From 226edf64fa58e591d8abc6afef5e38c15c181698 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Tue, 12 Dec 2023 09:55:50 +1100
Subject: [PATCH] Improve an error involving attribute values.
Attribute values must be literals. The error you get when that doesn't
hold is pretty bad, e.g.:
```
unexpected expression: 1 + 1
```
You also get the same error if the attribute value is a literal, but an
invalid literal, e.g.:
```
unexpected expression: "foo"suffix
```
This commit does two things.
- Changes the error message to "attribute value must be a literal",
which gives a better idea of what the problem is and how to fix it. It
also no longer prints the invalid expression, because the carets below
highlight it anyway.
- Separates the "not a literal" case from the "invalid literal" case.
Which means invalid literals now get the specific error at the literal
level, rather than at the attribute level.
---
compiler/rustc_parse/src/validate_attr.rs | 60 ++++++++++++-------
tests/ui/attributes/issue-90873.rs | 4 +-
tests/ui/attributes/issue-90873.stderr | 9 +--
.../attributes/key-value-expansion-on-mac.rs | 4 +-
.../key-value-expansion-on-mac.stderr | 2 +-
tests/ui/attributes/key-value-expansion.rs | 6 +-
.../ui/attributes/key-value-expansion.stderr | 6 +-
tests/ui/attributes/unused-item-in-attr.rs | 2 +-
.../ui/attributes/unused-item-in-attr.stderr | 4 +-
tests/ui/consts/issue-90878-2.rs | 2 +-
tests/ui/consts/issue-90878-2.stderr | 2 +-
tests/ui/malformed/malformed-interpolated.rs | 4 +-
.../malformed/malformed-interpolated.stderr | 4 +-
tests/ui/parser/bad-lit-suffixes.rs | 5 +-
tests/ui/parser/bad-lit-suffixes.stderr | 27 ++++++---
tests/ui/parser/issues/issue-104620.rs | 2 +-
tests/ui/parser/issues/issue-104620.stderr | 6 +-
17 files changed, 87 insertions(+), 62 deletions(-)
diff --git a/compiler/rustc_parse/src/validate_attr.rs b/compiler/rustc_parse/src/validate_attr.rs
index cbe75b3dab6ee..81055431f649d 100644
--- a/compiler/rustc_parse/src/validate_attr.rs
+++ b/compiler/rustc_parse/src/validate_attr.rs
@@ -6,9 +6,9 @@ use rustc_ast::token::Delimiter;
use rustc_ast::tokenstream::DelimSpan;
use rustc_ast::MetaItemKind;
use rustc_ast::{self as ast, AttrArgs, AttrArgsEq, Attribute, DelimArgs, MetaItem};
-use rustc_ast_pretty::pprust;
use rustc_errors::{Applicability, FatalError, PResult};
use rustc_feature::{AttributeTemplate, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
+use rustc_session::errors::report_lit_error;
use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
use rustc_session::parse::ParseSess;
use rustc_span::{sym, Span, Symbol};
@@ -51,28 +51,44 @@ pub fn parse_meta<'a>(sess: &'a ParseSess, attr: &Attribute) -> PResult<'a, Meta
MetaItemKind::List(nmis)
}
AttrArgs::Eq(_, AttrArgsEq::Ast(expr)) => {
- if let ast::ExprKind::Lit(token_lit) = expr.kind
- && let Ok(lit) = ast::MetaItemLit::from_token_lit(token_lit, expr.span)
- {
- if token_lit.suffix.is_some() {
- let mut err = sess.span_diagnostic.struct_span_err(
- expr.span,
- "suffixed literals are not allowed in attributes",
- );
- err.help(
- "instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), \
- use an unsuffixed version (`1`, `1.0`, etc.)",
- );
- return Err(err);
- } else {
- MetaItemKind::NameValue(lit)
- }
+ if let ast::ExprKind::Lit(token_lit) = expr.kind {
+ let res = ast::MetaItemLit::from_token_lit(token_lit, expr.span);
+ let res = match res {
+ Ok(lit) => {
+ if token_lit.suffix.is_some() {
+ let mut err = sess.span_diagnostic.struct_span_err(
+ expr.span,
+ "suffixed literals are not allowed in attributes",
+ );
+ err.help(
+ "instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), \
+ use an unsuffixed version (`1`, `1.0`, etc.)",
+ );
+ return Err(err);
+ } else {
+ MetaItemKind::NameValue(lit)
+ }
+ }
+ Err(err) => {
+ report_lit_error(sess, err, token_lit, expr.span);
+ let lit = ast::MetaItemLit {
+ symbol: token_lit.symbol,
+ suffix: token_lit.suffix,
+ kind: ast::LitKind::Err,
+ span: expr.span,
+ };
+ MetaItemKind::NameValue(lit)
+ }
+ };
+ res
} else {
- // The non-error case can happen with e.g. `#[foo = 1+1]`. The error case can
- // happen with e.g. `#[foo = include_str!("nonexistent-file.rs")]`; in that
- // case we delay the error because an earlier error will have already been
- // reported.
