From 226edf64fa58e591d8abc6afef5e38c15c181698 Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote 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 cbe75b3dab6..81055431f64 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 1411f61744d..53339ce7e28 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 894ec8341f8..5a8bbaf8ec1 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 c1d68d8cda9..ea7cf7c4f64 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 7d817da1362..260462cfeef 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 --> $DIR/key-value-expansion-on-mac.rs:11:17 | LL | #[rustc_dummy = stringify!(b)] diff --git a/tests/ui/attributes/key-value-expansion.rs b/tests/ui/attributes/key-value-expansion.rs index 83d601e5e3a..3065c12749c 100644 --- a/tests/ui/attributes/key-value-expansion.rs +++ b/tests/ui/attributes/key-value-expansion.rs @@ -18,13 +18,13 @@ macro_rules! bug { // Any expressions containing macro call `X` that's more complex than `X` itself. // Parentheses will work. -bug!((column!())); //~ ERROR unexpected expression: `(7u32)` +bug!((column!())); //~ ERROR attribute value must be a literal // Original test case. macro_rules! bug { () => { - bug!("bug" + stringify!(found)); //~ ERROR unexpected expression: `"bug" + "found"` + bug!("bug" + stringify!(found)); //~ ERROR attribute value must be a literal }; ($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 aaa8b169583..54d79c5bebb 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 70dcd5413f1..fda0a5d6a3f 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 92a8f585821..84130965d31 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 e5bcecce6ee..0e61c65305f 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 71b8d21fb4d..0b332840042 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 0d84e723fc3..0d801ebd3ac 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 c24d9f15388..92e99b7a70b 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 8cb9ef7e0c9..c614f493885 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 756f99ab12c..b5dacdf7d0d 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 f49476c4408..fd0916b4411 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 fa20b5f8b16..040c63a5fbf 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