Rollup merge of #125236 - dtolnay:expandtest, r=nnethercote

Add tests for `-Zunpretty=expanded` ported from stringify's tests

This PR adds a new set of tests for the AST pretty-printer.

Previously, pretty-printer edge cases were tested by way of `stringify!` in [tests/ui/macros/stringify.rs](https://github.com/rust-lang/rust/blob/1.78.0/tests/ui/macros/stringify.rs), such as the tests added by 419b26931b and 527e2eac17.

Those tests will no longer provide effective coverage of the AST pretty-printer after #124141. `Nonterminal` and `TokenKind::Interpolated` are being removed, and a consequence is that `stringify!` will perform token stream pretty printing, instead of AST pretty printing, in all of the `stringify!` cases including $:expr and all other interpolations.

This PR adds 2 new ui tests with `compile-flags: -Zunpretty=expanded`:

- **tests/ui/unpretty/expanded-exhaustive.rs** — this test aims for exhaustive coverage of all the variants of `ExprKind`, `ItemKind`, `PatKind`, `StmtKind`, `TyKind`, and `VisibilityKind`. Some parts could use being fleshed out further, but the current state is roughly on par with what exists in the old stringify-based tests.

- **tests/ui/unpretty/expanded-interpolation.rs** — this test covers tricky macro metavariable edge cases that require the AST pretty printer to synthesize parentheses in order for the printed code to be valid Rust syntax.

r? `@nnethercote`

src/tools/tidy/src/issues.txt

@@ -2915,7 +2915,6 @@ ui/macros/issue-95267.rs
 ui/macros/issue-95533.rs
 ui/macros/issue-98466-allow.rs
 ui/macros/issue-98466.rs
-ui/macros/issue-98790.rs
 ui/macros/issue-99261.rs
 ui/macros/issue-99265.rs
 ui/macros/issue-99907.rs

src/tools/tidy/src/ui_tests.rs

@@ -41,6 +41,7 @@
     "tests/ui/macros/not-utf8.bin", // testing including data with the include macros
     "tests/ui/macros/syntax-extension-source-utils-files/includeme.fragment", // more include
     "tests/ui/proc-macro/auxiliary/included-file.txt", // more include
+    "tests/ui/unpretty/auxiliary/data.txt", // more include
     "tests/ui/invalid/foo.natvis.xml", // sample debugger visualizer
     "tests/ui/sanitizer/dataflow-abilist.txt", // dataflow sanitizer ABI list file
     "tests/ui/shell-argfiles/shell-argfiles.args", // passing args via a file

tests/ui/macros/issue-98790.rs

@@ -1,24 +0,0 @@
-//@ run-pass
-
-macro_rules! stringify_item {
-    ($item:item) => {
-        stringify!($item)
-    };
-}
-
-macro_rules! repro {
-    ($expr:expr) => {
-        stringify_item! {
-            pub fn repro() -> bool {
-                $expr
-            }
-        }
-    };
-}
-
-fn main() {
-    assert_eq!(
-        repro!(match () { () => true } | true),
-        "pub fn repro() -> bool { (match () { () => true, }) | true }"
-    );
-}

