From 1862fcb1df05b116443ad3b27028616a180ffadb Mon Sep 17 00:00:00 2001 From: Michael Howell Date: Tue, 30 May 2023 12:07:03 -0700 Subject: [PATCH] rustdoc: simplify `clean` by removing `FnRetTy` The default fn ret ty is always unit. Just use that. Looking back at the time when `FnRetTy` (then called `FunctionRetTy`) was first added to rustdoc, it seems to originally be there because `-> !` was a special form: the never type didn't exist back then. https://github.com/rust-lang/rust/commit/eb01b17b06eb35542bb80ff7456043b0ed5572ba#diff-384affc1b4190940f114f3fcebbf969e7e18657a71ef9001da6b223a036687d9L921-L924 --- src/librustdoc/clean/mod.rs | 9 ++--- src/librustdoc/clean/types.rs | 44 ++++++++-------------- src/librustdoc/html/format.rs | 39 +++++++++---------- src/librustdoc/html/render/mod.rs | 7 +++- src/librustdoc/html/render/print_item.rs | 3 +- src/librustdoc/html/render/search_index.rs | 23 +++-------- src/librustdoc/json/conversions.rs | 5 +-- 7 files changed, 49 insertions(+), 81 deletions(-) diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs index 03adc19e359c1..5fd867189fd71 100644 --- a/src/librustdoc/clean/mod.rs +++ b/src/librustdoc/clean/mod.rs @@ -1111,8 +1111,8 @@ fn clean_fn_decl_with_args<'tcx>( args: Arguments, ) -> FnDecl { let output = match decl.output { - hir::FnRetTy::Return(typ) => Return(clean_ty(typ, cx)), - hir::FnRetTy::DefaultReturn(..) => DefaultReturn, + hir::FnRetTy::Return(typ) => clean_ty(typ, cx), + hir::FnRetTy::DefaultReturn(..) => Type::Tuple(Vec::new()), }; FnDecl { inputs: args, output, c_variadic: decl.c_variadic } } @@ -1126,10 +1126,7 @@ fn clean_fn_decl_from_did_and_sig<'tcx>( // We assume all empty tuples are default return type. This theoretically can discard `-> ()`, // but shouldn't change any code meaning. - let output = match clean_middle_ty(sig.output(), cx, None) { - Type::Tuple(inner) if inner.is_empty() => DefaultReturn, - ty => Return(ty), - }; + let output = clean_middle_ty(sig.output(), cx, None); FnDecl { output, diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs index e9ccea2cf270f..1999a6b671d3a 100644 --- a/src/librustdoc/clean/types.rs +++ b/src/librustdoc/clean/types.rs @@ -42,7 +42,6 @@ use crate::formats::item_type::ItemType; use crate::html::render::Context; use crate::passes::collect_intra_doc_links::UrlFragment; -pub(crate) use self::FnRetTy::*; pub(crate) use self::ItemKind::*; pub(crate) use self::SelfTy::*; pub(crate) use self::Type::{ @@ -1353,7 +1352,7 @@ pub(crate) struct Function { #[derive(Clone, PartialEq, Eq, Debug, Hash)] pub(crate) struct FnDecl { pub(crate) inputs: Arguments, - pub(crate) output: FnRetTy, + pub(crate) output: Type, pub(crate) c_variadic: bool, } @@ -1371,18 +1370,16 @@ impl FnDecl { /// /// This function will panic if the return type does not match the expected sugaring for async /// functions. - pub(crate) fn sugared_async_return_type(&self) -> FnRetTy { - match &self.output { - FnRetTy::Return(Type::ImplTrait(bounds)) => match &bounds[0] { - GenericBound::TraitBound(PolyTrait { trait_, .. }, ..) => { - let bindings = trait_.bindings().unwrap(); - let ret_ty = bindings[0].term(); - let ty = ret_ty.ty().expect("Unexpected constant return term"); - FnRetTy::Return(ty.clone()) - } - _ => panic!("unexpected desugaring of async function"), - }, - _ => panic!