Use more let chain

Author: GuillaumeGomez

src/librustdoc/clean/cfg.rs

@@ -164,10 +164,10 @@ impl Cfg {
     /// Renders the configuration for human display, as a short HTML description.
     pub(crate) fn render_short_html(&self) -> String {
         let mut msg = Display(self, Format::ShortHtml).to_string();
-        if self.should_capitalize_first_letter() {
-            if let Some(i) = msg.find(|c: char| c.is_ascii_alphanumeric()) {
-                msg[i..i + 1].make_ascii_uppercase();
-            }
+        if self.should_capitalize_first_letter() &&
+            let Some(i) = msg.find(|c: char| c.is_ascii_alphanumeric())
+        {
+            msg[i..i + 1].make_ascii_uppercase();
         }
         msg
     }

src/librustdoc/clean/inline.rs

@@ -390,18 +390,17 @@ pub(crate) fn build_impl(
 
     // Only inline impl if the implemented trait is
     // reachable in rustdoc generated documentation
-    if !did.is_local() {
-        if let Some(traitref) = associated_trait {
-            let did = traitref.def_id;
-            if !cx.cache.effective_visibilities.is_directly_public(tcx, did) {
-                return;
-            }
+    if !did.is_local() && let Some(traitref) = associated_trait {
+        let did = traitref.def_id;
+        if !cx.cache.effective_visibilities.is_directly_public(tcx, did) {
+            return;
+        }
 
-            if let Some(stab) = tcx.lookup_stability(did) {
-                if stab.is_unstable() && stab.feature == sym::rustc_private {
-                    return;
-                }
-            }
+        if let Some(stab) = tcx.lookup_stability(did) &&
+            stab.is_unstable() &&
+            stab.feature == sym::rustc_private
+        {
+            return;
         }
     }
 
@@ -525,10 +524,8 @@ pub(crate) fn build_impl(
     }
 
     while let Some(ty) = stack.pop() {
-        if let Some(did) = ty.def_id(&cx.cache) {
-            if tcx.is_doc_hidden(did) {
-                return;
-            }
+        if let Some(did) = ty.def_id(&cx.cache) && tcx.is_doc_hidden(did) {
+            return;
         }
         if let Some(generics) = ty.generics() {
             stack.extend(generics);

src/librustdoc/clean/mod.rs

@@ -787,43 +787,43 @@ fn clean_ty_generics<'tcx>(
                 None
             })();
 
-            if let Some(param_idx) = param_idx {
-                if let Some(b) = impl_trait.get_mut(&param_idx.into()) {
-                    let p: WherePredicate = clean_predicate(*p, cx)?;
+            if let Some(param_idx) = param_idx
+                && let Some(b) = impl_trait.get_mut(&param_idx.into())
+            {
+                let p: WherePredicate = clean_predicate(*p, cx)?;
+
+                b.extend(
+                    p.get_bounds()
+                        .into_iter()
+                        .flatten()
+                        .cloned()
+                        .filter(|b| !b.is_sized_bound(cx)),
+                );
 
-                    b.extend(
-                        p.get_bounds()
+                let proj = projection.map(|p| {
+                    (
+                        clean_projection(p.map_bound(|p| p.projection_ty), cx, None),
+                        p.map_bound(|p| p.term),
+                    )
+                });
+                if let Some(((_, trait_did, name), rhs)) = proj
+                    .as_ref()
+                    .and_then(|(lhs, rhs): &(Type, _)| Some((lhs.projection()?, rhs)))
+                {
+                    // FIXME(...): Remove this unwrap()
+                    impl_trait_proj.entry(param_idx).or_default().push((
+                        trait_did,
+                        name,
+                        rhs.map_bound(|rhs| rhs.ty().unwrap()),
+                        p.get_bound_params()
                             .into_iter()
                             .flatten()
-                            .cloned()
-                            .filter(|b| !b.is_sized_bound(cx)),
-                    );
-
-                    let proj = projection.map(|p| {
-                        (
-                            clean_projection(p.map_bound(|p| p.projection_ty), cx, None),
-                            p.map_bound(|p| p.term),
-                        )
-                    });
-                    if let Some(((_, trait_did, name), rhs)) = proj
-                        .as_ref()
-                        .and_then(|(lhs, rhs): &(Type, _)| Some((lhs.projection()?, rhs)))
-                    {
-                        // FIXME(...): Remove this unwrap()
-                        impl_trait_proj.entry(param_idx).or_default().push((
-                            trait_did,
-                            name,
-                            rhs.map_bound(|rhs| rhs.ty().unwrap()),
-                            p.get_bound_params()
-                                .into_iter()
-                                .flatten()
-                                .map(|param| GenericParamDef::lifetime(param.0))
-                                .collect(),
-                        ));
-                    }
-
-                    return None;
+                            .map(|param| GenericParamDef::lifetime(param.0))
+                            .collect(),
+                    ));
                 }
+
+                return None;
             }
 