tests/ui/unpretty/auxiliary/data.txt

@@ -0,0 +1 @@
+data for include_bytes in ../expanded-exhaustive.rs

tests/ui/unpretty/expanded-exhaustive.rs

@@ -0,0 +1,888 @@
+//@ compile-flags: -Zunpretty=expanded -Zunstable-options
+//@ edition:2024
+//@ check-pass
+
+#![feature(async_closure)]
+#![feature(auto_traits)]
+#![feature(box_patterns)]
+#![feature(builtin_syntax)]
+#![feature(concat_idents)]
+#![feature(const_trait_impl)]
+#![feature(core_pattern_type)]
+#![feature(decl_macro)]
+#![feature(deref_patterns)]
+#![feature(explicit_tail_calls)]
+#![feature(gen_blocks)]
+#![feature(let_chains)]
+#![feature(more_qualified_paths)]
+#![feature(never_patterns)]
+#![feature(never_type)]
+#![feature(pattern_types)]
+#![feature(prelude_import)]
+#![feature(raw_ref_op)]
+#![feature(specialization)]
+#![feature(trace_macros)]
+#![feature(trait_alias)]
+#![feature(try_blocks)]
+#![feature(unnamed_fields)]
+#![feature(yeet_expr)]
+#![allow(incomplete_features)]
+
+#[prelude_import]
+use self::prelude::*;
+
+mod prelude {
+    pub use std::prelude::rust_2024::*;
+
+    pub type T = _;
+
+    pub trait Trait {
+        const CONST: ();
+    }
+}
+
+mod attributes {
+    //! inner single-line doc comment
+    /*!
+     * inner multi-line doc comment
+     */
+    #![doc = "inner doc attribute"]
+    #![allow(dead_code, unused_variables)]
+    #![no_std]
+
+    /// outer single-line doc comment
+    /**
+     * outer multi-line doc comment
+     */
+    #[doc = "outer doc attribute"]
+    #[doc = concat!("mac", "ro")]
+    #[allow()]
+    #[repr(C)]
+    struct Struct;
+}
+
+mod expressions {
+    /// ExprKind::Array
+    fn expr_array() {
+        [];
+        [true];
+        [true,];
+        [true, true];
+        ["long........................................................................"];
+        ["long............................................................", true];
+    }
+
+    /// ExprKind::ConstBlock
+    fn expr_const_block() {
+        const {};
+        const { 1 };
+        const { struct S; };
+    }
+
+    /// ExprKind::Call
+    fn expr_call() {
+        let f;
+        f();
+        f::<u8>();
+        f::<1>();
+        f::<'static, u8, 1>();
+        f(true);
+        f(true,);
+        ()();
+    }
+
+    /// ExprKind::MethodCall
+    fn expr_method_call() {
+        let x;
+        x.f();
+        x.f::<u8>();
+        x.collect::<Vec<_>>();
+    }
+
+    /// ExprKind::Tup
+    fn expr_tup() {
+        ();
+        (true,);
+        (true, false);
+        (true, false,);
+    }
+
+    /// ExprKind::Binary
+    fn expr_binary() {
+        let (a, b, c, d, x, y);
+        true || false;
+        true || false && false;
+        a < 1 && 2 < b && c > 3 && 4 > d;
+        a & b & !c;
+        a + b * c - d + -1 * -2 - -3;
+        x = !y;
+    }
+
+    /// ExprKind::Unary
+    fn expr_unary() {
+        let expr;
+        *expr;
+        !expr;
+        -expr;
+    }
+
+    /// ExprKind::Lit
+    fn expr_lit() {
+        'x';
+        1_000_i8;
+        1.00000000000000000000001;
+    }
+
+    /// ExprKind::Cast
+    fn expr_cast() {
+        let expr;
+        expr as T;
+        expr as T<u8>;
+    }
+
+    /// ExprKind::Type
+    fn expr_type() {
+        let expr;
+        builtin # type_ascribe(expr, T);
+    }
+
+    /// ExprKind::Let
+    fn expr_let() {
+        let b;
+        if let Some(a) = b {}
+        if let _ = true && false {}
+        if let _ = (true && false) {}
+    }
+
+    /// ExprKind::If
+    fn expr_if() {
+        if true {}
+        if !true {}
+        if let true = true {} else {}
+        if true {} else if false {}
+        if true {} else if false {} else {}
+        if true { return; } else if false { 0 } else { 0 }
+    }
+
+    /// ExprKind::While
+    fn expr_while() {
+        while false {}
+        'a: while false {}
+        while let true = true {}
+    }
+
+    /// ExprKind::ForLoop
+    fn expr_for_loop() {
+        let x;
+        for _ in x {}
+        'a: for _ in x {}
+    }
+
+    /// ExprKind::Loop
+    fn expr_loop() {
+        loop {}
+        'a: loop {}
+    }
+
+    /// ExprKind::Match
+    fn expr_match() {
+        let value;
+        match value {}
+        match value { ok => 1 }
+        match value {
+            ok => 1,
+            err => 0,
+        }
+    }
+
+    /// ExprKind::Closure
+    fn expr_closure() {
+        let value;
+        || {};
+        |x| {};
+        |x: u8| {};
+        || ();
+        move || value;
+        async || value;
+        async move || value;
+        static || value;
+        static move || value;
+        (static async || value);
+        (static async move || value);
+        || -> u8 { value };
+        1 + || {};
+    }
+
+    /// ExprKind::Block
+    fn expr_block() {
+        {}
+        unsafe {}
+        'a: {}
+        #[allow()] {}
+        { #![allow()] }
+    }
+
+    /// ExprKind::Gen
+    fn expr_gen() {
+        async {};
+        async move {};
+        gen {};
+        gen move {};
+        async gen {};
+        async gen move {};
+    }
+
+    /// ExprKind::Await
+    fn expr_await() {
+        let fut;
+        fut.await;
+    }
+
+    /// ExprKind::TryBlock
+    fn expr_try_block() {
+        try {}
+        try { return; }
+    }
+
+    /// ExprKind::Assign
+    fn expr_assign() {
+        let expr;
+        expr = true;
+    }
+
+    /// ExprKind::AssignOp
+    fn expr_assign_op() {
+        let expr;
+        expr += true;
+    }
+
+    /// ExprKind::Field
+    fn expr_field() {
+        let expr;
+        expr.field;
+        expr.0;
+    }
+
+    /// ExprKind::Index
+    fn expr_index() {
+        let expr;
+        expr[true];
+    }
+
+    /// ExprKind::Range
+    fn expr_range() {
+        let (lo, hi);
+        ..;
+        ..hi;
+        lo..;
+        lo..hi;
+        lo .. hi;
+        ..=hi;
+        lo..=hi;
+        -2..=-1;
+    }
+
+    /// ExprKind::Underscore
+    fn expr_underscore() {
+        _;
