Do the hard part first

The only bit failing was the module, so change that before removing the
`span` field.

src/librustdoc/clean/inline.rs

@@ -487,7 +487,8 @@ fn build_module(
         }
     }
 
-    clean::Module { items }
+    let span = clean::Span::from_rustc_span(cx.tcx.def_span(did));
+    clean::Module { items, span }
 }
 
 crate fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {

src/librustdoc/clean/mod.rs

@@ -100,7 +100,7 @@ impl Clean<Item> for doctree::Module<'_> {
 
         // determine if we should display the inner contents or
         // the outer `mod` item for the source code.
-        let span = {
+        let span = Span::from_rustc_span({
             let sm = cx.sess().source_map();
             let outer = sm.lookup_char_pos(self.where_outer.lo());
             let inner = sm.lookup_char_pos(self.where_inner.lo());
@@ -111,11 +111,14 @@ impl Clean<Item> for doctree::Module<'_> {
                 // mod foo; (and a separate SourceFile for the contents)
                 self.where_inner
             }
-        };
+        });
 
-        let what_rustc_thinks =
-            Item::from_hir_id_and_parts(self.id, Some(self.name), ModuleItem(Module { items }), cx);
-        Item { span: span.clean(cx), ..what_rustc_thinks }
+        Item::from_hir_id_and_parts(
+            self.id,
+            Some(self.name),
+            ModuleItem(Module { items, span }),
+            cx,
+        )
     }
 }
 

src/librustdoc/clean/types.rs

@@ -232,7 +232,7 @@ impl fmt::Debug for Item {
         let def_id: &dyn fmt::Debug = if self.is_fake() { &"**FAKE**" } else { &self.def_id };
 
         fmt.debug_struct("Item")
-            .field("source", &self.span)
+            .field("source", &self.span())
             .field("name", &self.name)
             .field("attrs", &self.attrs)
             .field("kind", &self.kind)
@@ -255,8 +255,12 @@ impl Item {
         if self.is_fake() { None } else { tcx.lookup_deprecation(self.def_id) }
     }
 
+    crate fn span(&self) -> Span {
+        if let ItemKind::ModuleItem(Module { span, .. }) = &*self.kind { *span } else { self.span }
+    }
+
     crate fn attr_span(&self, _tcx: TyCtxt<'_>) -> rustc_span::Span {
-        crate::passes::span_of_attrs(&self.attrs).unwrap_or_else(|| self.span.inner())
+        crate::passes::span_of_attrs(&self.attrs).unwrap_or_else(|| self.span().inner())
     }
 
     /// Finds the `doc` attribute as a NameValue and returns the corresponding
@@ -609,6 +613,7 @@ impl ItemKind {
 #[derive(Clone, Debug)]
 crate struct Module {
     crate items: Vec<Item>,
+    crate span: Span,
 }
 
 crate struct ListAttributesIter<'a> {

src/librustdoc/fold.rs

@@ -80,7 +80,10 @@ crate trait DocFolder: Sized {
     }
 
     fn fold_mod(&mut self, m: Module) -> Module {
-        Module { items: m.items.into_iter().filter_map(|i| self.fold_item(i)).collect() }
+        Module {
+            span: m.span,
+            items: m.items.into_iter().filter_map(|i| self.fold_item(i)).collect(),
+        }
     }
 
     fn fold_crate(&mut self, mut c: Crate) -> Crate {

src/librustdoc/html/render/context.rs

@@ -281,15 +281,15 @@ impl<'tcx> Context<'tcx> {
     /// may happen, for example, with externally inlined items where the source
     /// of their crate documentation isn't known.
     pub(super) fn src_href(&self, item: &clean::Item) -> Option<String> {
-        if item.span.is_dummy() {
+        if item.span().is_dummy() {
             return None;
         }
         let mut root = self.root_path();
         let mut path = String::new();
-        let cnum = item.span.cnum(self.sess());
+        let cnum = item.span().cnum(self.sess());
 
         // We can safely ignore synthetic `SourceFile`s.
-        let file = match item.span.filename(self.sess()) {
+        let file = match item.span().filename(self.sess()) {
             FileName::Real(ref path) => path.local_path().to_path_buf(),
             _ => return None,
         };
@@ -323,8 +323,8 @@ impl<'tcx> Context<'tcx> {
             (&*symbol, &path)
         };
 
-        let loline = item.span.lo(self.sess()).line;
-        let hiline = item.span.hi(self.sess()).line;
+        let loline = item.span().lo(self.sess()).line;
+        let hiline = item.span().hi(self.sess()).line;
         let lines =
             if loline == hiline { loline.to_string() } else { format!("{}-{}", loline, hiline) };
         Some(format!(

src/librustdoc/html/render/print_item.rs

@@ -1013,7 +1013,7 @@ fn item_macro(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Mac
             Some("macro"),
             None,
             None,
-            it.span.inner().edition(),
+            it.span().inner().edition(),
         );
     });
     document(w, cx, it, None)

src/librustdoc/html/sources.rs

@@ -41,11 +41,11 @@ impl DocFolder for SourceCollector<'_, '_> {
         // then we need to render it out to the filesystem.
         if self.scx.include_sources
             // skip all synthetic "files"
-            && item.span.filename(self.sess()).is_real()
+            && item.span().filename(self.sess()).is_real()
             // skip non-local files
-            && item.span.cnum(self.sess()) == LOCAL_CRATE
+            && item.span().cnum(self.sess()) == LOCAL_CRATE
         {
-            let filename = item.span.filename(self.sess());
+            let filename = item.span().filename(self.sess());
             // If it turns out that we couldn't read this file, then we probably
             // can't read any of the files (generating html output from json or
             // something like that), so just don't include sources for the

src/librustdoc/json/conversions.rs

@@ -40,7 +40,8 @@ impl JsonRenderer<'_> {
             .iter()
             .map(rustc_ast_pretty::pprust::attribute_to_string)
             .collect();
-        let clean::Item { span, name, attrs: _, kind: _, visibility, def_id } = item;
+        let span = item.span();
+        let clean::Item { name, attrs: _, kind: _, span: _, visibility, def_id } = item;
         let inner = match *item.kind {
             clean::StrippedItem(_) => return None,
             _ => from_clean_item(item, self.tcx),

src/librustdoc/passes/calculate_doc_coverage.rs

@@ -211,7 +211,7 @@ impl<'a, 'b> fold::DocFolder for CoverageCalculator<'a, 'b> {
                     None,
                 );
 
-                let filename = i.span.filename(self.ctx.sess());
+                let filename = i.span().filename(self.ctx.sess());
                 let has_doc_example = tests.found_tests != 0;
                 let hir_id = self.ctx.tcx.hir().local_def_id_to_hir_id(i.def_id.expect_local());
                 let (level, source) = self.ctx.tcx.lint_level_at_node(MISSING_DOCS, hir_id);