Update to rustfmt 1.6.0-nightly (839e9a6 2023-07-02)

Summary:
Update to rustfmt 1.6.0-nightly (839e9a6 2023-07-02)

The big ticket item here is that let-else is now supported! In fact, the
suppport just landed two days ago (see [rust-lang/rustfmt#4914])

The unfortunate thing here though is that rustfmt is not statically
linked anymore (see discussion in [rust-lang/rust#107297]). So we need
all of librustc_driver and libstd - which makes our use case pretty big
(~4-5MB to 50MB-100MB). We should explore building from source and
statically linking, or using rustfmt from the toolchain. Both things
that I don't want to deal with right now.

[rust-lang/rustfmt#4914]: rust-lang/rustfmt#4914
[rust-lang/rust#107297]: rust-lang/rust#107297

Note to future updaters: To find out more-or-less what libs you need,
you can use `objdump -p bin/rustfmt | grep NEEDED` on Linux for ELF
bins, and `otool -L bin/rustfmt` on macOS for Mach-O bins. No idea what
you do for Windows.

Ran `tools/arcanist/lint/codemods/rustfmt-fbsource` to format the repo.

Reviewed By: shayne-fletcher

Differential Revision: D47203254

fbshipit-source-id: 6ffd3ce66c7f2b006d09505b93fed515ebc76902

Author: zertosh

hphp/hack/src/elab/passes/elab_dynamic_class_name.rs

@@ -192,7 +192,7 @@ mod tests {
             expr_,
             Expr_::FunctionPointer(box (
                 FunctionPtrId::FPClassConst(ClassId(_, _, ClassId_::CIself), _),
-                _
+                _,
             ))
         ));
     }
@@ -234,11 +234,7 @@ mod tests {
         assert!(env.into_errors().is_empty());
         assert!(matches!(
             elem,
-            Expr(
-                _,
-                _,
-                Expr_::ClassConst(box (ClassId(_, _, ClassId_::CIself), _))
-            )
+            Expr(_, _, Expr_::ClassConst(box (ClassId(_, _, ClassId_::CIself), _)))
         ))
     }
 
@@ -263,8 +259,8 @@ mod tests {
                 Expr_::Invalid(box Some(Expr(
                     _,
                     _,
-                    Expr_::ClassConst(box (ClassId(_, _, ClassId_::CIexpr(..)), _))
-                )))
+                    Expr_::ClassConst(box (ClassId(_, _, ClassId_::CIexpr(..)), _)),
+                ))),
             )
         ))
     }
@@ -289,11 +285,7 @@ mod tests {
         assert!(env.into_errors().is_empty());
         assert!(matches!(
             elem,
-            Expr(
-                _,
-                _,
-                Expr_::ClassGet(box (ClassId(_, _, ClassId_::CIself), _, _))
-            )
+            Expr(_, _, Expr_::ClassGet(box (ClassId(_, _, ClassId_::CIself), _, _)))
         ))
     }
 

hphp/hack/src/elab/passes/elab_hint_haccess.rs

@@ -329,10 +329,7 @@ mod tests {
         let Contexts(_, mut hints) = elem;
         assert!(matches!(
             hints.pop(),
-            Some(Hint(
-                _,
-                box Hint_::Haccess(Hint(_, box Hint_::Habstr(..)), _)
-            ))
+            Some(Hint(_, box Hint_::Haccess(Hint(_, box Hint_::Habstr(..)), _)))
         ))
     }
 

hphp/hack/src/elab/passes/elab_hint_happly.rs

@@ -378,7 +378,7 @@ mod tests {
         assert!(matches!(
             elem,
             ClassTypeconst::TCConcrete(ClassConcreteTypeconst {
-                c_tc_type: Hint(_, box Hint_::Hprim(Tprim::Tint))
+                c_tc_type: Hint(_, box Hint_::Hprim(Tprim::Tint)),
             })
         ))
     }

hphp/hack/src/hackc/ir/conversions/textual/textual.rs

@@ -361,7 +361,9 @@ impl<'a> TextualFile<'a> {
         let curry_ty = curry.ty_name();
         let mut fields = Vec::new();
         if curry.virtual_call {
-            let FunctionName::Method(captured_this_ty, _) = &curry.name else { unreachable!(); };
+            let FunctionName::Method(captured_this_ty, _) = &curry.name else {
+                unreachable!();
+            };
             fields.push(Field {
                 name: "this".into(),
                 ty: Ty::named_type_ptr(captured_this_ty.clone()).into(),
@@ -589,7 +591,9 @@ impl Ty {
     }
 
     pub(crate) fn deref(&self) -> Ty {
-        let Some(ty) = self.try_deref() else { panic!("Unable to deref {self:?}"); };
+        let Some(ty) = self.try_deref() else {
+            panic!("Unable to deref {self:?}");
+        };
         ty
     }
 
@@ -1125,7 +1129,9 @@ impl FuncBuilder<'_, '_> {
         let obj = self.write_expr_stmt(Expr::Alloc(ty.clone()))?;
 
         if let Some(this) = this {
-            let FunctionName::Method(captured_this_ty, _) = &name else { unreachable!(); };
+            let FunctionName::Method(captured_this_ty, _) = &name else {
+                unreachable!();
+            };
             self.store(
                 Expr::Field(Box::new(obj.into()), ty.clone(), "this".to_string()),
                 this,