+    }
+
+    /// ExprKind::Path
+    fn expr_path() {
+        let x;
+        crate::expressions::expr_path;
+        crate::expressions::expr_path::<'static>;
+        <T as Default>::default;
+        <T as ::core::default::Default>::default::<>;
+        x::();
+        x::(T, T) -> T;
+        crate::() -> ()::expressions::() -> ()::expr_path;
+        core::()::marker::()::PhantomData;
+    }
+
+    /// ExprKind::AddrOf
+    fn expr_addr_of() {
+        let expr;
+        &expr;
+        &mut expr;
+        &raw const expr;
+        &raw mut expr;
+    }
+
+    /// ExprKind::Break
+    fn expr_break() {
+        'a: {
+            break;
+            break 'a;
+            break true;
+            break 'a true;
+        }
+    }
+
+    /// ExprKind::Continue
+    fn expr_continue() {
+        'a: {
+            continue;
+            continue 'a;
+        }
+    }
+
+    /// ExprKind::Ret
+    fn expr_ret() {
+        return;
+        return true;
+    }
+
+    /// ExprKind::InlineAsm
+    fn expr_inline_asm() {
+        let x;
+        core::arch::asm!(
+            "mov {tmp}, {x}",
+            "shl {tmp}, 1",
+            "shl {x}, 2",
+            "add {x}, {tmp}",
+            x = inout(reg) x,
+            tmp = out(reg) _,
+        );
+    }
+
+    /// ExprKind::OffsetOf
+    fn expr_offset_of() {
+        core::mem::offset_of!(T, field);
+    }
+
+    /// ExprKind::MacCall
+    fn expr_mac_call() {
+        stringify!(...);
+        stringify![...];
+        stringify! { ... };
+    }
+
+    /// ExprKind::Struct
+    fn expr_struct() {
+        struct Struct {}
+        let (x, base);
+        Struct {};
+        <Struct as ToOwned>::Owned {};
+        Struct { .. };
+        Struct { .. base };
+        Struct { x };
+        Struct { x, ..base };
+        Struct { x: true };
+        Struct { x: true, .. };
+        Struct { x: true, ..base };
+        Struct { 0: true, ..base };
+    }
+
+    /// ExprKind::Repeat
+    fn expr_repeat() {
+        [(); 0];
+    }
+
+    /// ExprKind::Paren
+    fn expr_paren() {
+        let expr;
+        (expr);
+    }
+
+    /// ExprKind::Try
+    fn expr_try() {
+        let expr;
+        expr?;
+    }
+
+    /// ExprKind::Yield
+    fn expr_yield() {
+        yield;
+        yield true;
+    }
+
+    /// ExprKind::Yeet
+    fn expr_yeet() {
+        do yeet;
+        do yeet 0;
+    }
+
+    /// ExprKind::Become
+    fn expr_become() {
+        become true;
+    }
+
+    /// ExprKind::IncludedBytes
+    fn expr_include_bytes() {
+        include_bytes!("auxiliary/data.txt");
+    }
+
+    /// ExprKind::FormatArgs
+    fn expr_format_args() {
+        let expr;
+        format_args!("");
+        format_args!("{}", expr);
+    }
+}
+
+mod items {
+    /// ItemKind::ExternCrate
+    mod item_extern_crate {
+        extern crate core;
+        extern crate self as unpretty;
+        pub extern crate core as _;
+    }
+
+    /// ItemKind::Use
+    mod item_use {
+        use crate::{expressions, items::item_use};
+        pub use core::*;
+    }
+
+    /// ItemKind::Static
+    mod item_static {
+        pub static A: () = {};
+        static mut B: () = {};
+    }
+
+    /// ItemKind::Const
+    mod item_const {
+        pub const A: () = {};
+
+        trait TraitItems {
+            const B: ();
+            const C: () = {};
+        }
+    }
+
+    /// ItemKind::Fn
+    mod item_fn {
+        pub const unsafe extern "C" fn f() {}
+        pub async unsafe extern fn g() {}
+        fn h<'a, T>() where T: 'a {}
+
+        trait TraitItems {
+            unsafe extern fn f();
+        }
+
+        impl TraitItems for _ {
+            default unsafe extern fn f() {}
+        }
+    }
+
+    /// ItemKind::Mod
+    mod item_mod {
+        // ...
+    }
+
+    /// ItemKind::ForeignMod
+    mod item_foreign_mod {
+        extern "C++" {}
+        extern {}
+    }
+
+    /// ItemKind::GlobalAsm
+    mod item_global_asm {
+        core::arch::global_asm!(".globl my_asm_func");
+    }
+
+    /// ItemKind::TyAlias
+    mod item_ty_alias {
+        pub type Type<'a> where T: 'a, = T;
+    }
+
+    /// ItemKind::Enum
+    mod item_enum {
+        pub enum Void {}
+        enum Empty {
+            Unit,
+            Tuple(),
+            Struct {},
+        }
+        enum Generic<'a, T>
+        where
+            T: 'a,
+        {
+            Tuple(T),
+            Struct { t: T },
+        }
+    }
+
+    /// ItemKind::Struct
+    mod item_struct {
+        pub struct Unit;
+        struct Tuple();
+        struct Newtype(Unit);
+        struct Struct {}
+        struct Generic<'a, T>
+        where
+            T: 'a,
+        {
+            t: T,
+        }
+    }
+
+    /// ItemKind::Union
+    mod item_union {
+        union Generic<'a, T>
+        where
+            T: 'a,
+        {
+            t: T,
+        }
+    }
+
+    /// ItemKind::Trait
+    mod item_trait {
+        pub unsafe auto trait Send {}
+        trait Trait<'a>: Sized
+        where
+            Self: 'a,
+        {
+        }
+    }
+
+    /// ItemKind::TraitAlias
+    mod item_trait_alias {
+        pub trait Trait<T> = Sized where for<'a> T: 'a;
+    }
+
+    /// ItemKind::Impl
+    mod item_impl {
+        impl () {}
+        impl<T> () {}
+        impl Default for () {}
+        impl<T> const Default for () {}
+    }
+
+    /// ItemKind::MacCall
+    mod item_mac_call {
+        trace_macros!(false);
+        trace_macros![false];
+        trace_macros! { false }
+    }
+
+    /// ItemKind::MacroDef
+    mod item_macro_def {
+        macro_rules! mac { () => {...}; }
+        pub macro stringify() {}
+    }
+
+    /// ItemKind::Delegation
+    mod item_delegation {
+        /*! FIXME: todo */
+    }
+
+    /// ItemKind::DelegationMac
+    mod item_delegation_mac {
+        /*! FIXME: todo */
+    }
+}
+
+mod patterns {
+    /// PatKind::Wild
+    fn pat_wild() {
+        let _;
+    }
+
+    /// PatKind::Ident
+    fn pat_ident() {
