diff options
| -rw-r--r-- | src/librustc_ast_lowering/pat.rs | 33 | ||||
| -rw-r--r-- | src/test/ui/issues/issue-72574-1.rs | 8 | ||||
| -rw-r--r-- | src/test/ui/issues/issue-72574-1.stderr | 14 | ||||
| -rw-r--r-- | src/test/ui/issues/issue-72574-2.rs | 10 | ||||
| -rw-r--r-- | src/test/ui/issues/issue-72574-2.stderr | 14 |
5 files changed, 76 insertions, 3 deletions
diff --git a/src/librustc_ast_lowering/pat.rs b/src/librustc_ast_lowering/pat.rs index 496e401d061..55c1f802663 100644 --- a/src/librustc_ast_lowering/pat.rs +++ b/src/librustc_ast_lowering/pat.rs @@ -3,6 +3,7 @@ use super::{ImplTraitContext, LoweringContext, ParamMode}; use rustc_ast::ast::*; use rustc_ast::ptr::P; use rustc_data_structures::stack::ensure_sufficient_stack; +use rustc_errors::Applicability; use rustc_hir as hir; use rustc_hir::def::Res; use rustc_span::symbol::Ident; @@ -102,10 +103,36 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // Note that unlike for slice patterns, // where `xs @ ..` is a legal sub-slice pattern, // it is not a legal sub-tuple pattern. - if pat.is_rest() { - rest = Some((idx, pat.span)); - break; + match pat.kind { + // Found a sub-tuple rest pattern + PatKind::Rest => { + rest = Some((idx, pat.span)); + break; + } + // Found a sub-tuple pattern `$binding_mode $ident @ ..`. + // This is not allowed as a sub-tuple pattern + PatKind::Ident(ref _bm, ident, Some(ref sub)) if sub.is_rest() => { + rest = Some((idx, pat.span)); + let sp = pat.span; + self.diagnostic() + .struct_span_err( + sp, + &format!("`{} @` is not allowed in a {}", ident.name, ctx), + ) + .span_label(sp, "this is only allowed in slice patterns") + .help("remove this and bind each tuple field independently") + .span_suggestion_verbose( + sp, + &format!("if you don't need to use the contents of {}, discard the tuple's remaining fields", ident), + "..".to_string(), + Applicability::MaybeIncorrect, + ) + .emit(); + break; + } + _ => {} } + // It was not a sub-tuple pattern so lower it normally. elems.push(self.lower_pat(pat)); } diff --git a/src/test/ui/issues/issue-72574-1.rs b/src/test/ui/issues/issue-72574-1.rs new file mode 100644 index 00000000000..efbb0bfb150 --- /dev/null +++ b/src/test/ui/issues/issue-72574-1.rs @@ -0,0 +1,8 @@ +fn main() { + let x = (1, 2, 3); + match x { + (_a, _x @ ..) => {} + _ => {} + } +} +//~^^^^ ERROR `_x @` is not allowed in a tuple diff --git a/src/test/ui/issues/issue-72574-1.stderr b/src/test/ui/issues/issue-72574-1.stderr new file mode 100644 index 00000000000..329f7d008d4 --- /dev/null +++ b/src/test/ui/issues/issue-72574-1.stderr @@ -0,0 +1,14 @@ +error: `_x @` is not allowed in a tuple + --> $DIR/issue-72574-1.rs:4:14 + | +LL | (_a, _x @ ..) => {} + | ^^^^^^^ this is only allowed in slice patterns + | + = help: remove this and bind each tuple field independently +help: if you don't need to use the contents of _x, discard the tuple's remaining fields + | +LL | (_a, ..) => {} + | ^^ + +error: aborting due to previous error + diff --git a/src/test/ui/issues/issue-72574-2.rs b/src/test/ui/issues/issue-72574-2.rs new file mode 100644 index 00000000000..0c8f6fcc508 --- /dev/null +++ b/src/test/ui/issues/issue-72574-2.rs @@ -0,0 +1,10 @@ +struct Binder(i32, i32, i32); + +fn main() { + let x = Binder(1, 2, 3); + match x { + Binder(_a, _x @ ..) => {} + _ => {} + } +} +//~^^^^ ERROR `_x @` is not allowed in a tuple struct diff --git a/src/test/ui/issues/issue-72574-2.stderr b/src/test/ui/issues/issue-72574-2.stderr new file mode 100644 index 00000000000..6faa57bcca6 --- /dev/null +++ b/src/test/ui/issues/issue-72574-2.stderr @@ -0,0 +1,14 @@ +error: `_x @` is not allowed in a tuple struct + --> $DIR/issue-72574-2.rs:6:20 + | +LL | Binder(_a, _x @ ..) => {} + | ^^^^^^^ this is only allowed in slice patterns + | + = help: remove this and bind each tuple field independently +help: if you don't need to use the contents of _x, discard the tuple's remaining fields + | +LL | Binder(_a, ..) => {} + | ^^ + +error: aborting due to previous error + |