Skip to content

Commit

Permalink
Auto merge of #119212 - w-utter:pretty-print-const-expr, r=compiler-e…
Browse files Browse the repository at this point in the history
…rrors

Fix representation when printing abstract consts

Previously, when printing a const generic expr, it would only display it as `{{const expr}}`. This allows for a more legible representation when printing these out.

I also zipped the types with their constants for abstract consts that contain function calls when using type annotations, eg: `foo(S: usize, true: bool) -> usize` insteaad of `foo(S, true): fn(usize, bool) -> usize` for conciseness.
  • Loading branch information
bors committed Mar 19, 2024
2 parents 91b87c4 + 7c4b07d commit 8579a18
Show file tree
Hide file tree
Showing 4 changed files with 160 additions and 12 deletions.
154 changes: 152 additions & 2 deletions compiler/rustc_middle/src/ty/print/pretty.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use crate::query::Providers;
use crate::traits::util::{super_predicates_for_pretty_printing, supertraits_for_pretty_printing};
use crate::ty::GenericArgKind;
use crate::ty::{
ConstInt, ParamConst, ScalarInt, Term, TermKind, TypeFoldable, TypeSuperFoldable,
ConstInt, Expr, ParamConst, ScalarInt, Term, TermKind, TypeFoldable, TypeSuperFoldable,
TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
};
use rustc_apfloat::ieee::{Double, Single};
Expand Down Expand Up @@ -270,6 +270,31 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
Ok(())
}

/// Prints `(...)` around what `f` prints.
fn parenthesized(
&mut self,
f: impl FnOnce(&mut Self) -> Result<(), PrintError>,
) -> Result<(), PrintError> {
self.write_str("(")?;
f(self)?;
self.write_str(")")?;
Ok(())
}

/// Prints `(...)` around what `f` prints if `parenthesized` is true, otherwise just prints `f`.
fn maybe_parenthesized(
&mut self,
f: impl FnOnce(&mut Self) -> Result<(), PrintError>,
parenthesized: bool,
) -> Result<(), PrintError> {
if parenthesized {
self.parenthesized(f)?;
} else {
f(self)?;
}
Ok(())
}

/// Prints `<...>` around what `f` prints.
fn generic_delimiters(
&mut self,
Expand Down Expand Up @@ -1490,12 +1515,137 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
ty::ConstKind::Placeholder(placeholder) => p!(write("{placeholder:?}")),
// FIXME(generic_const_exprs):
// write out some legible representation of an abstract const?
ty::ConstKind::Expr(_) => p!("{{const expr}}"),
ty::ConstKind::Expr(expr) => self.pretty_print_const_expr(expr, print_ty)?,
ty::ConstKind::Error(_) => p!("{{const error}}"),
};
Ok(())
}

fn pretty_print_const_expr(
&mut self,
expr: Expr<'tcx>,
print_ty: bool,
) -> Result<(), PrintError> {
define_scoped_cx!(self);
match expr {
Expr::Binop(op, c1, c2) => {
let precedence = |binop: rustc_middle::mir::BinOp| {
use rustc_ast::util::parser::AssocOp;
AssocOp::from_ast_binop(binop.to_hir_binop().into()).precedence()
};
let op_precedence = precedence(op);
let formatted_op = op.to_hir_binop().as_str();
let (lhs_parenthesized, rhs_parenthesized) = match (c1.kind(), c2.kind()) {
(
ty::ConstKind::Expr(Expr::Binop(lhs_op, _, _)),
ty::ConstKind::Expr(Expr::Binop(rhs_op, _, _)),
) => (precedence(lhs_op) < op_precedence, precedence(rhs_op) < op_precedence),
(ty::ConstKind::Expr(Expr::Binop(lhs_op, ..)), ty::ConstKind::Expr(_)) => {
(precedence(lhs_op) < op_precedence, true)
}
(ty::ConstKind::Expr(_), ty::ConstKind::Expr(Expr::Binop(rhs_op, ..))) => {
(true, precedence(rhs_op) < op_precedence)
}
(ty::ConstKind::Expr(_), ty::ConstKind::Expr(_)) => (true, true),
(ty::ConstKind::Expr(Expr::Binop(lhs_op, ..)), _) => {
(precedence(lhs_op) < op_precedence, false)
}
(_, ty::ConstKind::Expr(Expr::Binop(rhs_op, ..))) => {
(false, precedence(rhs_op) < op_precedence)
}
(ty::ConstKind::Expr(_), _) => (true, false),
(_, ty::ConstKind::Expr(_)) => (false, true),
_ => (false, false),
};

