Retain trailing comments in module when using rustfmt::skip attribute

Resolves 5033

Trailing comments at the end of the root Module were removed because the
module span did not extend until the end of the file.

The root Module's span now encompasses the entire file, which ensures
that no comments are lost when using ``#![rustfmt::skip]``

3 files changed, 23 insertions, 2 deletions

diff --git a/src/modules.rs b/src/modules.rs
index 88d434d759d..9e75f41ae36 100644
--- a/src/modules.rs
+++ b/src/modules.rs
@@ -16,7 +16,7 @@ use crate::syntux::parser::{
     Directory, DirectoryOwnership, ModError, ModulePathSuccess, Parser, ParserError,
 };
 use crate::syntux::session::ParseSess;
-use crate::utils::contains_skip;
+use crate::utils::{contains_skip, mk_sp};
 
 mod visitor;
 
@@ -135,10 +135,12 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
             self.visit_mod_from_ast(&krate.items)?;
         }
 
+        let snippet_provider = self.parse_sess.snippet_provider(krate.span);
+
         self.file_map.insert(
             root_filename,
             Module::new(
-                krate.span,
+                mk_sp(snippet_provider.start_pos(), snippet_provider.end_pos()),
                 None,
                 Cow::Borrowed(&krate.items),
                 Cow::Borrowed(&krate.attrs),
diff --git a/tests/target/issue-5033/minimum_example.rs b/tests/target/issue-5033/minimum_example.rs
new file mode 100644
index 00000000000..0e7df41deb2
--- /dev/null
+++ b/tests/target/issue-5033/minimum_example.rs
@@ -0,0 +1,8 @@
+// leading comment
+
+#![rustfmt::skip]
+fn main() {
+    println!("main"); // commented
+}
+
+// post comment
diff --git a/tests/target/issue-5033/nested_modules.rs b/tests/target/issue-5033/nested_modules.rs
new file mode 100644
index 00000000000..7a11133b60b
--- /dev/null
+++ b/tests/target/issue-5033/nested_modules.rs
@@ -0,0 +1,11 @@
+#![rustfmt::skip]
+
+mod a {
+    mod b {
+
+    }
+
+    // trailing comment b
+}
+
+// trailing comment a