+        let x;
+        let ref x;
+        let mut x;
+        let ref mut x;
+        let ref mut x @ _;
+    }
+
+    /// PatKind::Struct
+    fn pat_struct() {
+        let T {};
+        let T::<T> {};
+        let T::<'static> {};
+        let T { x };
+        let T { x: _x };
+        let T { .. };
+        let T { x, .. };
+        let T { x: _x, .. };
+        let T { 0: _x, .. };
+        let <T as ToOwned>::Owned {};
+    }
+
+    /// PatKind::TupleStruct
+    fn pat_tuple_struct() {
+        struct Tuple();
+        let Tuple();
+        let Tuple::<T>();
+        let Tuple::<'static>();
+        let Tuple(x);
+        let Tuple(..);
+        let Tuple(x, ..);
+    }
+
+    /// PatKind::Or
+    fn pat_or() {
+        let (true | false);
+        let (| true);
+        let (|true| false);
+    }
+
+    /// PatKind::Path
+    fn pat_path() {
+        let core::marker::PhantomData;
+        let core::marker::PhantomData::<T>;
+        let core::marker::PhantomData::<'static>;
+        let <T as Trait>::CONST;
+    }
+
+    /// PatKind::Tuple
+    fn pat_tuple() {
+        let ();
+        let (true,);
+        let (true, false);
+    }
+
+    /// PatKind::Box
+    fn pat_box() {
+        let box pat;
+    }
+
+    /// PatKind::Deref
+    fn pat_deref() {
+        let deref!(pat);
+    }
+
+    /// PatKind::Ref
+    fn pat_ref() {
+        let &pat;
+        let &mut pat;
+    }
+
+    /// PatKind::Lit
+    fn pat_lit() {
+        let 1_000_i8;
+        let -"";
+    }
+
+    /// PatKind::Range
+    fn pat_range() {
+        let ..1;
+        let 0..;
+        let 0..1;
+        let 0..=1;
+        let -2..=-1;
+    }
+
+    /// PatKind::Slice
+    fn pat_slice() {
+        let [];
+        let [true];
+        let [true,];
+        let [true, false];
+    }
+
+    /// PatKind::Rest
+    fn pat_rest() {
+        let ..;
+    }
+
+    /// PatKind::Never
+    fn pat_never() {
+        let !;
+        let Some(!);
+    }
+
+    /// PatKind::Paren
+    fn pat_paren() {
+        let (pat);
+    }
+
+    /// PatKind::MacCall
+    fn pat_mac_call() {
+        let stringify!();
+        let stringify![];
+        let stringify! {};
+    }
+}
+
+mod statements {
+    /// StmtKind::Let
+    fn stmt_let() {
+        let _;
+        let _ = true;
+        let _: T = true;
+        let _ = true else { return; };
+    }
+
+    /// StmtKind::Item
+    fn stmt_item() {
+        struct Struct {}
+        struct Unit;
+    }
+
+    /// StmtKind::Expr
+    fn stmt_expr() {
+        ()
+    }
+
+    /// StmtKind::Semi
+    fn stmt_semi() {
+        1 + 1;
+    }
+
+    /// StmtKind::Empty
+    fn stmt_empty() {
+        ;
+    }
+
+    /// StmtKind::MacCall
+    fn stmt_mac_call() {
+        stringify!(...);
+        stringify![...];
+        stringify! { ... };
+    }
+}
+
+mod types {
+    /// TyKind::Slice
+    fn ty_slice() {
+        let _: [T];
+    }
+
+    /// TyKind::Array
+    fn ty_array() {
+        let _: [T; 0];
+    }
+
+    /// TyKind::Ptr
+    fn ty_ptr() {
+        let _: *const T;
+        let _: *mut T;
+    }
+
+    /// TyKind::Ref
+    fn ty_ref() {
+        let _: &T;
+        let _: &mut T;
+        let _: &'static T;
+        let _: &'static mut [T];
+        let _: &T<T<T<T<T>>>>;
+        let _: &T<T<T<T<T> > > >;
+    }
+
+    /// TyKind::BareFn
+    fn ty_bare_fn() {
+        let _: fn();
+        let _: fn() -> ();
+        let _: fn(T);
+        let _: fn(t: T);
+        let _: for<> fn();
+        let _: for<'a> fn();
+    }
+
+    /// TyKind::Never
+    fn ty_never() {
+        let _: !;
+    }
+
+    /// TyKind::Tup
+    fn ty_tup() {
+        let _: ();
+        let _: (T,);
+        let _: (T, T);
+    }
+
+    /// TyKind::AnonStruct
+    fn ty_anon_struct() {
+        struct Struct {
+            _: struct { t: T },
+        }
+    }
+
+    /// TyKind::AnonUnion
+    fn ty_anon_union() {
+        struct Struct {
+            _: union { t: T },
+        }
+    }
+
+    /// TyKind::Path
+    fn ty_path() {
+        let _: T;
+        let _: T<'static>;
+        let _: T<T>;
+        let _: T::<T>;
+        let _: T() -> !;
+        let _: <T as ToOwned>::Owned;
+    }
+
+    /// TyKind::TraitObject
+    fn ty_trait_object() {
+        let _: dyn Send;
+        let _: dyn Send + 'static;
+        let _: dyn 'static + Send;
+        let _: dyn for<'a> Send;
+    }
+
+    /// TyKind::ImplTrait
+    const fn ty_impl_trait() {
+        let _: impl Send;
+        let _: impl Send + 'static;
+        let _: impl 'static + Send;
+        let _: impl ?Sized;
+        let _: impl ~const Clone;
+        let _: impl for<'a> Send;
+    }
+
+    /// TyKind::Paren
+    fn ty_paren() {
+        let _: (T);
+    }
+
+    /// TyKind::Typeof
+    fn ty_typeof() {
+        /*! unused for now */
+    }
+
+    /// TyKind::Infer
+    fn ty_infer() {
+        let _: _;
+    }
+
+    /// TyKind::ImplicitSelf
+    fn ty_implicit_self() {
+        /*! there is no syntax for this */
+    }
+
+    /// TyKind::MacCall
+    fn ty_mac_call() {
+        let _: concat_idents!(T);
+        let _: concat_idents![T];
+        let _: concat_idents! { T };
+    }
+
+    /// TyKind::CVarArgs
+    fn ty_c_var_args() {
+        /*! FIXME: todo */
+    }
+
+    /// TyKind::Pat
+    fn ty_pat() {
+        let _: core::pattern_type!(u32 is 1..);
+    }
+}
+
+mod visibilities {
+    /// VisibilityKind::Public
+    mod visibility_public {
+        pub struct Pub;
+    }
+
+    /// VisibilityKind::Restricted
+    mod visibility_restricted {
+        pub(crate) struct PubCrate;
+        pub(self) struct PubSelf;
+        pub(super) struct PubSuper;
+        pub(in crate) struct PubInCrate;
+        pub(in self) struct PubInSelf;
+        pub(in super) struct PubInSuper;
+        pub(in crate::visibilities) struct PubInCrateVisibilities;
+        pub(in self::super) struct PubInSelfSuper;
+        pub(in super::visibility_restricted) struct PubInSuperMod;
+    }
+}

