability::MaybeIncorrect,
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);
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});
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}
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}
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}
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@ -15,7 +15,7 @@ help: remove `Option` from the return type...
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LL | fn func1(a: bool, b: bool) -> i32 {
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| ^^^
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help: ...and change the returning expressions
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help: ...and then change the returning expressions
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LL | return 42;
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LL | }
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@ -41,7 +41,7 @@ help: remove `Option` from the return type...
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LL | fn func2(a: bool, b: bool) -> i32 {
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| ^^^
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help: ...and change the returning expressions
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help: ...and then change the returning expressions
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LL | return 10;
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LL | }
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@ -63,7 +63,7 @@ help: remove `Option` from the return type...
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LL | fn func5() -> i32 {
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| ^^^
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help: ...and change the returning expressions
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help: ...and then change the returning expressions
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LL | 1
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@ -80,7 +80,7 @@ help: remove `Result` from the return type...
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LL | fn func7() -> i32 {
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| ^^^
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help: ...and change the returning expressions
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help: ...and then change the returning expressions
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LL | 1
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@ -97,22 +97,62 @@ help: remove `Option` from the return type...
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LL | fn func12() -> i32 {
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| ^^^
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help: ...and change the returning expressions
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help: ...and then change the returning expressions
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LL | 1
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error: unneeded wrapped unit return type
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--> $DIR/unnecessary_wraps.rs:120:38
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error: this function's return value is unnecessary
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--> $DIR/unnecessary_wraps.rs:120:1
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LL | / fn issue_6640_1(a: bool, b: bool) -> Option<()> {
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LL | | if a && b {
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LL | | return Some(());
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LL | | }
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... |
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LL | | }
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LL | | }
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| |_^
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help: remove the return type...
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LL | fn issue_6640_1(a: bool, b: bool) -> Option<()> {
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| ^^^^^^^^^^ help: remove the `-> Option<[...]>`
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| ^^^^^^^^^^
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help: ...and then change the returning expressions
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LL | return ;
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LL | }
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LL | if a {
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LL | Some(());
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LL |
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LL | } else {
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...
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error: unneeded wrapped unit return type
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--> $DIR/unnecessary_wraps.rs:133:38
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error: this function's return value is unnecessary
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--> $DIR/unnecessary_wraps.rs:133:1
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LL | / fn issue_6640_2(a: bool, b: bool) -> Result<(), i32> {
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LL | | if a && b {
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LL | | return Ok(());
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LL | | }
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... |
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LL | | }
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LL | | }
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| |_^
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help: remove the return type...
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LL | fn issue_6640_2(a: bool, b: bool) -> Result<(), i32> {
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| ^^^^^^^^^^^^^^^ help: remove the `-> Result<[...]>`
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| ^^^^^^^^^^^^^^^
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help: ...and then change the returning expressions
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LL | return ;
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LL | }
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LL | if a {
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LL |
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LL | } else {
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LL | return ;
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error: aborting due to 7 previous errors
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