Rollup merge of #78908 - liketechnik:fix_macro_expand_src_link, r=jyn514

(rustdoc) [src] link for types defined by macros shows invocation, not defintion

Previously the [src] link on types defined by a macro pointed to the macro definition.

This pr makes the Clean-Implementation for Spans aware of macro defined types, so that the link points to the invocation instead.

I'm not totally sure if it's okay to add the 'macro awareness' in the Clean-Implementation, because it erases that knowledge for all following code. Maybe it would be more sensible to add the check only for the link generation at https://github.com/rust-lang/rust/blob/25f6938da459a57b43bdf16ed6bdad3225b2a3ce/src/librustdoc/html/render/mod.rs#L1619

Closes #39726.

Author: jonas-schievink

src/librustdoc/clean/mod.rs

@@ -1967,18 +1967,23 @@ impl Clean<Span> for rustc_span::Span {
             return Span::empty();
         }
 
+        // Get the macro invocation instead of the definition,
+        // in case the span is result of a macro expansion.
+        // (See rust-lang/rust#39726)
+        let span = self.source_callsite();
+
         let sm = cx.sess().source_map();
-        let filename = sm.span_to_filename(*self);
-        let lo = sm.lookup_char_pos(self.lo());
-        let hi = sm.lookup_char_pos(self.hi());
+        let filename = sm.span_to_filename(span);
+        let lo = sm.lookup_char_pos(span.lo());
+        let hi = sm.lookup_char_pos(span.hi());
         Span {
             filename,
             cnum: lo.file.cnum,
             loline: lo.line,
             locol: lo.col.to_usize(),
             hiline: hi.line,
             hicol: hi.col.to_usize(),
-            original: *self,
+            original: span,
         }
     }
 }

src/test/rustdoc/external-macro-src.rs

@@ -1,15 +1,12 @@
 // aux-build:external-macro-src.rs
-// ignore-tidy-linelength
 
 #![crate_name = "foo"]
 
 #[macro_use]
 extern crate external_macro_src;
 
-// @has foo/index.html '//a[@href="../src/foo/external-macro-src.rs.html#4-15"]' '[src]'
+// @has foo/index.html '//a[@href="../src/foo/external-macro-src.rs.html#3-12"]' '[src]'
 
 // @has foo/struct.Foo.html
-// @has - '//a[@href="https://example.com/src/external_macro_src/external-macro-src.rs.html#8"]' '[src]'
-// @has - '//a[@href="https://example.com/src/external_macro_src/external-macro-src.rs.html#9-13"]' '[src]'
-// @has - '//a[@href="https://example.com/src/external_macro_src/external-macro-src.rs.html#10-12"]' '[src]'
+// @has - '//a[@href="../src/foo/external-macro-src.rs.html#12"]' '[src]'
 make_foo!();

src/test/rustdoc/issue-26606.rs

@@ -7,5 +7,5 @@
 extern crate issue_26606_macro;
 
 // @has issue_26606/constant.FOO.html
-// @has - '//a/@href' '../src/issue_26606_macro/issue-26606-macro.rs.html#3'
+// @has - '//a[@href="../src/issue_26606/issue-26606.rs.html#11"]' '[src]'
 make_item!(FOO);

src/test/rustdoc/thread-local-src.rs

@@ -2,5 +2,5 @@
 
 // @has foo/index.html '//a[@href="../src/foo/thread-local-src.rs.html#1-6"]' '[src]'
 
-// @has foo/constant.FOO.html '//a/@href' 'https://doc.rust-lang.org/nightly/src/std/'
+// @has foo/constant.FOO.html '//a[@href="../src/foo/thread-local-src.rs.html#6"]' '[src]'
 thread_local!(pub static FOO: bool = false);