tests/ui/unpretty/expanded-exhaustive.stdout

@@ -0,0 +1,719 @@
+#![feature(prelude_import)]
+//@ compile-flags: -Zunpretty=expanded -Zunstable-options
+//@ edition:2024
+//@ check-pass
+
+#![feature(async_closure)]
+#![feature(auto_traits)]
+#![feature(box_patterns)]
+#![feature(builtin_syntax)]
+#![feature(concat_idents)]
+#![feature(const_trait_impl)]
+#![feature(core_pattern_type)]
+#![feature(decl_macro)]
+#![feature(deref_patterns)]
+#![feature(explicit_tail_calls)]
+#![feature(gen_blocks)]
+#![feature(let_chains)]
+#![feature(more_qualified_paths)]
+#![feature(never_patterns)]
+#![feature(never_type)]
+#![feature(pattern_types)]
+#![feature(prelude_import)]
+#![feature(raw_ref_op)]
+#![feature(specialization)]
+#![feature(trace_macros)]
+#![feature(trait_alias)]
+#![feature(try_blocks)]
+#![feature(unnamed_fields)]
+#![feature(yeet_expr)]
+#![allow(incomplete_features)]
+#[prelude_import]
+use std::prelude::rust_2024::*;
+#[macro_use]
+extern crate std;
+
+#[prelude_import]
+use self::prelude::*;
+
+mod prelude {
+    pub use std::prelude::rust_2024::*;
+
+    pub type T = _;
+
+    pub trait Trait {
+        const CONST: ();
+    }
+}
+
+mod attributes {
+    //! inner single-line doc comment
+    /*!
+     * inner multi-line doc comment
+     */
+    #![doc = "inner doc attribute"]
+    #![allow(dead_code, unused_variables)]
+    #![no_std]
+
+    /// outer single-line doc comment
+    /**
+     * outer multi-line doc comment
+     */
+    #[doc = "outer doc attribute"]
+    #[doc = "macro"]
+    #[allow()]
+    #[repr(C)]
+    struct Struct;
+}
+
+mod expressions {
+    /// ExprKind::Array
+    fn expr_array() {
+        [];
+        [true];
+        [true];
+        [true, true];
+        ["long........................................................................"];
+        ["long............................................................",
+                true];
+    }
+
+    /// ExprKind::ConstBlock
+    fn expr_const_block() {
+        const {};
+        const { 1 };
+        const {
+                struct S;
+            };
+    }
+
+    /// ExprKind::Call
+    fn expr_call() {
+        let f;
+        f();
+        f::<u8>();
+        f::<1>();
+        f::<'static, u8, 1>();
+        f(true);
+        f(true);
+        ()();
+    }
+
+    /// ExprKind::MethodCall
+    fn expr_method_call() {
+        let x;
+        x.f();
+        x.f::<u8>();
+        x.collect::<Vec<_>>();
+    }
+
+    /// ExprKind::Tup
+    fn expr_tup() { (); (true,); (true, false); (true, false); }
+
+    /// ExprKind::Binary
+    fn expr_binary() {
+        let (a, b, c, d, x, y);
+        true || false;
+        true || false && false;
+        a < 1 && 2 < b && c > 3 && 4 > d;
+        a & b & !c;
+        a + b * c - d + -1 * -2 - -3;
+        x = !y;
+    }
+
+    /// ExprKind::Unary
+    fn expr_unary() { let expr; *expr; !expr; -expr; }
+
+    /// ExprKind::Lit
+    fn expr_lit() { 'x'; 1_000_i8; 1.00000000000000000000001; }
+
+    /// ExprKind::Cast
+    fn expr_cast() { let expr; expr as T; expr as T<u8>; }
+
+    /// ExprKind::Type
+    fn expr_type() { let expr; builtin # type_ascribe(expr, T); }
+
+    /// ExprKind::Let
+    fn expr_let() {
+        let b;
+        if let Some(a) = b {}
+        if let _ = true && false {}
+        if let _ = (true && false) {}
+    }
+
+    /// ExprKind::If
+    fn expr_if() {
+        if true {}
+        if !true {}
+        if let true = true {} else {}
+        if true {} else if false {}
+        if true {} else if false {} else {}
+        if true { return; } else if false { 0 } else { 0 }
+    }
+
+    /// ExprKind::While
+    fn expr_while() {
+        while false {}
+        'a: while false {}
+        while let true = true {}
+    }
+
+    /// ExprKind::ForLoop
+    fn expr_for_loop() { let x; for _ in x {} 'a: for _ in x {} }
+
+    /// ExprKind::Loop
+    fn expr_loop() { loop {} 'a: loop {} }
+
+    /// ExprKind::Match
+    fn expr_match() {
+        let value;
+        match value {}
+        match value { ok => 1, }
+        match value { ok => 1, err => 0, }
+    }
+
+    /// ExprKind::Closure
+    fn expr_closure() {
+        let value;
+        || {};
+        |x| {};
+        |x: u8| {};
+        || ();
+        move || value;
+        async || value;
+        async move || value;
+        static || value;
+        static move || value;
+        (static async || value);
+        (static async move || value);
+        || -> u8 { value };
+        1 + (|| {});
+    }
+
+    /// ExprKind::Block
+    fn expr_block() {
+        {}
+        unsafe {}
+        'a: {}
+
+        #[allow()]
+        {}
+        {
+            #![allow()]
+        }
+    }
+
+    /// ExprKind::Gen
+    fn expr_gen() {
+        async {};
+        async move {};
+        gen {};
+        gen move {};
+        async gen {};
+        async gen move {};
+    }
+
+    /// ExprKind::Await
+    fn expr_await() { let fut; fut.await; }
+
+    /// ExprKind::TryBlock
+    fn expr_try_block() { try {} try { return; } }
+
+    /// ExprKind::Assign
+    fn expr_assign() { let expr; expr = true; }
+
+    /// ExprKind::AssignOp
+    fn expr_assign_op() { let expr; expr += true; }
+
+    /// ExprKind::Field
+    fn expr_field() { let expr; expr.field; expr.0; }
+
+    /// ExprKind::Index
+    fn expr_index() { let expr; expr[true]; }
+
+    /// ExprKind::Range
+    fn expr_range() {
