Merge #10689

10689: Handle pub tuple fields in tuple structs r=Veykril a=adamrk

The current implementation will throw a parser error for tuple structs
that contain a pub tuple field. For example,
```rust
struct Foo(pub (u32, u32));
```
is valid Rust, but rust-analyzer will throw a parser error.  This is
because the parens after `pub` is treated as a visibility context.
Allowing a tuple type to follow `pub` in the special case when we are
defining fields in a tuple struct can fix the issue.

I guess this is a really minor case because there's not much reason
for having a tuple type within a struct tuple, but it is valid rust syntax...

Co-authored-by: Adam Bratschi-Kaye <[email protected]>

Author: bors[bot]

crates/parser/src/grammar.rs

@@ -75,7 +75,7 @@ pub(crate) mod entry_points {
     }
 
     pub(crate) fn visibility(p: &mut Parser) {
-        let _ = opt_visibility(p);
+        let _ = opt_visibility(p, false);
     }
 
     // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
@@ -149,7 +149,7 @@ impl BlockLike {
     }
 }
 
-fn opt_visibility(p: &mut Parser) -> bool {
+fn opt_visibility(p: &mut Parser, in_tuple_field: bool) -> bool {
     match p.current() {
         T![pub] => {
             let m = p.start();
@@ -165,9 +165,17 @@ fn opt_visibility(p: &mut Parser) -> bool {
                     // struct B(pub (super::A));
                     // struct B(pub (crate::A,));
                     T![crate] | T![self] | T![super] | T![ident] if p.nth(2) != T![:] => {
-                        p.bump(T!['(']);
-                        paths::use_path(p);
-                        p.expect(T![')']);
+                        // If we are in a tuple struct, then the parens following `pub`
+                        // might be an tuple field, not part of the visibility. So in that
+                        // case we don't want to consume an identifier.
+
+                        // test pub_tuple_field
+                        // struct MyStruct(pub (u32, u32));
+                        if !(in_tuple_field && matches!(p.nth(1), T![ident])) {
+                            p.bump(T!['(']);
+                            paths::use_path(p);
+                            p.expect(T![')']);
+                        }
                     }
                     // test crate_visibility_in
                     // pub(in super::A) struct S;

crates/parser/src/grammar/items.rs

@@ -87,7 +87,7 @@ pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
 pub(super) fn opt_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
     // test_err pub_expr
     // fn foo() { pub 92; }
-    let has_visibility = opt_visibility(p);
+    let has_visibility = opt_visibility(p, false);
 
     let m = match opt_item_without_modifiers(p, m) {
         Ok(()) => return Ok(()),

crates/parser/src/grammar/items/adt.rs

@@ -128,7 +128,7 @@ pub(crate) fn record_field_list(p: &mut Parser) {
         // test record_field_attrs
         // struct S { #[attr] f: f32 }
         attributes::outer_attrs(p);
-        opt_visibility(p);
+        opt_visibility(p, false);
         if p.at(IDENT) {
             name(p);
             p.expect(T![:]);
@@ -150,7 +150,7 @@ fn tuple_field_list(p: &mut Parser) {
         // test tuple_field_attrs
         // struct S (#[attr] f32);
         attributes::outer_attrs(p);
-        opt_visibility(p);
+        opt_visibility(p, true);
         if !p.at_ts(types::TYPE_FIRST) {
             p.error("expected a type");
             m.complete(p, ERROR);

crates/syntax/test_data/parser/inline/ok/0196_pub_tuple_field.rast

@@ -0,0 +1,30 @@
+[email protected]
+  [email protected]
+    [email protected] "struct"
+    [email protected] " "
+    [email protected]
+      [email protected] "MyStruct"
+    [email protected]
+      [email protected] "("
+      [email protected]
+        [email protected]
+          [email protected] "pub"
+        [email protected] " "
+        [email protected]
+          [email protected] "("
+          [email protected]
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected] "u32"
+          [email protected] ","
+          [email protected] " "
+          [email protected]
+            [email protected]
+              [email protected]
+                [email protected]
+                  [email protected] "u32"
+          [email protected] ")"
+      [email protected] ")"
+    [email protected] ";"
+  [email protected] "\n"

crates/syntax/test_data/parser/inline/ok/0196_pub_tuple_field.rs

@@ -0,0 +1 @@
+struct MyStruct(pub (u32, u32));