             Some(p)
@@ -886,7 +886,7 @@ fn clean_ty_generics<'tcx>(
     // `?Sized` bound for each one we didn't find to be `Sized`.
     for tp in &stripped_params {
         if let types::GenericParamDefKind::Type { .. } = tp.kind
-        && !sized_params.contains(&tp.name)
+            && !sized_params.contains(&tp.name)
         {
             where_predicates.push(WherePredicate::BoundPredicate {
                 ty: Type::Generic(tp.name),
@@ -1461,10 +1461,10 @@ fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type
             // Try to normalize `<X as Y>::T` to a type
             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
             // `hir_to_ty` can return projection types with escaping vars for GATs, e.g. `<() as Trait>::Gat<'_>`
-            if !ty.has_escaping_bound_vars() {
-                if let Some(normalized_value) = normalize(cx, ty::Binder::dummy(ty)) {
-                    return clean_middle_ty(normalized_value, cx, None);
-                }
+            if !ty.has_escaping_bound_vars()
+                && let Some(normalized_value) = normalize(cx, ty::Binder::dummy(ty))
+            {
+                return clean_middle_ty(normalized_value, cx, None);
             }
 
             let trait_segments = &p.segments[..p.segments.len() - 1];
@@ -1878,11 +1878,9 @@ fn clean_middle_opaque_bounds<'tcx>(
                 _ => return None,
             };
 
-            if let Some(sized) = cx.tcx.lang_items().sized_trait() {
-                if trait_ref.def_id() == sized {
-                    has_sized = true;
-                    return None;
-                }
+            if let Some(sized) = cx.tcx.lang_items().sized_trait() && trait_ref.def_id() == sized {
+                has_sized = true;
+                return None;
             }
 
             let bindings: ThinVec<_> = bounds
@@ -2392,17 +2390,15 @@ fn clean_use_statement_inner<'tcx>(
     let is_visible_from_parent_mod =
         visibility.is_accessible_from(parent_mod, cx.tcx) && !current_mod.is_top_level_module();
 
-    if pub_underscore {
-        if let Some(ref inline) = inline_attr {
-            rustc_errors::struct_span_err!(
-                cx.tcx.sess,
-                inline.span(),
-                E0780,
-                "anonymous imports cannot be inlined"
-            )
-            .span_label(import.span, "anonymous import")
-            .emit();
-        }
+    if pub_underscore && let Some(ref inline) = inline_attr {
+        rustc_errors::struct_span_err!(
+            cx.tcx.sess,
+            inline.span(),
+            E0780,
+            "anonymous imports cannot be inlined"
+        )
+        .span_label(import.span, "anonymous import")
+        .emit();
     }
 
     // We consider inlining the documentation of `pub use` statements, but we
@@ -2438,14 +2434,13 @@ fn clean_use_statement_inner<'tcx>(
         }
         Import::new_glob(resolve_use_source(cx, path), true)
     } else {
-        if inline_attr.is_none() {
-            if let Res::Def(DefKind::Mod, did) = path.res {
-                if !did.is_local() && did.is_crate_root() {
-                    // if we're `pub use`ing an extern crate root, don't inline it unless we
-                    // were specifically asked for it
-                    denied = true;
-                }
-            }
+        if inline_attr.is_none()
+            && let Res::Def(DefKind::Mod, did) = path.res
+            && !did.is_local() && did.is_crate_root()
+        {
+            // if we're `pub use`ing an extern crate root, don't inline it unless we
+            // were specifically asked for it
+            denied = true;
         }
         if !denied {
             let mut visited = DefIdSet::default();

src/librustdoc/clean/types.rs

@@ -182,10 +182,8 @@ impl ExternalCrate {
             return Local;
         }
 
-        if extern_url_takes_precedence {
-            if let Some(url) = extern_url {
-                return to_remote(url);
-            }
+        if extern_url_takes_precedence && let Some(url) = extern_url {
+            return to_remote(url);
         }
 
         // Failing that, see if there's an attribute specifying where to find this
@@ -1172,10 +1170,10 @@ impl GenericBound {
 
     pub(crate) fn is_sized_bound(&self, cx: &DocContext<'_>) -> bool {
         use rustc_hir::TraitBoundModifier as TBM;
-        if let GenericBound::TraitBound(PolyTrait { ref trait_, .. }, TBM::None) = *self {
-            if Some(trait_.def_id()) == cx.tcx.lang_items().sized_trait() {
-                return true;
-            }
+        if let GenericBound::TraitBound(PolyTrait { ref trait_, .. }, TBM::None) = *self &&
+            Some(trait_.def_id()) == cx.tcx.lang_items().sized_trait()
+        {
+            return true;
         }
         false
     }

src/librustdoc/clean/utils.rs

@@ -345,10 +345,10 @@ pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
             return true;
         }
 
