Improve diagnostics for `concat_bytes!` with C string literals
Use the same error as other invalid types for `concat_bytes!`, rather
than using `ConcatCStrLit` from `concat!`. Also add more information
with a note about why this doesn't work, and a suggestion to use a
null-terminated byte string instead.
diff --git a/compiler/rustc_builtin_macros/messages.ftl b/compiler/rustc_builtin_macros/messages.ftl
index d32e6f1..c5d1f2a 100644
--- a/compiler/rustc_builtin_macros/messages.ftl
+++ b/compiler/rustc_builtin_macros/messages.ftl
@@ -104,6 +104,8 @@
builtin_macros_concat_bytes_invalid = cannot concatenate {$lit_kind} literals
.byte_char = try using a byte character
.byte_str = try using a byte string
+ .c_str = try using a null-terminated byte string
+ .c_str_note = concatenating C strings is ambiguous about including the '\0'
.number_array = try wrapping the number in an array
builtin_macros_concat_bytes_missing_literal = expected a byte literal
diff --git a/compiler/rustc_builtin_macros/src/concat_bytes.rs b/compiler/rustc_builtin_macros/src/concat_bytes.rs
index 456f2b9..92d011f 100644
--- a/compiler/rustc_builtin_macros/src/concat_bytes.rs
+++ b/compiler/rustc_builtin_macros/src/concat_bytes.rs
@@ -1,6 +1,6 @@
use rustc_ast::ptr::P;
use rustc_ast::tokenstream::TokenStream;
-use rustc_ast::{ExprKind, LitIntType, LitKind, UintTy, token};
+use rustc_ast::{ExprKind, LitIntType, LitKind, StrStyle, UintTy, token};
use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt, MacEager, MacroExpanderResult};
use rustc_session::errors::report_lit_error;
use rustc_span::{ErrorGuaranteed, Span};
@@ -21,15 +21,32 @@ fn invalid_type_err(
let snippet = cx.sess.source_map().span_to_snippet(span).ok();
let dcx = cx.dcx();
match LitKind::from_token_lit(token_lit) {
- Ok(LitKind::CStr(_, _)) => {
+ Ok(LitKind::CStr(_, style)) => {
// Avoid ambiguity in handling of terminal `NUL` by refusing to
// concatenate C string literals as bytes.
- dcx.emit_err(errors::ConcatCStrLit { span })
+ let sugg = if let Some(mut as_bstr) = snippet
+ && style == StrStyle::Cooked
+ && as_bstr.starts_with('c')
+ && as_bstr.ends_with('"')
+ {
+ // Suggest`c"foo"` -> `b"foo\0"` if we can
+ as_bstr.replace_range(0..1, "b");
+ as_bstr.pop();
+ as_bstr.push_str(r#"\0""#);
+ Some(ConcatBytesInvalidSuggestion::CStrLit { span, as_bstr })
+ } else {
+ // No suggestion for a missing snippet, raw strings, or if for some reason we have
+ // a span that doesn't match `c"foo"` (possible if a proc macro assigns a span
+ // that doesn't actually point to a C string).
+ None
+ };
+ // We can only provide a suggestion if we have a snip and it is not a raw string
+ dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "C string", sugg, cs_note: Some(()) })
}
Ok(LitKind::Char(_)) => {
let sugg =
snippet.map(|snippet| ConcatBytesInvalidSuggestion::CharLit { span, snippet });
- dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "character", sugg })
+ dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "character", sugg, cs_note: None })
}
Ok(LitKind::Str(_, _)) => {
// suggestion would be invalid if we are nested
@@ -38,18 +55,21 @@ fn invalid_type_err(
} else {
None
};
- dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "string", sugg })
+ dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "string", sugg, cs_note: None })
}
Ok(LitKind::Float(_, _)) => {
- dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "float", sugg: None })
+ dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "float", sugg: None, cs_note: None })
}
- Ok(LitKind::Bool(_)) => {
- dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "boolean", sugg: None })
- }
+ Ok(LitKind::Bool(_)) => dcx.emit_err(ConcatBytesInvalid {
+ span,
+ lit_kind: "boolean",
+ sugg: None,
+ cs_note: None,
+ }),
Ok(LitKind::Int(_, _)) if !is_nested => {
let sugg =
snippet.map(|snippet| ConcatBytesInvalidSuggestion::IntLit { span, snippet });
- dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "numeric", sugg })
