rustdoc: handle macro expansions in types

Author: el-ev

src/librustdoc/html/macro_expansion.rs

@@ -1,5 +1,5 @@
-use rustc_ast::visit::{Visitor, walk_crate, walk_expr, walk_item, walk_pat, walk_stmt};
-use rustc_ast::{Crate, Expr, Item, Pat, PatKind, Stmt};
+use rustc_ast::visit::{Visitor, walk_crate, walk_expr, walk_item, walk_pat, walk_stmt, walk_ty};
+use rustc_ast::{Crate, Expr, Item, Pat, PatKind, Stmt, Ty};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_span::source_map::SourceMap;
 use rustc_span::{BytePos, Span};
@@ -153,4 +153,12 @@ impl<'ast> Visitor<'ast> for ExpandedCodeVisitor<'ast> {
             walk_pat(self, pat);
         }
     }
+
+    fn visit_ty(&mut self, ty: &'ast Ty) {
+        if ty.span.from_expansion() {
+            self.handle_new_span(ty.span, || rustc_ast_pretty::pprust::ty_to_string(ty));
+        } else {
+            walk_ty(self, ty);
+        }
+    }
 }

tests/rustdoc/macro-expansion/type-macro-expansion.rs

@@ -0,0 +1,28 @@
+// Ensure macro invocations at type position are expanded correctly
+
+//@ compile-flags: -Zunstable-options --generate-macro-expansion
+
+#![crate_name = "foo"]
+
+//@ has 'src/foo/type-macro-expansion.rs.html'
+
+macro_rules! foo {
+    () => {
+        fn(())
+    };
+    ($_arg:expr) => {
+        [(); 1]
+    };
+}
+
+fn bar() {
+    //@ has - '//*[@class="expansion"]/*[@class="original"]/*[@class="macro"]' 'foo!'
+    //@ has - '//*[@class="expansion"]/*[@class="original"]' 'foo!()'
+    //@ has - '//*[@class="expansion"]/*[@class="expanded"]' 'fn(())'
+    let _: foo!();
+    //@ has - '//*[@class="expansion"]/*[@class="original"]/*[@class="macro"]' 'foo!'
+    //@ has - '//*[@class="expansion"]/*[@class="original"]' 'foo!(42)'
+    //@ has - '//*[@class="expansion"]/*[@class="expanded"]' '[(); 1]'  
+    let _: foo!(42);
+}
+