("unexpected desugaring of async function"), + pub(crate) fn sugared_async_return_type(&self) -> Type { + if let Type::ImplTrait(v) = &self.output && + let [GenericBound::TraitBound(PolyTrait { trait_, .. }, _ )] = &v[..] + { + let bindings = trait_.bindings().unwrap(); + let ret_ty = bindings[0].term(); + let ty = ret_ty.ty().expect("Unexpected constant return term"); + ty.clone() + } else { + panic!("unexpected desugaring of async function") } } } @@ -1425,21 +1422,6 @@ impl Argument { } } -#[derive(Clone, PartialEq, Eq, Debug, Hash)] -pub(crate) enum FnRetTy { - Return(Type), - DefaultReturn, -} - -impl FnRetTy { - pub(crate) fn as_return(&self) -> Option<&Type> { - match self { - Return(ret) => Some(ret), - DefaultReturn => None, - } - } -} - #[derive(Clone, Debug)] pub(crate) struct Trait { pub(crate) def_id: DefId, @@ -1641,6 +1623,10 @@ impl Type { matches!(self, Type::ImplTrait(_)) } + pub(crate) fn is_unit(&self) -> bool { + matches!(self, Type::Tuple(v) if v.is_empty()) + } + pub(crate) fn projection(&self) -> Option<(&Type, DefId, PathSegment)> { if let QPath(box QPathData { self_type, trait_, assoc, .. }) = self { Some((self_type, trait_.as_ref()?.def_id(), assoc.clone())) diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs index d963d6092c48f..f26d74629dd94 100644 --- a/src/librustdoc/html/format.rs +++ b/src/librustdoc/html/format.rs @@ -1257,9 +1257,9 @@ impl clean::Impl { }; primitive_link_fragment(f, PrimitiveType::Tuple, &format!("fn ({name}₁, {name}₂, …, {name}ₙ{ellipsis})"), "#trait-implementations-1", cx)?; // Write output. - if let clean::FnRetTy::Return(ty) = &bare_fn.decl.output { + if !bare_fn.decl.output.is_unit() { write!(f, " -> ")?; - fmt_type(ty, f, use_absolute, cx)?; + fmt_type(&bare_fn.decl.output, f, use_absolute, cx)?; } } else if let Some(ty) = self.kind.as_blanket_ty() { fmt_type(ty, f, use_absolute, cx)?; @@ -1296,22 +1296,6 @@ impl clean::Arguments { } } -impl clean::FnRetTy { - pub(crate) fn print<'a, 'tcx: 'a>( - &'a self, - cx: &'a Context<'tcx>, - ) -> impl fmt::Display + 'a + Captures<'tcx> { - display_fn(move |f| match self { - clean::Return(clean::Tuple(tys)) if tys.is_empty() => Ok(()), - clean::Return(ty) if f.alternate() => { - write!(f, " -> {:#}", ty.print(cx)) - } - clean::Return(ty) => write!(f, " -> {}", ty.print(cx)), - clean::DefaultReturn => Ok(()), - }) - } -} - impl clean::BareFunctionDecl { fn print_hrtb_with_space<'a, 'tcx: 'a>( &'a self, @@ -1366,7 +1350,7 @@ impl clean::FnDecl { "({args:#}{ellipsis}){arrow:#}", args = self.inputs.print(cx), ellipsis = ellipsis, - arrow = self.output.print(cx) + arrow = self.print_output(cx) ) } else { write!( @@ -1374,7 +1358,7 @@ impl clean::FnDecl { "({args}{ellipsis}){arrow}", args = self.inputs.print(cx), ellipsis = ellipsis, - arrow = self.output.print(cx) + arrow = self.print_output(cx) ) } }) @@ -1464,9 +1448,22 @@ impl clean::FnDecl { Some(n) => write!(f, "\n{})", Indent(n))?, }; - fmt::Display::fmt(&self.output.print(cx), f)?; + fmt::Display::fmt(&self.print_output(cx), f)?; Ok(()) } + + pub(crate) fn print_output<'a, 'tcx: 'a>( + &'a self, + cx: &'a Context<'tcx>, + ) -> impl fmt::Display + 'a + Captures<'tcx> { + display_fn(move |f| match &self.output { + clean::Tuple(tys) if tys.is_empty() => Ok(()), + ty if f.alternate() => { + write!(f, " -> {:#}", ty.print(cx)) + } + ty => write!