- let msg = format!("unexpected expression: `{}`", pprust::expr_to_string(expr));
+ // Example cases:
+ // - `#[foo = 1+1]`: results in `ast::ExprKind::BinOp`.
+ // - `#[foo = include_str!("nonexistent-file.rs")]`:
+ // results in `ast::ExprKind::Err`. In that case we delay
+ // the error because an earlier error will have already
+ // been reported.
+ let msg = format!("attribute value must be a literal");
let mut err = sess.span_diagnostic.struct_span_err(expr.span, msg);
if let ast::ExprKind::Err = expr.kind {
err.downgrade_to_delayed_bug();
diff --git a/tests/ui/attributes/issue-90873.rs b/tests/ui/attributes/issue-90873.rs
index 1411f61744d25..53339ce7e28fb 100644
--- a/tests/ui/attributes/issue-90873.rs
+++ b/tests/ui/attributes/issue-90873.rs
@@ -1,9 +1,9 @@
#![u=||{static d=||1;}]
-//~^ unexpected expression
+//~^ attribute value must be a literal
//~| cannot find attribute `u` in this scope
//~| missing type for `static` item
#![a={impl std::ops::Neg for i8 {}}]
-//~^ ERROR unexpected expression
+//~^ ERROR attribute value must be a literal
//~| ERROR cannot find attribute `a` in this scope
//~| ERROR `main` function not found in crate `issue_90873`
diff --git a/tests/ui/attributes/issue-90873.stderr b/tests/ui/attributes/issue-90873.stderr
index 894ec8341f8e0..5a8bbaf8ec191 100644
--- a/tests/ui/attributes/issue-90873.stderr
+++ b/tests/ui/attributes/issue-90873.stderr
@@ -1,15 +1,10 @@
-error: unexpected expression: `||
- {
- static d: _ = || 1;
- }`
+error: attribute value must be a literal
--> $DIR/issue-90873.rs:1:6
|
LL | #![u=||{static d=||1;}]
| ^^^^^^^^^^^^^^^^^
-error: unexpected expression: `{
- impl std::ops::Neg for i8 {}
- }`
+error: attribute value must be a literal
--> $DIR/issue-90873.rs:6:6
|
LL | #![a={impl std::ops::Neg for i8 {}}]
diff --git a/tests/ui/attributes/key-value-expansion-on-mac.rs b/tests/ui/attributes/key-value-expansion-on-mac.rs
index c1d68d8cda9e7..ea7cf7c4f640f 100644
--- a/tests/ui/attributes/key-value-expansion-on-mac.rs
+++ b/tests/ui/attributes/key-value-expansion-on-mac.rs
@@ -7,8 +7,8 @@ macro_rules! bar {
// FIXME?: `bar` here expands before `stringify` has a chance to expand.