self.maybe_parenthesized(
|this| this.pretty_print_const(c1, print_ty),
lhs_parenthesized,
)?;
p!(write(" {formatted_op} "));
self.maybe_parenthesized(
|this| this.pretty_print_const(c2, print_ty),
rhs_parenthesized,
)?;
}
Expr::UnOp(op, ct) => {
use rustc_middle::mir::UnOp;
let formatted_op = match op {
UnOp::Not => "!",
UnOp::Neg => "-",
};
let parenthesized = match ct.kind() {
ty::ConstKind::Expr(Expr::UnOp(c_op, ..)) => c_op != op,
ty::ConstKind::Expr(_) => true,
_ => false,
};
p!(write("{formatted_op}"));
self.maybe_parenthesized(
|this| this.pretty_print_const(ct, print_ty),
parenthesized,
)?
}
Expr::FunctionCall(fn_def, fn_args) => {
use ty::TyKind;
match fn_def.ty().kind() {
TyKind::FnDef(def_id, gen_args) => {
p!(print_value_path(*def_id, gen_args), "(");
if print_ty {
let tcx = self.tcx();
let sig = tcx.fn_sig(def_id).instantiate(tcx, gen_args).skip_binder();

let mut args_with_ty = fn_args.iter().map(|ct| (ct, ct.ty()));
let output_ty = sig.output();

if let Some((ct, ty)) = args_with_ty.next() {
self.typed_value(
|this| this.pretty_print_const(ct, print_ty),
|this| this.pretty_print_type(ty),
": ",
)?;
for (ct, ty) in args_with_ty {
p!(", ");
self.typed_value(
|this| this.pretty_print_const(ct, print_ty),
|this| this.pretty_print_type(ty),
": ",
)?;
}
}
p!(write(") -> {output_ty}"));
} else {
p!(comma_sep(fn_args.iter()), ")");
}
}
_ => bug!("unexpected type of fn def"),
}
}
Expr::Cast(kind, ct, ty) => {
use ty::abstract_const::CastKind;
if kind == CastKind::As || (kind == CastKind::Use && self.should_print_verbose()) {
let parenthesized = match ct.kind() {
ty::ConstKind::Expr(Expr::Cast(_, _, _)) => false,
ty::ConstKind::Expr(_) => true,
_ => false,
};
self.maybe_parenthesized(
|this| {
this.typed_value(
|this| this.pretty_print_const(ct, print_ty),
|this| this.pretty_print_type(ty),
" as ",
)
},
parenthesized,
)?;
} else {
self.pretty_print_const(ct, print_ty)?
}
}
}
Ok(())
}

fn pretty_print_const_scalar(
&mut self,
scalar: Scalar,
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@ where
//~^^ ERROR: unconstrained generic constant
//~^^^ ERROR: function takes 1 generic argument but 2 generic arguments were supplied
//~^^^^ ERROR: unconstrained generic constant
//~^^^^^ ERROR: unconstrained generic constant `{const expr}`
//~^^^^^^ ERROR: unconstrained generic constant `{const expr}`
//~^^^^^ ERROR: unconstrained generic constant `L + 1 + L`
//~^^^^^^ ERROR: unconstrained generic constant `L + 1`
}

fn main() {}
Original file line number Diff line number Diff line change
Expand Up @@ -52,19 +52,17 @@ LL | | }
LL | | }],
| |_____^ required by this bound in `foo`

error: unconstrained generic constant `{const expr}`
error: unconstrained generic constant `L + 1 + L`
--> $DIR/issue_114151.rs:17:5
|
LL | foo::<_, L>([(); L + 1 + L]);
| ^^^^^^^^^^^

error: unconstrained generic constant `{const expr}`
error: unconstrained generic constant `L + 1`
--> $DIR/issue_114151.rs:17:5
|
LL | foo::<_, L>([(); L + 1 + L]);
| ^^^^^^^^^^^
|
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

error: aborting due to 6 previous errors

Expand Down
8 changes: 4 additions & 4 deletions tests/ui/const-generics/transmute-fail.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
LL | std::mem::transmute(v)
| ^^^^^^^^^^^^^^^^^^^
|
= note: source type: `[[u32; H+1]; W]` (generic size {const expr})
= note: target type: `[[u32; W+1]; H]` (generic size {const expr})
= note: source type: `[[u32; H+1]; W]` (generic size (H + 1) * 4 * W)
= note: target type: `[[u32; W+1]; H]` (generic size (W + 1) * 4 * H)

error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
--> $DIR/transmute-fail.rs:16:5
Expand All @@ -22,8 +22,8 @@ error[E0512]: cannot transmute between types of different sizes, or dependently-
LL | std::mem::transmute(v)
| ^^^^^^^^^^^^^^^^^^^
|
= note: source type: `[[u32; H]; W]` (generic size {const expr})
= note: target type: `[u32; W * H * H]` (generic size {const expr})
= note: source type: `[[u32; H]; W]` (generic size 4 * H * W)
= note: target type: `[u32; W * H * H]` (generic size 4 * H * H * W)

error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
--> $DIR/transmute-fail.rs:30:5
Expand Down

0 comments on commit 8579a18

Please sign in to comment.