use outermost invocation span for doctest names

Fixes #70090.

src/librustdoc/test.rs

@@ -944,7 +944,12 @@ impl<'a, 'hir, 'tcx> HirCollector<'a, 'hir, 'tcx> {
         // The collapse-docs pass won't combine sugared/raw doc attributes, or included files with
         // anything else, this will combine them for us.
         if let Some(doc) = attrs.collapsed_doc_value() {
-            self.collector.set_position(attrs.span.unwrap_or(DUMMY_SP));
+            // Use the outermost invocation, so that doctest names come from where the docs were written.
+            let span = attrs
+                .span
+                .map(|span| span.ctxt().outer_expn().expansion_cause().unwrap_or(span))
+                .unwrap_or(DUMMY_SP);
+            self.collector.set_position(span);
             markdown::find_testable_code(
                 &doc,
                 self.collector,

src/test/rustdoc-ui/auxiliary/extern_macros.rs

@@ -0,0 +1,7 @@
+#[macro_export]
+macro_rules! attrs_on_struct {
+    ( $( #[$attr:meta] )* ) => {
+        $( #[$attr] )*
+        pub struct ExpandedStruct;
+    }
+}

src/test/rustdoc-ui/doctest-output.rs

@@ -1,3 +1,5 @@
+// edition:2018
+// aux-build:extern_macros.rs
 // compile-flags:--test --test-args=--test-threads=1
 // normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
 // check-pass
@@ -6,10 +8,20 @@
 //! assert_eq!(1 + 1, 2);
 //! ```
 
+extern crate extern_macros as macros;
+
+use macros::attrs_on_struct;
+
 pub mod foo {
 
     /// ```
     /// assert_eq!(1 + 1, 2);
     /// ```
     pub fn bar() {}
 }
+
+attrs_on_struct! {
+    /// ```
+    /// assert!(true);
+    /// ```
+}

src/test/rustdoc-ui/doctest-output.stdout

@@ -1,7 +1,8 @@
 
-running 2 tests
-test $DIR/doctest-output.rs - (line 5) ... ok
-test $DIR/doctest-output.rs - foo::bar (line 11) ... ok
+running 3 tests
+test $DIR/doctest-output.rs - (line 7) ... ok
+test $DIR/doctest-output.rs - ExpandedStruct (line 23) ... ok
+test $DIR/doctest-output.rs - foo::bar (line 17) ... ok
 
-test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
+test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out