+ dcx.emit_err(ConcatBytesInvalid { span, lit_kind: "numeric", sugg, cs_note: None })
}
Ok(LitKind::Int(val, LitIntType::Unsuffixed | LitIntType::Unsigned(UintTy::U8))) => {
assert!(val.get() > u8::MAX.into()); // must be an error
diff --git a/compiler/rustc_builtin_macros/src/errors.rs b/compiler/rustc_builtin_macros/src/errors.rs
index 3a2e96a..b7ecfd2 100644
--- a/compiler/rustc_builtin_macros/src/errors.rs
+++ b/compiler/rustc_builtin_macros/src/errors.rs
@@ -215,6 +215,8 @@ pub(crate) struct ConcatBytesInvalid {
pub(crate) lit_kind: &'static str,
#[subdiagnostic]
pub(crate) sugg: Option<ConcatBytesInvalidSuggestion>,
+ #[note(builtin_macros_c_str_note)]
+ pub(crate) cs_note: Option<()>,
}
#[derive(Subdiagnostic)]
@@ -239,6 +241,13 @@ pub(crate) enum ConcatBytesInvalidSuggestion {
span: Span,
snippet: String,
},
+ #[note(builtin_macros_c_str_note)]
+ #[suggestion(builtin_macros_c_str, code = "{as_bstr}", applicability = "machine-applicable")]
+ CStrLit {
+ #[primary_span]
+ span: Span,
+ as_bstr: String,
+ },
#[suggestion(
builtin_macros_number_array,
code = "[{snippet}]",
diff --git a/tests/ui/macros/concat-bytes-error.rs b/tests/ui/macros/concat-bytes-error.rs
index f7f291f..8130fc5 100644
--- a/tests/ui/macros/concat-bytes-error.rs
+++ b/tests/ui/macros/concat-bytes-error.rs
@@ -15,9 +15,10 @@ fn main() {
//~^ SUGGESTION br"tnrsi"
concat_bytes!(r#"tnrsi"#, r###"tnri"###); //~ ERROR cannot concatenate string literals
//~^ SUGGESTION br#"tnrsi"#
- concat_bytes!(c"tnrsi", c"tnri"); //~ ERROR cannot concatenate a C string literal
- concat_bytes!(cr"tnrsi", cr"tnri"); //~ ERROR cannot concatenate a C string literal
- concat_bytes!(cr#"tnrsi"#, cr###"tnri"###); //~ ERROR cannot concatenate a C string literal
+ concat_bytes!(c"tnrsi", c"tnri"); //~ ERROR cannot concatenate C string literals
+ //~^ SUGGESTION b"tnrsi\0"
+ concat_bytes!(cr"tnrsi", cr"tnri"); //~ ERROR cannot concatenate C string literals
+ concat_bytes!(cr#"tnrsi"#, cr###"tnri"###); //~ ERROR cannot concatenate C string literals
// Other literals
concat_bytes!(2.8); //~ ERROR cannot concatenate float literals
diff --git a/tests/ui/macros/concat-bytes-error.stderr b/tests/ui/macros/concat-bytes-error.stderr
index fd498a0..447d7a6 100644
--- a/tests/ui/macros/concat-bytes-error.stderr
+++ b/tests/ui/macros/concat-bytes-error.stderr
@@ -32,98 +32,109 @@
LL | concat_bytes!(r#"tnrsi"#, r###"tnri"###);
| ^^^^^^^^^^ help: try using a byte string: `br#"tnrsi"#`
-error: cannot concatenate a C string literal
+error: cannot concatenate C string literals
+ --> $DIR/concat-bytes-error.rs:18:19
+ |
+LL | concat_bytes!(c"tnrsi", c"tnri");
+ | ^^^^^^^^ help: try using a null-terminated byte string: `b"tnrsi\0"`
+ |
+note: concatenating C strings is ambiguous about including the '\0'
--> $DIR/concat-bytes-error.rs:18:19
|
LL | concat_bytes!(c"tnrsi", c"tnri");
| ^^^^^^^^
+ = note: concatenating C strings is ambiguous about including the '\0'
-error: cannot concatenate a C string literal
- --> $DIR/concat-bytes-error.rs:19:19
+error: cannot concatenate C string literals
+ --> $DIR/concat-bytes-error.rs:20:19
|
LL | concat_bytes!(cr"tnrsi", cr"tnri");
| ^^^^^^^^^
+ |
+ = note: concatenating C strings is ambiguous about including the '\0'
-error: cannot concatenate a C string literal
- --> $DIR/concat-bytes-error.rs:20:19
+error: cannot concatenate C string literals
+ --> $DIR/concat-bytes-error.rs:21:19
|
LL | concat_bytes!(cr#"tnrsi"#, cr###"tnri"###);
| ^^^^^^^^^^^
+ |
+ = note: concatenating C strings is ambiguous about including the '\0'
error: cannot concatenate float literals
- --> $DIR/concat-bytes-error.rs:23:19
+ --> $DIR/concat-bytes-error.rs:24:19
|
LL | concat_bytes!(2.8);
| ^^^
error: cannot concatenate numeric literals
- --> $DIR/concat-bytes-error.rs:24:19
+ --> $DIR/concat-bytes-error.rs:25:19
|
LL | concat_bytes!(300);
| ^^^ help: try wrapping the number in an array: `[300]`
error: cannot concatenate character literals