+        let (lo, hi);
+        ..;
+        ..hi;
+        lo..;
+        lo..hi;
+        lo..hi;
+        ..=hi;
+        lo..=hi;
+        -2..=-1;
+    }
+
+    /// ExprKind::Underscore
+    fn expr_underscore() { _; }
+
+    /// ExprKind::Path
+    fn expr_path() {
+        let x;
+        crate::expressions::expr_path;
+        crate::expressions::expr_path::<'static>;
+        <T as Default>::default;
+        <T as ::core::default::Default>::default::<>;
+        x::();
+        x::(T, T) -> T;
+        crate::() -> ()::expressions::() -> ()::expr_path;
+        core::()::marker::()::PhantomData;
+    }
+
+    /// ExprKind::AddrOf
+    fn expr_addr_of() {
+        let expr;
+        &expr;
+        &mut expr;
+        &raw const expr;
+        &raw mut expr;
+    }
+
+    /// ExprKind::Break
+    fn expr_break() { 'a: { break; break 'a; break true; break 'a true; } }
+
+    /// ExprKind::Continue
+    fn expr_continue() { 'a: { continue; continue 'a; } }
+
+    /// ExprKind::Ret
+    fn expr_ret() { return; return true; }
+
+    /// ExprKind::InlineAsm
+    fn expr_inline_asm() {
+        let x;
+        asm!("mov {1}, {0}\nshl {1}, 1\nshl {0}, 2\nadd {0}, {1}",
+            inout(reg)
+            x,
+            out(reg)
+            _);
+    }
+
+    /// ExprKind::OffsetOf
+    fn expr_offset_of() {
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+        // ...
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+        { builtin # offset_of(T, field) };
+    }
+    /// ExprKind::MacCall
+    fn expr_mac_call() { "..."; "..."; "..."; }
+    /// ExprKind::Struct
+    fn expr_struct() {
+        struct Struct {}
+        let (x, base);
+        Struct {};
+        <Struct as ToOwned>::Owned {};
+        Struct { .. };
+        Struct { ..base };
+        Struct { x };
+        Struct { x, ..base };
+        Struct { x: true };
+        Struct { x: true, .. };
+        Struct { x: true, ..base };
+        Struct { 0: true, ..base };
+    }
+    /// ExprKind::Repeat
+    fn expr_repeat() { [(); 0]; }
+    /// ExprKind::Paren
+    fn expr_paren() { let expr; (expr); }
+    /// ExprKind::Try
+    fn expr_try() { let expr; expr?; }
+    /// ExprKind::Yield
+    fn expr_yield() { yield; yield true; }
+    /// ExprKind::Yeet
+    fn expr_yeet() { do yeet; do yeet 0; }
+    /// ExprKind::Become
+    fn expr_become() { become true; }
+    /// ExprKind::IncludedBytes
+    fn expr_include_bytes() {
+        b"data for include_bytes in ../expanded-exhaustive.rs\n";
+    }
+    /// ExprKind::FormatArgs
+    fn expr_format_args() {
+        let expr;
+        format_args!("");
+        format_args!("{0}", expr);
+    }
+}
+mod items {
+    /// ItemKind::ExternCrate
+    mod item_extern_crate {
+        extern crate core;
+        extern crate self as unpretty;
+        pub extern crate core as _;
+    }
+    /// ItemKind::Use
+    mod item_use {
+        use crate::{expressions, items::item_use};
+        pub use core::*;
+    }
+    /// ItemKind::Static
+    mod item_static {
+        pub static A: () = {};
+        static mut B: () = {};
+    }
+    /// ItemKind::Const
+    mod item_const {
+        pub const A: () = {};
+        trait TraitItems {
+            const B: ();
+            const C: () = {};
+        }
+    }
+    /// ItemKind::Fn
+    mod item_fn {
+        pub const unsafe extern "C" fn f() {}
+        pub async unsafe extern fn g() {}
+        fn h<'a, T>() where T: 'a {}
+        trait TraitItems {
+            unsafe extern fn f();
+        }
+        impl TraitItems for _ {
+            default unsafe extern fn f() {}
+        }
+    }
+    /// ItemKind::Mod
+    mod item_mod { }
+    /// ItemKind::ForeignMod
+    mod item_foreign_mod {
+        extern "C++" {}
+        extern {}
+    }
+    /// ItemKind::GlobalAsm
+    mod item_global_asm {
+        global_asm! (".globl my_asm_func");
+    }
+    /// ItemKind::TyAlias
+    mod item_ty_alias {
+        pub type Type<'a> where T: 'a = T;
+    }
+    /// ItemKind::Enum
+    mod item_enum {
+        pub enum Void {}
+        enum Empty { Unit, Tuple(), Struct {}, }
+        enum Generic<'a, T> where T: 'a {
+            Tuple(T),
+            Struct {
+                t: T,
+            },
+        }
+    }
+    /// ItemKind::Struct
+    mod item_struct {
+        pub struct Unit;
+        struct Tuple();
+        struct Newtype(Unit);
+        struct Struct {}
+        struct Generic<'a, T> where T: 'a {
+            t: T,
+        }
+    }
+    /// ItemKind::Union
+    mod item_union {
+        union Generic<'a, T> where T: 'a {
+            t: T,
+        }
+    }
+    /// ItemKind::Trait
+    mod item_trait {
+        pub unsafe auto trait Send {}
+        trait Trait<'a>: Sized where Self: 'a {}
+    }
+    /// ItemKind::TraitAlias
+    mod item_trait_alias {
+        pub trait Trait<T> = Sized where for<'a> T: 'a;
+    }
+    /// ItemKind::Impl
+    mod item_impl {
+        impl () {}
+        impl<T> () {}
+        impl Default for () {}
+        impl<T> const Default for () {}
+    }
+    /// ItemKind::MacCall
+    mod item_mac_call { }
+    /// ItemKind::MacroDef
+    mod item_macro_def {
+        macro_rules! mac { () => { ... }; }
+        pub macro stringify { () => {} }
+    }
+    /// ItemKind::Delegation
+    mod item_delegation {
+        /*! FIXME: todo */
+    }
+    /// ItemKind::DelegationMac