-        if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind {
-            if let hir::ExprKind::Lit(_) = &expr.kind {
-                return true;
-            }
+        if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind &&
+            let hir::ExprKind::Lit(_) = &expr.kind
+        {
+            return true;
         }
     }
 

src/librustdoc/doctest.rs

@@ -229,11 +229,11 @@ fn scrape_test_config(attrs: &[ast::Attribute]) -> GlobalTestOptions {
         if attr.has_name(sym::no_crate_inject) {
             opts.no_crate_inject = true;
         }
-        if attr.has_name(sym::attr) {
-            if let Some(l) = attr.meta_item_list() {
-                for item in l {
-                    opts.attrs.push(pprust::meta_list_item_to_string(item));
-                }
+        if attr.has_name(sym::attr)
+            && let Some(l) = attr.meta_item_list()
+        {
+            for item in l {
+                opts.attrs.push(pprust::meta_list_item_to_string(item));
             }
         }
     }
@@ -594,31 +594,28 @@ pub(crate) fn make_test(
             loop {
                 match parser.parse_item(ForceCollect::No) {
                     Ok(Some(item)) => {
-                        if !found_main {
-                            if let ast::ItemKind::Fn(..) = item.kind {
-                                if item.ident.name == sym::main {
-                                    found_main = true;
-                                }
-                            }
+                        if !found_main &&
+                            let ast::ItemKind::Fn(..) = item.kind &&
+                            item.ident.name == sym::main
+                        {
+                            found_main = true;
                         }
 
-                        if !found_extern_crate {
-                            if let ast::ItemKind::ExternCrate(original) = item.kind {
-                                // This code will never be reached if `crate_name` is none because
-                                // `found_extern_crate` is initialized to `true` if it is none.
-                                let crate_name = crate_name.unwrap();
+                        if !found_extern_crate &&
+                            let ast::ItemKind::ExternCrate(original) = item.kind
+                        {
+                            // This code will never be reached if `crate_name` is none because
+                            // `found_extern_crate` is initialized to `true` if it is none.
+                            let crate_name = crate_name.unwrap();
 
-                                match original {
-                                    Some(name) => found_extern_crate = name.as_str() == crate_name,
-                                    None => found_extern_crate = item.ident.as_str() == crate_name,
-                                }
+                            match original {
+                                Some(name) => found_extern_crate = name.as_str() == crate_name,
+                                None => found_extern_crate = item.ident.as_str() == crate_name,
                             }
                         }
 
-                        if !found_macro {
-                            if let ast::ItemKind::MacCall(..) = item.kind {
-                                found_macro = true;
-                            }
+                        if !found_macro && let ast::ItemKind::MacCall(..) = item.kind {
+                            found_macro = true;
                         }
 
                         if found_main && found_extern_crate {
@@ -972,14 +969,12 @@ impl Collector {
     fn get_filename(&self) -> FileName {
         if let Some(ref source_map) = self.source_map {
             let filename = source_map.span_to_filename(self.position);
-            if let FileName::Real(ref filename) = filename {
-                if let Ok(cur_dir) = env::current_dir() {
-                    if let Some(local_path) = filename.local_path() {
-                        if let Ok(path) = local_path.strip_prefix(&cur_dir) {
-                            return path.to_owned().into();
-                        }
-                    }
-                }
+            if let FileName::Real(ref filename) = filename &&
+                let Ok(cur_dir) = env::current_dir() &&
+                let Some(local_path) = filename.local_path() &&
+                let Ok(path) = local_path.strip_prefix(&cur_dir)
+            {
+                return path.to_owned().into();
             }
             filename
         } else if let Some(ref filename) = self.filename {

src/librustdoc/formats/cache.rs

@@ -229,16 +229,15 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
         }
 
         // Collect all the implementors of traits.
-        if let clean::ImplItem(ref i) = *item.kind {
-            if let Some(trait_) = &i.trait_ {
-                if !i.kind.is_blanket() {
-                    self.cache
-                        .implementors
-                        .entry(trait_.def_id())
-                        .or_default()
-                        .push(Impl { impl_item: item.clone() });
-                }
-            }
+        if let clean::ImplItem(ref i) = *item.kind &&
+            let Some(trait_) = &i.trait_ &&
+            !i.kind.is_blanket()
+        {
+            self.cache
+                .implementors
+                .entry(trait_.def_id())
+                .or_default()
+                .push(Impl { impl_item: item.clone() });
         }
 
         // Index this method for searching later on.

src/librustdoc/html/format.rs

@@ -709,11 +709,9 @@ pub(crate) fn href_with_root_path(
             }
         }
     };
-    if !is_remote {
-        if let Some(root_path) = root_path {
-            let root = root_path.trim_end_matches('/');
-            url_parts.push_front(root);
-        }
+    if !is_remote && let Some(root_path) = root_path {
+        let root = root_path.trim_end_matches('/');
+        url_parts.push_front(root);
     }
     debug!(?url_parts);
     match shortty {