(f, " -> {}", ty.print(cx)), + }) + } } pub(crate) fn visibility_print_with_space<'a, 'tcx: 'a>( diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs index 42e27d35a94b1..a5223bd6309d7 100644 --- a/src/librustdoc/html/render/mod.rs +++ b/src/librustdoc/html/render/mod.rs @@ -844,7 +844,7 @@ fn assoc_method( + name.as_str().len() + generics_len; - let notable_traits = d.output.as_return().and_then(|output| notable_traits_button(output, cx)); + let notable_traits = notable_traits_button(&d.output, cx); let (indent, indent_str, end_newline) = if parent == ItemType::Trait { header_len += 4; @@ -1282,6 +1282,11 @@ fn should_render_item(item: &clean::Item, deref_mut_: bool, tcx: TyCtxt<'_>) -> pub(crate) fn notable_traits_button(ty: &clean::Type, cx: &mut Context<'_>) -> Option { let mut has_notable_trait = false; + if ty.is_unit() { + // Very common fast path. + return None; + } + let did = ty.def_id(cx.cache())?; // Box has pass-through impls for Read, Write, Iterator, and Future when the diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs index d2dc47af7ac4f..1da266e41a599 100644 --- a/src/librustdoc/html/render/print_item.rs +++ b/src/librustdoc/html/render/print_item.rs @@ -587,8 +587,7 @@ fn item_function(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, f: &cle + name.as_str().len() + generics_len; - let notable_traits = - f.decl.output.as_return().and_then(|output| notable_traits_button(output, cx)); + let notable_traits = notable_traits_button(&f.decl.output, cx); wrap_item(w, |w| { w.reserve(header_len); diff --git a/src/librustdoc/html/render/search_index.rs b/src/librustdoc/html/render/search_index.rs index 846299f02e33c..f34be120d292b 100644 --- a/src/librustdoc/html/render/search_index.rs +++ b/src/librustdoc/html/render/search_index.rs @@ -7,7 +7,7 @@ use rustc_span::symbol::Symbol; use serde::ser::{Serialize, SerializeStruct, Serializer}; use crate::clean; -use crate::clean::types::{FnRetTy, Function, Generics, ItemId, Type, WherePredicate}; +use crate::clean::types::{Function, Generics, ItemId, Type, WherePredicate}; use crate::formats::cache::{Cache, OrphanImplItem}; use crate::formats::item_type::ItemType; use crate::html::format::join_with_double_colon; @@ -656,22 +656,9 @@ fn get_fn_inputs_and_outputs<'tcx>( } let mut ret_types = Vec::new(); - match decl.output { - FnRetTy::Return(ref return_type) => { - add_generics_and_bounds_as_types( - self_, - generics, - return_type, - tcx, - 0, - &mut ret_types, - cache, - ); - if ret_types.is_empty() { - ret_types.push(get_index_type(return_type, vec![])); - } - } - _ => {} - }; + add_generics_and_bounds_as_types(self_, generics, &decl.output, tcx, 0, &mut ret_types, cache); + if ret_types.is_empty() { + ret_types.push(get_index_type(&decl.output, vec![])); + } (all_types, ret_types) } diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs index 935bb721f1803..91cd55b1113ab 100644 --- a/src/librustdoc/json/conversions.rs +++ b/src/librustdoc/json/conversions.rs @@ -624,10 +624,7 @@ impl FromWithTcx for FnDecl { .into_iter() .map(|arg| (arg.name.to_string(), arg.type_.into_tcx(tcx))) .collect(), - output: match output { - clean::FnRetTy::Return(t) => Some(t.into_tcx(tcx)), - clean::FnRetTy::DefaultReturn => None, - }, + output: if output.is_unit() { None } else { Some(output.into_tcx(tcx)) }, c_variadic, } }