+    mod item_delegation_mac {
+        /*! FIXME: todo */
+    }
+}
+mod patterns {
+    /// PatKind::Wild
+    fn pat_wild() { let _; }
+    /// PatKind::Ident
+    fn pat_ident() {
+        let x;
+        let ref x;
+        let mut x;
+        let ref mut x;
+        let ref mut x @ _;
+    }
+    /// PatKind::Struct
+    fn pat_struct() {
+        let T {};
+        let T::<T> {};
+        let T::<'static> {};
+        let T { x };
+        let T { x: _x };
+        let T { .. };
+        let T { x, .. };
+        let T { x: _x, .. };
+        let T { 0: _x, .. };
+        let <T as ToOwned>::Owned {};
+    }
+    /// PatKind::TupleStruct
+    fn pat_tuple_struct() {
+        struct Tuple();
+        let Tuple();
+        let Tuple::<T>();
+        let Tuple::<'static>();
+        let Tuple(x);
+        let Tuple(..);
+        let Tuple(x, ..);
+    }
+    /// PatKind::Or
+    fn pat_or() { let (true | false); let (true); let (true | false); }
+    /// PatKind::Path
+    fn pat_path() {
+        let core::marker::PhantomData;
+        let core::marker::PhantomData::<T>;
+        let core::marker::PhantomData::<'static>;
+        let <T as Trait>::CONST;
+    }
+    /// PatKind::Tuple
+    fn pat_tuple() { let (); let (true,); let (true, false); }
+    /// PatKind::Box
+    fn pat_box() { let box pat; }
+    /// PatKind::Deref
+    fn pat_deref() { let deref!(pat); }
+    /// PatKind::Ref
+    fn pat_ref() { let &pat; let &mut pat; }
+    /// PatKind::Lit
+    fn pat_lit() { let 1_000_i8; let -""; }
+    /// PatKind::Range
+    fn pat_range() { let ..1; let 0..; let 0..1; let 0..=1; let -2..=-1; }
+    /// PatKind::Slice
+    fn pat_slice() { let []; let [true]; let [true]; let [true, false]; }
+    /// PatKind::Rest
+    fn pat_rest() { let ..; }
+    /// PatKind::Never
+    fn pat_never() { let !; let Some(!); }
+    /// PatKind::Paren
+    fn pat_paren() { let (pat); }
+    /// PatKind::MacCall
+    fn pat_mac_call() { let ""; let ""; let ""; }
+}
+mod statements {
+    /// StmtKind::Let
+    fn stmt_let() {
+        let _;
+        let _ = true;
+        let _: T = true;
+        let _ = true else { return; };
+    }
+    /// StmtKind::Item
+    fn stmt_item() {
+        struct Struct {}
+        struct Unit;
+    }
+    /// StmtKind::Expr
+    fn stmt_expr() { () }
+    /// StmtKind::Semi
+    fn stmt_semi() { 1 + 1; }
+    /// StmtKind::Empty
+    fn stmt_empty() { ; }
+    /// StmtKind::MacCall
+    fn stmt_mac_call() { "..."; "..."; "..."; }
+}
+mod types {
+    /// TyKind::Slice
+    fn ty_slice() { let _: [T]; }
+    /// TyKind::Array
+    fn ty_array() { let _: [T; 0]; }
+    /// TyKind::Ptr
+    fn ty_ptr() { let _: *const T; let _: *mut T; }
+    /// TyKind::Ref
+    fn ty_ref() {
+        let _: &T;
+        let _: &mut T;
+        let _: &'static T;
+        let _: &'static mut [T];
+        let _: &T<T<T<T<T>>>>;
+        let _: &T<T<T<T<T>>>>;
+    }
+    /// TyKind::BareFn
+    fn ty_bare_fn() {
+        let _: fn();
+        let _: fn() -> ();
+        let _: fn(T);
+        let _: fn(t: T);
+        let _: fn();
+        let _: for<'a> fn();
+    }
+    /// TyKind::Never
+    fn ty_never() { let _: !; }
+    /// TyKind::Tup
+    fn ty_tup() { let _: (); let _: (T,); let _: (T, T); }
+    /// TyKind::AnonStruct
+    fn ty_anon_struct() {
+        struct Struct {
+            _: struct  {
+                t: T,
+            },
+        }
+    }
+    /// TyKind::AnonUnion
+    fn ty_anon_union() {
+        struct Struct {
+            _: union  {
+                t: T,
+            },
+        }
+    }
+    /// TyKind::Path
+    fn ty_path() {
+        let _: T;
+        let _: T<'static>;
+        let _: T<T>;
+        let _: T<T>;
+        let _: T() -> !;
+        let _: <T as ToOwned>::Owned;
+    }
+    /// TyKind::TraitObject
+    fn ty_trait_object() {
+        let _: dyn Send;
+        let _: dyn Send + 'static;
+        let _: dyn 'static + Send;
+        let _: dyn for<'a> Send;
+    }
+    /// TyKind::ImplTrait
+    const fn ty_impl_trait() {
+        let _: impl Send;
+        let _: impl Send + 'static;
+        let _: impl 'static + Send;
+        let _: impl ?Sized;
+        let _: impl ~const Clone;
+        let _: impl for<'a> Send;
+    }
+    /// TyKind::Paren
+    fn ty_paren() { let _: (T); }
+    /// TyKind::Typeof
+    fn ty_typeof() {
+        /*! unused for now */
+    }
+    /// TyKind::Infer
+    fn ty_infer() { let _: _; }
+    /// TyKind::ImplicitSelf
+    fn ty_implicit_self() {
+        /*! there is no syntax for this */
+    }
+    /// TyKind::MacCall
+    fn ty_mac_call() { let _: T; let _: T; let _: T; }
+    /// TyKind::CVarArgs
+    fn ty_c_var_args() {
+        /*! FIXME: todo */
+    }
+    /// TyKind::Pat
+    fn ty_pat() { let _: u32 is 1..; }
+}
+mod visibilities {
+    /// VisibilityKind::Public
+    mod visibility_public {
+        pub struct Pub;
+    }
+    /// VisibilityKind::Restricted
+    mod visibility_restricted {
+        pub(crate) struct PubCrate;
+        pub(self) struct PubSelf;
+        pub(super) struct PubSuper;
+        pub(in crate) struct PubInCrate;
+        pub(in self) struct PubInSelf;
+        pub(in super) struct PubInSuper;
+        pub(in crate::visibilities) struct PubInCrateVisibilities;
+        pub(in self::super) struct PubInSelfSuper;
+        pub(in super::visibility_restricted) struct PubInSuperMod;
+    }
+}