// `#[rustc_dummy = ...]` is validated and dropped during expansion of `bar`,
-// the "unexpected expression" errors comes from the validation.
-#[rustc_dummy = stringify!(b)] //~ ERROR unexpected expression: `stringify!(b)`
+// the "attribute value must be a literal" error comes from the validation.
+#[rustc_dummy = stringify!(b)] //~ ERROR attribute value must be a literal
bar!();
fn main() {}
diff --git a/tests/ui/attributes/key-value-expansion-on-mac.stderr b/tests/ui/attributes/key-value-expansion-on-mac.stderr
index 7d817da13626d..260462cfeefac 100644
--- a/tests/ui/attributes/key-value-expansion-on-mac.stderr
+++ b/tests/ui/attributes/key-value-expansion-on-mac.stderr
@@ -1,4 +1,4 @@
-error: unexpected expression: `stringify!(b)`
+error: attribute value must be a literal
--> $DIR/key-value-expansion-on-mac.rs:11:17
|
LL | #[rustc_dummy = stringify!(b)]
diff --git a/tests/ui/attributes/key-value-expansion.rs b/tests/ui/attributes/key-value-expansion.rs
index 83d601e5e3a79..3065c12749c2c 100644
--- a/tests/ui/attributes/key-value-expansion.rs
+++ b/tests/ui/attributes/key-value-expansion.rs
@@ -18,13 +18,13 @@ macro_rules! bug {
// Any expressions containing macro call `X` that's more complex than `X` itself.
// Parentheses will work.
-bug!((column!())); //~ ERROR unexpected expression: `(7u32)`
+bug!((column!())); //~ ERROR attribute value must be a literal
// Original test case.
macro_rules! bug {
() => {
- bug!("bug" + stringify!(found)); //~ ERROR unexpected expression: `"bug" + "found"`
+ bug!("bug" + stringify!(found)); //~ ERROR attribute value must be a literal
};
($test:expr) => {
#[doc = $test]
@@ -46,7 +46,7 @@ macro_rules! doc_comment {
macro_rules! some_macro {
($t1: ty) => {
doc_comment! {format!("{coor}", coor = stringify!($t1)).as_str()}
- //~^ ERROR unexpected expression: `{
+ //~^ ERROR attribute value must be a literal
};
}
diff --git a/tests/ui/attributes/key-value-expansion.stderr b/tests/ui/attributes/key-value-expansion.stderr
index aaa8b169583fd..54d79c5bebb7f 100644
--- a/tests/ui/attributes/key-value-expansion.stderr
+++ b/tests/ui/attributes/key-value-expansion.stderr
@@ -1,10 +1,10 @@
-error: unexpected expression: `(7u32)`
+error: attribute value must be a literal
--> $DIR/key-value-expansion.rs:21:6
|
LL | bug!((column!()));
| ^^^^^^^^^^^
-error: unexpected expression: `"bug" + "found"`
+error: attribute value must be a literal
--> $DIR/key-value-expansion.rs:27:14
|
LL | bug!("bug" + stringify!(found));
@@ -15,7 +15,7 @@ LL | bug!();
|
= note: this error originates in the macro `bug` (in Nightly builds, run with -Z macro-backtrace for more info)
-error: unexpected expression: `{ let res = ::alloc::fmt::format(format_args!("{0}", "u8")); res }.as_str()`
+error: attribute value must be a literal
--> $DIR/key-value-expansion.rs:48:23
