Rollup merge of #134834 - dtolnay:unnamedcall, r=compiler-errors

Skip parenthesis around tuple struct field calls

The pretty-printer previously did not distinguish between named vs unnamed fields when printing a function call containing a struct field. It would print the call as `(self.fun)()` for a named field which is correct, and `(self.0)()` for an unnamed field which is redundant.

This PR changes function calls of tuple struct fields to print without parens.

**Before:**

```rust
struct Tuple(fn());

fn main() {
    let tuple = Tuple(|| {});
    (tuple.0)();
}
```

**After:**

```rust
struct Tuple(fn());

fn main() {
    let tuple = Tuple(|| {});
    tuple.0();
}
```

1 files changed, 3 insertions, 0 deletions

diff --git a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
index dc45731dce7..2b41020d307 100644
--- a/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
+++ b/tests/ui-fulldeps/pprust-parenthesis-insertion.rs
@@ -77,6 +77,9 @@ static EXPRS: &[&str] = &[
     // These mean different things.
     "if let _ = true && false {}",
     "if let _ = (true && false) {}",
+    // Parentheses to call a named field, but not an unnamed field.
+    "(self.fun)()",
+    "self.0()",
     // Conditions end at the first curly brace, so struct expressions need to be
     // parenthesized. Except in a match guard, where conditions end at arrow.
     "if let _ = (Struct {}) {}",