Change DocFragments from enum variant fields to structs with a nested enum

This makes the code a lot easier to work with. It also makes it easier
to add new fields without updating each variant and `match`
individually.

- Name the `Kind` variant after `DocFragmentKind` from `collapse_docs`
- Remove unneeded impls

src/librustdoc/clean/types.rs

@@ -370,32 +370,22 @@ impl<I: IntoIterator<Item = ast::NestedMetaItem>> NestedAttributesExt for I {
 /// information can be given when a doctest fails. Sugared doc comments and "raw" doc comments are
 /// kept separate because of issue #42760.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
-pub enum DocFragment {
+pub struct DocFragment {
-    /// A doc fragment created from a `///` or `//!` doc comment.
+    pub line: usize,
-    SugaredDoc(usize, rustc_span::Span, String),
+    pub span: rustc_span::Span,
-    /// A doc fragment created from a "raw" `#[doc=""]` attribute.
+    pub doc: String,
-    RawDoc(usize, rustc_span::Span, String),
+    pub kind: DocFragmentKind,
-    /// A doc fragment created from a `#[doc(include="filename")]` attribute. Contains both the
-    /// given filename and the file contents.
-    Include(usize, rustc_span::Span, String, String),
 }
 
-impl DocFragment {
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
-    pub fn as_str(&self) -> &str {
+pub enum DocFragmentKind {
-        match *self {
+    /// A doc fragment created from a `///` or `//!` doc comment.
-            DocFragment::SugaredDoc(_, _, ref s) => &s[..],
+    SugaredDoc,
-            DocFragment::RawDoc(_, _, ref s) => &s[..],
+    /// A doc fragment created from a "raw" `#[doc=""]` attribute.
-            DocFragment::Include(_, _, _, ref s) => &s[..],
+    RawDoc,
-        }
+    /// A doc fragment created from a `#[doc(include="filename")]` attribute. Contains both the
-    }
+    /// given filename and the file contents.
-
+    Include { filename: String },
-    pub fn span(&self) -> rustc_span::Span {
-        match *self {
-            DocFragment::SugaredDoc(_, span, _)
-            | DocFragment::RawDoc(_, span, _)
-            | DocFragment::Include(_, span, _, _) => span,
-        }
-    }
 }
 
 impl<'a> FromIterator<&'a DocFragment> for String {
@@ -407,12 +397,7 @@ impl<'a> FromIterator<&'a DocFragment> for String {
             if !acc.is_empty() {
                 acc.push('\n');
             }
-            match *frag {
+            acc.push_str(&frag.doc);
-                DocFragment::SugaredDoc(_, _, ref docs)
-                | DocFragment::RawDoc(_, _, ref docs)
-                | DocFragment::Include(_, _, _, ref docs) => acc.push_str(docs),
-            }
-
             acc
         })
     }
@@ -547,15 +532,15 @@ impl Attributes {
             .filter_map(|attr| {
                 if let Some(value) = attr.doc_str() {
                     let value = beautify_doc_string(value);
-                    let mk_fragment: fn(_, _, _) -> _ = if attr.is_doc_comment() {
+                    let kind = if attr.is_doc_comment() {
-                        DocFragment::SugaredDoc
+                        DocFragmentKind::SugaredDoc
                     } else {
-                        DocFragment::RawDoc
+                        DocFragmentKind::RawDoc
                     };
 
                     let line = doc_line;
                     doc_line += value.lines().count();
-                    doc_strings.push(mk_fragment(line, attr.span, value));
+                    doc_strings.push(DocFragment { line, span: attr.span, doc: value, kind });
 
                     if sp.is_none() {
                         sp = Some(attr.span);
@@ -575,9 +560,12 @@ impl Attributes {
                             {
                                 let line = doc_line;
                                 doc_line += contents.lines().count();
-                                doc_strings.push(DocFragment::Include(
+                                doc_strings.push(DocFragment {
-                                    line, attr.span, filename, contents,
+                                    line,
-                                ));
+                                    span: attr.span,
+                                    doc: contents,
+                                    kind: DocFragmentKind::Include { filename },
+                                });
                             }
                         }
                     }
@@ -621,7 +609,7 @@ impl Attributes {
     /// Finds the `doc` attribute as a NameValue and returns the corresponding
     /// value found.
     pub fn doc_value(&self) -> Option<&str> {
-        self.doc_strings.first().map(|s| s.as_str())
+        self.doc_strings.first().map(|s| s.doc.as_str())
     }
 