- --> $DIR/concat-bytes-error.rs:26:19
+ --> $DIR/concat-bytes-error.rs:27:19
|
LL | concat_bytes!('a');
| ^^^ help: try using a byte character: `b'a'`
error: cannot concatenate boolean literals
- --> $DIR/concat-bytes-error.rs:28:19
+ --> $DIR/concat-bytes-error.rs:29:19
|
LL | concat_bytes!(true, false);
| ^^^^
error: cannot concatenate numeric literals
- --> $DIR/concat-bytes-error.rs:29:19
+ --> $DIR/concat-bytes-error.rs:30:19
|
LL | concat_bytes!(42, b"va", b'l');
| ^^ help: try wrapping the number in an array: `[42]`
error: cannot concatenate numeric literals
- --> $DIR/concat-bytes-error.rs:31:19
+ --> $DIR/concat-bytes-error.rs:32:19
|
LL | concat_bytes!(42, b"va", b'l', [1, 2]);
| ^^ help: try wrapping the number in an array: `[42]`
error: cannot concatenate string literals
- --> $DIR/concat-bytes-error.rs:36:9
+ --> $DIR/concat-bytes-error.rs:37:9
|
LL | "hi",
| ^^^^
error: cannot concatenate character literals
- --> $DIR/concat-bytes-error.rs:39:9
+ --> $DIR/concat-bytes-error.rs:40:9
|
LL | 'a',
| ^^^ help: try using a byte character: `b'a'`
error: cannot concatenate boolean literals
- --> $DIR/concat-bytes-error.rs:43:9
+ --> $DIR/concat-bytes-error.rs:44:9
|
LL | true,
| ^^^^
error: cannot concatenate boolean literals
- --> $DIR/concat-bytes-error.rs:46:9
+ --> $DIR/concat-bytes-error.rs:47:9
|
LL | false,
| ^^^^^
error: cannot concatenate float literals
- --> $DIR/concat-bytes-error.rs:49:9
+ --> $DIR/concat-bytes-error.rs:50:9
|
LL | 2.6,
| ^^^
error: numeric literal is out of bounds
- --> $DIR/concat-bytes-error.rs:52:9
+ --> $DIR/concat-bytes-error.rs:53:9
|
LL | 265,
| ^^^
error: expected a byte literal
- --> $DIR/concat-bytes-error.rs:55:9
+ --> $DIR/concat-bytes-error.rs:56:9
|
LL | -33,
| ^^^
@@ -131,7 +142,7 @@
= note: only byte literals (like `b"foo"`, `b's'` and `[3, 4, 5]`) can be passed to `concat_bytes!()`
error: cannot concatenate doubly nested array
- --> $DIR/concat-bytes-error.rs:58:9
+ --> $DIR/concat-bytes-error.rs:59:9
|
LL | b"hi!",
| ^^^^^^
@@ -140,43 +151,43 @@
= help: try flattening the array
error: cannot concatenate doubly nested array
- --> $DIR/concat-bytes-error.rs:61:9
+ --> $DIR/concat-bytes-error.rs:62:9
|
LL | [5, 6, 7],
| ^^^^^^^^^
error: cannot concatenate numeric literals
- --> $DIR/concat-bytes-error.rs:63:19
+ --> $DIR/concat-bytes-error.rs:64:19
|
LL | concat_bytes!(5u16);
| ^^^^ help: try wrapping the number in an array: `[5u16]`
error: numeric literal is not a `u8`
- --> $DIR/concat-bytes-error.rs:65:20
+ --> $DIR/concat-bytes-error.rs:66:20
|
LL | concat_bytes!([5u16]);
| ^^^^
error: repeat count is not a positive number
- --> $DIR/concat-bytes-error.rs:66:23
+ --> $DIR/concat-bytes-error.rs:67:23
|
LL | concat_bytes!([3; ()]);
| ^^
error: repeat count is not a positive number
- --> $DIR/concat-bytes-error.rs:67:23
+ --> $DIR/concat-bytes-error.rs:68:23
|
LL | concat_bytes!([3; -2]);
| ^^
error: repeat count is not a positive number
- --> $DIR/concat-bytes-error.rs:68:25
+ --> $DIR/concat-bytes-error.rs:69:25
|
LL | concat_bytes!([pie; -2]);
| ^^
error: expected a byte literal
- --> $DIR/concat-bytes-error.rs:69:20
+ --> $DIR/concat-bytes-error.rs:70:20
|
LL | concat_bytes!([pie; 2]);
| ^^^
@@ -184,25 +195,25 @@
= note: only byte literals (like `b"foo"`, `b's'` and `[3, 4, 5]`) can be passed to `concat_bytes!()`
error: cannot concatenate float literals
- --> $DIR/concat-bytes-error.rs:70:20
+ --> $DIR/concat-bytes-error.rs:71:20
|
LL | concat_bytes!([2.2; 0]);
| ^^^
error: repeat count is not a positive number
- --> $DIR/concat-bytes-error.rs:71:25
+ --> $DIR/concat-bytes-error.rs:72:25
|
LL | concat_bytes!([5.5; ()]);
| ^^
error: cannot concatenate doubly nested array
- --> $DIR/concat-bytes-error.rs:72:20
+ --> $DIR/concat-bytes-error.rs:73:20
|
LL | concat_bytes!([[1, 2, 3]; 3]);
| ^^^^^^^^^
error: cannot concatenate doubly nested array
- --> $DIR/concat-bytes-error.rs:73:20
+ --> $DIR/concat-bytes-error.rs:74:20
|
LL | concat_bytes!([[42; 2]; 3]);
| ^^^^^^^