|
LL | doc_comment! {format!("{coor}", coor = stringify!($t1)).as_str()}
diff --git a/tests/ui/attributes/unused-item-in-attr.rs b/tests/ui/attributes/unused-item-in-attr.rs
index 70dcd5413f1ee..fda0a5d6a3f16 100644
--- a/tests/ui/attributes/unused-item-in-attr.rs
+++ b/tests/ui/attributes/unused-item-in-attr.rs
@@ -1,5 +1,5 @@
#[w = { extern crate alloc; }]
-//~^ ERROR unexpected expression: `{
+//~^ ERROR attribute value must be a literal
//~| ERROR cannot find attribute `w` in this scope
fn f() {}
diff --git a/tests/ui/attributes/unused-item-in-attr.stderr b/tests/ui/attributes/unused-item-in-attr.stderr
index 92a8f58582136..84130965d31cf 100644
--- a/tests/ui/attributes/unused-item-in-attr.stderr
+++ b/tests/ui/attributes/unused-item-in-attr.stderr
@@ -1,6 +1,4 @@
-error: unexpected expression: `{
- extern crate alloc;
- }`
+error: attribute value must be a literal
--> $DIR/unused-item-in-attr.rs:1:7
|
LL | #[w = { extern crate alloc; }]
diff --git a/tests/ui/consts/issue-90878-2.rs b/tests/ui/consts/issue-90878-2.rs
index e5bcecce6ee8f..0e61c65305fbe 100644
--- a/tests/ui/consts/issue-90878-2.rs
+++ b/tests/ui/consts/issue-90878-2.rs
@@ -1,4 +1,4 @@
- #![l=|x|[b;x ]] //~ ERROR unexpected expression: `|x| [b; x]`
+ #![l=|x|[b;x ]] //~ ERROR attribute value must be a literal
//~^ ERROR cannot find attribute `l` in this scope
// notice the space at the start,
diff --git a/tests/ui/consts/issue-90878-2.stderr b/tests/ui/consts/issue-90878-2.stderr
index 71b8d21fb4dc2..0b332840042ef 100644
--- a/tests/ui/consts/issue-90878-2.stderr
+++ b/tests/ui/consts/issue-90878-2.stderr
@@ -1,4 +1,4 @@
-error: unexpected expression: `|x| [b; x]`
+error: attribute value must be a literal
--> $DIR/issue-90878-2.rs:1:7
|
LL | #![l=|x|[b;x ]]
diff --git a/tests/ui/malformed/malformed-interpolated.rs b/tests/ui/malformed/malformed-interpolated.rs
index 0d84e723fc3dd..0d801ebd3ac9a 100644
--- a/tests/ui/malformed/malformed-interpolated.rs
+++ b/tests/ui/malformed/malformed-interpolated.rs
@@ -10,7 +10,7 @@ macro_rules! check {
check!("0"); // OK
check!(0); // OK
check!(0u8); //~ ERROR suffixed literals are not allowed in attributes
-check!(-0); //~ ERROR unexpected expression: `-0`
-check!(0 + 0); //~ ERROR unexpected expression: `0 + 0`
+check!(-0); //~ ERROR attribute value must be a literal
+check!(0 + 0); //~ ERROR attribute value must be a literal
fn main() {}
diff --git a/tests/ui/malformed/malformed-interpolated.stderr b/tests/ui/malformed/malformed-interpolated.stderr
index c24d9f15388fc..92e99b7a70b34 100644
--- a/tests/ui/malformed/malformed-interpolated.stderr
+++ b/tests/ui/malformed/malformed-interpolated.stderr
@@ -6,13 +6,13 @@ LL | check!(0u8);
|
= help: instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), use an unsuffixed version (`1`, `1.0`, etc.)
