diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs index 05216be06ff56..5c44bfb0cf3f3 100644 --- a/compiler/rustc_parse/src/parser/expr.rs +++ b/compiler/rustc_parse/src/parser/expr.rs @@ -1524,7 +1524,7 @@ impl<'a> Parser<'a> { }, ) } else if this.check_inline_const(0) { - this.parse_const_block(lo) + this.parse_const_block(lo, false) } else if this.may_recover() && this.is_do_catch_block() { this.recover_do_catch() } else if this.is_try_block() { diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs index a6b956b09bc16..f95fe61b0abdc 100644 --- a/compiler/rustc_parse/src/parser/mod.rs +++ b/compiler/rustc_parse/src/parser/mod.rs @@ -1270,7 +1270,7 @@ impl<'a> Parser<'a> { } /// Parses inline const expressions. - fn parse_const_block(&mut self, span: Span) -> PResult<'a, Box> { + fn parse_const_block(&mut self, span: Span, pat: bool) -> PResult<'a, Box> { self.expect_keyword(exp!(Const))?; let (attrs, blk) = self.parse_inner_attrs_and_block(None)?; let anon_const = AnonConst { @@ -1279,7 +1279,18 @@ impl<'a> Parser<'a> { mgca_disambiguation: MgcaDisambiguation::AnonConst, }; let blk_span = anon_const.value.span; - let kind = ExprKind::ConstBlock(anon_const); + let kind = if pat { + let guar = self + .dcx() + .struct_span_err(blk_span, "const blocks cannot be used as patterns") + .with_help( + "use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead", + ) + .emit(); + ExprKind::Err(guar) + } else { + ExprKind::ConstBlock(anon_const) + }; Ok(self.mk_expr_with_attrs(span.to(blk_span), kind, attrs)) } diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs index c1e864985e190..bc73c3a2007a0 100644 --- a/compiler/rustc_parse/src/parser/pat.rs +++ b/compiler/rustc_parse/src/parser/pat.rs @@ -785,10 +785,8 @@ impl<'a> Parser<'a> { } else if self.eat_keyword(exp!(Box)) { self.parse_pat_box()? } else if self.check_inline_const(0) { - // Parse `const pat`. - // NOTE: This will always error later during AST lowering because - // inline const cannot be used as patterns. - let const_expr = self.parse_const_block(lo.to(self.token.span))?; + // Parse `const pat` + let const_expr = self.parse_const_block(lo.to(self.token.span), true)?; if let Some(re) = self.parse_range_end() { self.parse_pat_range_begin_with(const_expr, re)? @@ -1283,7 +1281,7 @@ impl<'a> Parser<'a> { .then_some(self.prev_token.span); let bound = if self.check_inline_const(0) { - self.parse_const_block(self.token.span) + self.parse_const_block(self.token.span, true) } else if self.check_path() { let lo = self.token.span; let (qself, path) = if self.eat_lt() { diff --git a/tests/ui/inline-const/in-pat-recovery.rs b/tests/ui/inline-const/in-pat-recovery.rs index d519217fad3b5..037c58d3bf98c 100644 --- a/tests/ui/inline-const/in-pat-recovery.rs +++ b/tests/ui/inline-const/in-pat-recovery.rs @@ -4,63 +4,63 @@ fn main() { match 1 { const { 1 + 7 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns 2 => {} _ => {} } match 5 { const { 1 } ..= 10 => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { 1 ..= const { 10 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { const { 1 } ..= const { 10 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns - //~| ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns + //~| ERROR const blocks cannot be used as patterns _ => {} } match 5 { const { 1 } .. 10 => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { 1 .. const { 10 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { const { 1 + 2 } ..= 10 => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { 1 ..= const { 5 + 5 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { const { 3 } .. => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } match 5 { ..= const { 7 } => {} - //~^ ERROR arbitrary expressions aren't allowed in patterns + //~^ ERROR const blocks cannot be used as patterns _ => {} } } diff --git a/tests/ui/inline-const/in-pat-recovery.stderr b/tests/ui/inline-const/in-pat-recovery.stderr index 376c43aaecca6..55adb5c49a6d1 100644 --- a/tests/ui/inline-const/in-pat-recovery.stderr +++ b/tests/ui/inline-const/in-pat-recovery.stderr @@ -1,88 +1,88 @@ -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:6:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:6:15 | LL | const { 1 + 7 } => {} - | ^^^^^^^^^^^^^^^ + | ^^^^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:13:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:13:15 | LL | const { 1 } ..= 10 => {} - | ^^^^^^^^^^^ + | ^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:19:15 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:19:21 | LL | 1 ..= const { 10 } => {} - | ^^^^^^^^^^^^ + | ^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:25:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:25:15 | LL | const { 1 } ..= const { 10 } => {} - | ^^^^^^^^^^^ + | ^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:25:25 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:25:31 | LL | const { 1 } ..= const { 10 } => {} - | ^^^^^^^^^^^^ + | ^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:32:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:32:15 | LL | const { 1 } .. 10 => {} - | ^^^^^^^^^^^ + | ^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:38:14 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:38:20 | LL | 1 .. const { 10 } => {} - | ^^^^^^^^^^^^ + | ^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:44:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:44:15 | LL | const { 1 + 2 } ..= 10 => {} - | ^^^^^^^^^^^^^^^ + | ^^^^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:50:15 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:50:21 | LL | 1 ..= const { 5 + 5 } => {} - | ^^^^^^^^^^^^^^^ + | ^^^^^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:56:9 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:56:15 | LL | const { 3 } .. => {} - | ^^^^^^^^^^^ + | ^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead -error: arbitrary expressions aren't allowed in patterns - --> $DIR/in-pat-recovery.rs:62:13 +error: const blocks cannot be used as patterns + --> $DIR/in-pat-recovery.rs:62:19 | LL | ..= const { 7 } => {} - | ^^^^^^^^^^^ + | ^^^^^ | = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead diff --git a/tests/ui/inline-const/reject-const-block-pat-pre-expansion.rs b/tests/ui/inline-const/reject-const-block-pat-pre-expansion.rs new file mode 100644 index 0000000000000..9af4925c0432a --- /dev/null +++ b/tests/ui/inline-const/reject-const-block-pat-pre-expansion.rs @@ -0,0 +1,12 @@ +//! Regression test for : reject inline const +//! patterns pre-expansion when possible. + +macro_rules! analyze { ($p:pat) => {}; } +analyze!(const { 0 }); +//~^ ERROR: const blocks cannot be used as patterns + +#[cfg(false)] +fn scope() { let const { 0 }; } +//~^ ERROR: const blocks cannot be used as patterns + +fn main() {} diff --git a/tests/ui/inline-const/reject-const-block-pat-pre-expansion.stderr b/tests/ui/inline-const/reject-const-block-pat-pre-expansion.stderr new file mode 100644 index 0000000000000..034b97699396e --- /dev/null +++ b/tests/ui/inline-const/reject-const-block-pat-pre-expansion.stderr @@ -0,0 +1,18 @@ +error: const blocks cannot be used as patterns + --> $DIR/reject-const-block-pat-pre-expansion.rs:9:24 + | +LL | fn scope() { let const { 0 }; } + | ^^^^^ + | + = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead + +error: const blocks cannot be used as patterns + --> $DIR/reject-const-block-pat-pre-expansion.rs:5:16 + | +LL | analyze!(const { 0 }); + | ^^^^^ + | + = help: use a named `const`-item or an `if`-guard (`x if x == const { ... }`) instead + +error: aborting due to 2 previous errors +