tests/ui/unpretty/expanded-interpolation.rs

@@ -0,0 +1,106 @@
+//@ compile-flags: -Zunpretty=expanded
+//@ check-pass
+
+// This test covers the AST pretty-printer's insertion of parentheses in some
+// macro metavariable edge cases. Synthetic parentheses (i.e. not appearing in
+// the syntax tree) need to be printed in order for the printed code to be valid
+// Rust syntax. We also test negative cases: the pretty-printer should not be
+// synthesizing parentheses indiscriminately; only where necessary.
+
+#![feature(let_chains)]
+#![feature(if_let_guard)]
+
+macro_rules! expr {
+    ($expr:expr) => { $expr };
+}
+
+macro_rules! stmt {
+    ($stmt:stmt) => { $stmt };
+}
+
+fn if_let() {
+    macro_rules! if_let {
+        ($pat:pat, $expr:expr) => {
+            if let $pat = $expr {}
+        };
+    }
+
+    if let no_paren = true && false {}
+    if_let!(paren_around_binary, true && false);
+    if_let!(no_paren, true);
+
+    struct Struct {}
+    match () {
+        _ if let no_paren = Struct {} => {}
+    }
+}
+
+fn let_else() {
+    let no_paren = expr!(1 + 1) else { return; };
+    let paren_around_loop = expr!(loop {}) else { return; };
+}
+
+fn local() {
+    macro_rules! let_expr_minus_one {
+        ($pat:pat, $expr:expr) => {
+            let $pat = $expr - 1;
+        };
+    }
+
+    let void;
+    let_expr_minus_one!(no_paren, match void {});
+
+    macro_rules! let_expr_else_return {
+        ($pat:pat, $expr:expr) => {
+            let $pat = $expr else { return; };
+        };
+    }
+
+    let_expr_else_return!(no_paren, void());
+}
+
+fn match_arm() {
+    macro_rules! match_arm {
+        ($pat:pat, $expr:expr) => {
+            match () { $pat => $expr }
+        };
+    }
+
+    match_arm!(no_paren, 1 - 1);
+    match_arm!(paren_around_brace, { 1 } - 1);
+}
+
+/// https://github.com/rust-lang/rust/issues/98790
+fn stmt_boundary() {
+    macro_rules! expr_as_stmt {
+        ($expr:expr) => {
+            stmt!($expr)
+        };
+    }
+
+    let paren_around_match;
+    expr_as_stmt!(match paren_around_match {} | true);
+
+    macro_rules! minus_one {
+        ($expr:expr) => {
+            expr_as_stmt!($expr - 1)
+        };
+    }
+
+    let (no_paren, paren_around_loop);
+    minus_one!(no_paren);
+    minus_one!(match paren_around_match {});
+    minus_one!(match paren_around_match {}());
+    minus_one!(match paren_around_match {}[0]);
+    minus_one!(loop { break paren_around_loop; });
+}
+
+fn vis_inherited() {
+    macro_rules! vis_inherited {
+        ($vis:vis struct) => {
+            $vis struct Struct;
+        };
+    }
+
+    vis_inherited!(struct);
+}

tests/ui/unpretty/expanded-interpolation.stdout

@@ -0,0 +1,92 @@
+#![feature(prelude_import)]
+#![no_std]
+//@ compile-flags: -Zunpretty=expanded
+//@ check-pass
+
+// This test covers the AST pretty-printer's insertion of parentheses in some
+// macro metavariable edge cases. Synthetic parentheses (i.e. not appearing in
+// the syntax tree) need to be printed in order for the printed code to be valid
+// Rust syntax. We also test negative cases: the pretty-printer should not be
+// synthesizing parentheses indiscriminately; only where necessary.
+
+#![feature(let_chains)]
+#![feature(if_let_guard)]
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+
+macro_rules! expr { ($expr:expr) => { $expr }; }
+
+macro_rules! stmt { ($stmt:stmt) => { $stmt }; }
+
+fn if_let() {
+    macro_rules! if_let {
+        ($pat:pat, $expr:expr) => { if let $pat = $expr {} };
+    }
+
+    if let no_paren = true && false {}
+    if let paren_around_binary = (true && false) {};
+    if let no_paren = true {};
+
+    struct Struct {}
+    match () { _ if let no_paren = Struct {} => {} }
+}
+
+fn let_else() {
+    let no_paren = 1 + 1 else { return; };
+    let paren_around_loop = (loop {}) else { return; };
+}
+
+fn local() {
+    macro_rules! let_expr_minus_one {
+        ($pat:pat, $expr:expr) => { let $pat = $expr - 1; };
+    }
+
+    let void;
+    let no_paren = match void {} - 1;
+
+    macro_rules! let_expr_else_return {
+        ($pat:pat, $expr:expr) => { let $pat = $expr else { return; }; };
+    }
+    let 
+
+            no_paren = void() else { return; };
+}
+
+fn match_arm() {
+    macro_rules! match_arm {
+        ($pat:pat, $expr:expr) => { match () { $pat => $expr } };
+    }
+    match () {
+
+
+            no_paren => 1 - 1,
+    };
+    match () { paren_around_brace => ({ 1 }) - 1, };
+}
+
+/// https://github.com/rust-lang/rust/issues/98790
+fn stmt_boundary() {
+    macro_rules! expr_as_stmt { ($expr:expr) => { stmt!($expr) }; }
+
+    let paren_around_match;
+    (match paren_around_match {}) | true;
+
+    macro_rules! minus_one { ($expr:expr) => { expr_as_stmt!($expr - 1) }; }
+
+    let (no_paren, paren_around_loop);
+    no_paren - 1;
+    (match paren_around_match {}) - 1;
+    (match paren_around_match {})() - 1;
+    (match paren_around_match {})[0] - 1;
+    (loop { break paren_around_loop; }) - 1;
+}
+
+fn vis_inherited() {
+    macro_rules! vis_inherited {
+        ($vis:vis struct) => { $vis struct Struct; };
+    }
+    struct Struct;
+
+}

tests/ui/unpretty/let-else.rs

@@ -1,11 +0,0 @@
-//@ compile-flags: -Zunpretty=expanded
-//@ check-pass
-
-macro_rules! expr {
-    ($e:expr) => { $e };
-}
-
-fn main() {
-    let _ = expr!(1 + 1) else { return; };
-    let _ = expr!(loop {}) else { return; };
-}

tests/ui/unpretty/let-else.stdout

@@ -1,15 +0,0 @@
-#![feature(prelude_import)]
-#![no_std]
-#[prelude_import]
-use ::std::prelude::rust_2015::*;
-#[macro_use]
-extern crate std;
-//@ compile-flags: -Zunpretty=expanded
-//@ check-pass
-
-macro_rules! expr { ($e:expr) => { $e }; }
-
-fn main() {
-    let _ = 1 + 1 else { return; };
-    let _ = (loop {}) else { return; };
-}