Only capture tokens for items with outer attributes

Suggested by @petrochenkov in https://github.com/rust-lang/rust/issues/43081#issuecomment-633389225

3 files changed, 18 insertions, 7 deletions

diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 4fe0453e9c8..6f13d7994d1 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -106,11 +106,20 @@ impl<'a> Parser<'a> {
         });
 
         let mut unclosed_delims = vec![];
-        let (mut item, tokens) = self.collect_tokens(|this| {
+        let has_attrs = !attrs.is_empty();
+        let parse_item = |this: &mut Self| {
             let item = this.parse_item_common_(attrs, mac_allowed, attrs_allowed, req_name);
             unclosed_delims.append(&mut this.unclosed_delims);
             item
-        })?;
+        };
+
+        let (mut item, tokens) = if has_attrs {
+            let (item, tokens) = self.collect_tokens(parse_item)?;
+            (item, Some(tokens))
+        } else {
+            (parse_item(self)?, None)
+        };
+
         self.unclosed_delims.append(&mut unclosed_delims);
 
         // Once we've parsed an item and recorded the tokens we got while
@@ -127,9 +136,11 @@ impl<'a> Parser<'a> {
         // it (bad!). To work around this case for now we just avoid recording
         // `tokens` if we detect any inner attributes. This should help keep
         // expansion correct, but we should fix this bug one day!
-        if let Some(item) = &mut item {
-            if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
-                item.tokens = Some(tokens);
+        if let Some(tokens) = tokens {
+            if let Some(item) = &mut item {
+                if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
+                    item.tokens = Some(tokens);
+                }
             }
         }
         Ok(item)
diff --git a/src/test/ui/ast-json/ast-json-noexpand-output.stdout b/src/test/ui/ast-json/ast-json-noexpand-output.stdout
index f60b6a00be1..c7b0fbeb0e3 100644
--- a/src/test/ui/ast-json/ast-json-noexpand-output.stdout
+++ b/src/test/ui/ast-json/ast-json-noexpand-output.stdout
@@ -1 +1 @@
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+{"module":{"inner":{"lo":0,"hi":0},"items":[{"attrs":[],"id":0,"span":{"lo":0,"hi":0},"vis":{"node":"Inherited","span":{"lo":0,"hi":0}},"ident":{"name":"core","span":{"lo":0,"hi":0}},"kind":{"variant":"ExternCrate","fields":[null]},"tokens":null}],"inline":true},"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"crate_type","span":{"lo":0,"hi":0}},"id":0,"args":null}]},"args":{"variant":"Eq","fields":[{"lo":0,"hi":0},{"_field0":[[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"NonJoint"]]}]}}]},"id":null,"style":"Inner","span":{"lo":0,"hi":0}}],"span":{"lo":0,"hi":0},"proc_macros":[]}
diff --git a/src/test/ui/ast-json/ast-json-output.stdout b/src/test/ui/ast-json/ast-json-output.stdout
index 42e7e789980..59ed68c2a77 100644
--- a/src/test/ui/ast-json/ast-json-output.stdout
+++ b/src/test/ui/ast-json/ast-json-output.stdout
@@ -1 +1 @@
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