     /// Finds all `doc` attributes as NameValues and returns their corresponding values, joined

src/librustdoc/passes/calculate_doc_coverage.rs

@@ -232,7 +232,12 @@ impl fold::DocFolder for CoverageCalculator {
                 let mut tests = Tests { found_tests: 0 };
 
                 find_testable_code(
-                    &i.attrs.doc_strings.iter().map(|d| d.as_str()).collect::<Vec<_>>().join("\n"),
+                    &i.attrs
+                        .doc_strings
+                        .iter()
+                        .map(|d| d.doc.as_str())
+                        .collect::<Vec<_>>()
+                        .join("\n"),
                     &mut tests,
                     ErrorCodes::No,
                     false,

src/librustdoc/passes/collapse_docs.rs

@@ -1,4 +1,4 @@
-use crate::clean::{self, DocFragment, Item};
+use crate::clean::{self, DocFragment, DocFragmentKind, Item};
 use crate::core::DocContext;
 use crate::fold;
 use crate::fold::DocFolder;
@@ -12,23 +12,6 @@ pub const COLLAPSE_DOCS: Pass = Pass {
     description: "concatenates all document attributes into one document attribute",
 };
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-enum DocFragmentKind {
-    Sugared,
-    Raw,
-    Include,
-}
-
-impl DocFragment {
-    fn kind(&self) -> DocFragmentKind {
-        match *self {
-            DocFragment::SugaredDoc(..) => DocFragmentKind::Sugared,
-            DocFragment::RawDoc(..) => DocFragmentKind::Raw,
-            DocFragment::Include(..) => DocFragmentKind::Include,
-        }
-    }
-}
-
 pub fn collapse_docs(krate: clean::Crate, _: &DocContext<'_>) -> clean::Crate {
     let mut krate = Collapser.fold_crate(krate);
     krate.collapsed = true;
@@ -50,30 +33,22 @@ fn collapse(doc_strings: &mut Vec<DocFragment>) {
 
     for frag in take(doc_strings) {
         if let Some(mut curr_frag) = last_frag.take() {
-            let curr_kind = curr_frag.kind();
+            let curr_kind = &curr_frag.kind;
-            let new_kind = frag.kind();
+            let new_kind = &frag.kind;
 
-            if curr_kind == DocFragmentKind::Include || curr_kind != new_kind {
+            if matches!(*curr_kind, DocFragmentKind::Include { .. }) || curr_kind != new_kind {
-                match curr_frag {
+                if *curr_kind == DocFragmentKind::SugaredDoc
-                    DocFragment::SugaredDoc(_, _, ref mut doc_string)
+                    || *curr_kind == DocFragmentKind::RawDoc
-                    | DocFragment::RawDoc(_, _, ref mut doc_string) => {
+                {
                     // add a newline for extra padding between segments
-                        doc_string.push('\n');
+                    curr_frag.doc.push('\n');
-                    }
-                    _ => {}
                 }
                 docs.push(curr_frag);
                 last_frag = Some(frag);
             } else {
-                match curr_frag {
+                curr_frag.doc.push('\n');
-                    DocFragment::SugaredDoc(_, ref mut span, ref mut doc_string)
+                curr_frag.doc.push_str(&frag.doc);
-                    | DocFragment::RawDoc(_, ref mut span, ref mut doc_string) => {
+                curr_frag.span = curr_frag.span.to(frag.span);
-                        doc_string.push('\n');
-                        doc_string.push_str(frag.as_str());
-                        *span = span.to(frag.span());
-                    }
-                    _ => unreachable!(),
-                }
                 last_frag = Some(curr_frag);
             }
         } else {

src/librustdoc/passes/mod.rs

@@ -8,7 +8,7 @@ use std::mem;
 use std::ops::Range;
 
 use self::Condition::*;
-use crate::clean::{self, GetDefId, Item};
+use crate::clean::{self, DocFragmentKind, GetDefId, Item};
 use crate::core::DocContext;
 use crate::fold::{DocFolder, StripItem};
 
@@ -314,11 +314,11 @@ crate fn span_of_attrs(attrs: &clean::Attributes) -> Option<Span> {
     if attrs.doc_strings.is_empty() {
         return None;
     }
-    let start = attrs.doc_strings[0].span();
+    let start = attrs.doc_strings[0].span;
     if start == DUMMY_SP {
         return None;
     }
-    let end = attrs.doc_strings.last().expect("no doc strings provided").span();
+    let end = attrs.doc_strings.last().expect("no doc strings provided").span;
     Some(start.to(end))
 }
 
@@ -333,10 +333,8 @@ crate fn source_span_for_markdown_range(
     md_range: &Range<usize>,
     attrs: &clean::Attributes,
 ) -> Option<Span> {
-    let is_all_sugared_doc = attrs.doc_strings.iter().all(|frag| match frag {
+    let is_all_sugared_doc =
-        clean::DocFragment::SugaredDoc(..) => true,
+        attrs.doc_strings.iter().all(|frag| frag.kind == DocFragmentKind::SugaredDoc);
-        _ => false,
-    });
 
     if !is_all_sugared_doc {
         return None;

src/librustdoc/passes/unindent_comments.rs

@@ -36,13 +36,7 @@ impl clean::Attributes {
 
 fn unindent_fragments(docs: &mut Vec<DocFragment>) {
     for fragment in docs {
-        match *fragment {
+        fragment.doc = unindent(&fragment.doc);
-            DocFragment::SugaredDoc(_, _, ref mut doc_string)
-            | DocFragment::RawDoc(_, _, ref mut doc_string)
-            | DocFragment::Include(_, _, _, ref mut doc_string) => {
-                *doc_string = unindent(doc_string)
-            }
-        }
     }
 }