-error: unexpected expression: `-0`
+error: attribute value must be a literal
--> $DIR/malformed-interpolated.rs:13:8
|
LL | check!(-0);
| ^^
-error: unexpected expression: `0 + 0`
+error: attribute value must be a literal
--> $DIR/malformed-interpolated.rs:14:8
|
LL | check!(0 + 0);
diff --git a/tests/ui/parser/bad-lit-suffixes.rs b/tests/ui/parser/bad-lit-suffixes.rs
index 8cb9ef7e0c921..c614f49388574 100644
--- a/tests/ui/parser/bad-lit-suffixes.rs
+++ b/tests/ui/parser/bad-lit-suffixes.rs
@@ -28,11 +28,12 @@ fn main() {
}
#[rustc_dummy = "string"suffix]
-//~^ ERROR unexpected expression: `"string"suffix`
+//~^ ERROR suffixes on string literals are invalid
fn f() {}
#[must_use = "string"suffix]
-//~^ ERROR unexpected expression: `"string"suffix`
+//~^ ERROR suffixes on string literals are invalid
+//~| ERROR malformed `must_use` attribute input
fn g() {}
#[link(name = "string"suffix)]
diff --git a/tests/ui/parser/bad-lit-suffixes.stderr b/tests/ui/parser/bad-lit-suffixes.stderr
index 756f99ab12c82..b5dacdf7d0d3d 100644
--- a/tests/ui/parser/bad-lit-suffixes.stderr
+++ b/tests/ui/parser/bad-lit-suffixes.stderr
@@ -10,26 +10,39 @@ error: suffixes on string literals are invalid
LL | "C"suffix
| ^^^^^^^^^ invalid suffix `suffix`
-error: unexpected expression: `"string"suffix`
+error: suffixes on string literals are invalid
--> $DIR/bad-lit-suffixes.rs:30:17
|
LL | #[rustc_dummy = "string"suffix]
- | ^^^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^ invalid suffix `suffix`
-error: unexpected expression: `"string"suffix`
+error: suffixes on string literals are invalid
--> $DIR/bad-lit-suffixes.rs:34:14
|
LL | #[must_use = "string"suffix]
- | ^^^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^ invalid suffix `suffix`
+
+error: malformed `must_use` attribute input
+ --> $DIR/bad-lit-suffixes.rs:34:1
+ |
+LL | #[must_use = "string"suffix]
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+help: the following are the possible correct uses
+ |
+LL | #[must_use = "reason"]
+ |
+LL | #[must_use]
+ |
error: suffixes on string literals are invalid
- --> $DIR/bad-lit-suffixes.rs:38:15
+ --> $DIR/bad-lit-suffixes.rs:39:15
|
LL | #[link(name = "string"suffix)]
| ^^^^^^^^^^^^^^ invalid suffix `suffix`
error: invalid suffix `suffix` for number literal
- --> $DIR/bad-lit-suffixes.rs:42:41
+ --> $DIR/bad-lit-suffixes.rs:43:41
|
LL | #[rustc_layout_scalar_valid_range_start(0suffix)]
| ^^^^^^^ invalid suffix `suffix`
@@ -136,5 +149,5 @@ LL | 1.0e10suffix;
|
= help: valid suffixes are `f32` and `f64`
-error: aborting due to 20 previous errors
+error: aborting due to 21 previous errors
diff --git a/tests/ui/parser/issues/issue-104620.rs b/tests/ui/parser/issues/issue-104620.rs
index f49476c44084c..fd0916b44110a 100644
--- a/tests/ui/parser/issues/issue-104620.rs
+++ b/tests/ui/parser/issues/issue-104620.rs
@@ -1,4 +1,4 @@
#![feature(rustc_attrs)]
-#![rustc_dummy=5z] //~ ERROR unexpected expression: `5z`
+#![rustc_dummy=5z] //~ ERROR invalid suffix `z` for number literal
fn main() {}
diff --git a/tests/ui/parser/issues/issue-104620.stderr b/tests/ui/parser/issues/issue-104620.stderr
index fa20b5f8b1625..040c63a5fbfbf 100644
--- a/tests/ui/parser/issues/issue-104620.stderr
+++ b/tests/ui/parser/issues/issue-104620.stderr
@@ -1,8 +1,10 @@
-error: unexpected expression: `5z`
+error: invalid suffix `z` for number literal
--> $DIR/issue-104620.rs:3:16
|
LL | #![rustc_dummy=5z]
- | ^^
+ | ^^ invalid suffix `z`
+ |
+ = help: the suffix must be one of the numeric types (`u32`, `isize`, `f32`, etc.)
error: aborting due to 1 previous error