Move PatKind::Lit checking from ast_validation to ast lowering
Fixes #92074 This allows us to insert an `ExprKind::Err` when an invalid expression is used in a literal pattern, preventing later stages of compilation from seeing an unexpected literal pattern.
This commit is contained in:
Aaron Hill
parent
4f49627c6f
commit
137c374c41
5 changed files with 111 additions and 56 deletions
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@ -24,7 +24,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
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break self.lower_pat_ident(pattern, binding_mode, ident, lower_sub);
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}
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PatKind::Lit(ref e) => break hir::PatKind::Lit(self.lower_expr(e)),
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PatKind::Lit(ref e) => {
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break hir::PatKind::Lit(self.lower_expr_within_pat(e, false));
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}
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PatKind::TupleStruct(ref qself, ref path, ref pats) => {
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let qpath = self.lower_qpath(
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pattern.id,
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@ -81,8 +83,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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}
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PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => {
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break hir::PatKind::Range(
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e1.as_deref().map(|e| self.lower_expr(e)),
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e2.as_deref().map(|e| self.lower_expr(e)),
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e1.as_deref().map(|e| self.lower_expr_within_pat(e, true)),
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e2.as_deref().map(|e| self.lower_expr_within_pat(e, true)),
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self.lower_range_end(end, e2.is_some()),
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);
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}
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@ -314,4 +316,33 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
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RangeEnd::Excluded | RangeEnd::Included(_) => hir::RangeEnd::Included,
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}
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}
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/// Matches `'-' lit | lit (cf. parser::Parser::parse_literal_maybe_minus)`,
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/// or paths for ranges.
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//
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// FIXME: do we want to allow `expr -> pattern` conversion to create path expressions?
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// That means making this work:
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//
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// ```rust,ignore (FIXME)
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// struct S;
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// macro_rules! m {
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// ($a:expr) => {
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// let $a = S;
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// }
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// }
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// m!(S);
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// ```
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fn lower_expr_within_pat(&mut self, expr: &Expr, allow_paths: bool) -> &'hir hir::Expr<'hir> {
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match expr.kind {
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ExprKind::Lit(..) | ExprKind::ConstBlock(..) | ExprKind::Err => {}
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ExprKind::Path(..) if allow_paths => {}
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ExprKind::Unary(UnOp::Neg, ref inner) if matches!(inner.kind, ExprKind::Lit(_)) => {}
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_ => {
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self.diagnostic()
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.span_err(expr.span, "arbitrary expressions aren't allowed in patterns");
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return self.arena.alloc(self.expr_err(expr.span));
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}
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}
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self.lower_expr(expr)
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}
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}
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@ -302,34 +302,6 @@ impl<'a> AstValidator<'a> {
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}
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}
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/// Matches `'-' lit | lit (cf. parser::Parser::parse_literal_maybe_minus)`,
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/// or paths for ranges.
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//
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// FIXME: do we want to allow `expr -> pattern` conversion to create path expressions?
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// That means making this work:
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//
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// ```rust,ignore (FIXME)
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// struct S;
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// macro_rules! m {
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// ($a:expr) => {
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// let $a = S;
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// }
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// }
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// m!(S);
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// ```
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fn check_expr_within_pat(&self, expr: &Expr, allow_paths: bool) {
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match expr.kind {
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ExprKind::Lit(..) | ExprKind::ConstBlock(..) | ExprKind::Err => {}
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ExprKind::Path(..) if allow_paths => {}
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ExprKind::Unary(UnOp::Neg, ref inner) if matches!(inner.kind, ExprKind::Lit(_)) => {}
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_ => self.err_handler().span_err(
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expr.span,
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"arbitrary expressions aren't allowed \
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in patterns",
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),
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}
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}
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fn check_late_bound_lifetime_defs(&self, params: &[GenericParam]) {
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// Check only lifetime parameters are present and that the lifetime
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// parameters that are present have no bounds.
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@ -1426,25 +1398,6 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
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visit::walk_param_bound(self, bound)
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}
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fn visit_pat(&mut self, pat: &'a Pat) {
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match &pat.kind {
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PatKind::Lit(expr) => {
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self.check_expr_within_pat(expr, false);
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}
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PatKind::Range(start, end, _) => {
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if let Some(expr) = start {
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self.check_expr_within_pat(expr, true);
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}
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if let Some(expr) = end {
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self.check_expr_within_pat(expr, true);
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}
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}
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_ => {}
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}
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visit::walk_pat(self, pat)
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}
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fn visit_poly_trait_ref(&mut self, t: &'a PolyTraitRef, m: &'a TraitBoundModifier) {
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self.check_late_bound_lifetime_defs(&t.bound_generic_params);
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visit::walk_poly_trait_ref(self, t, m);
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@ -1,15 +1,15 @@
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error: arbitrary expressions aren't allowed in patterns
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--> $DIR/expr_before_ident_pat.rs:12:12
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LL | funny!(a, a);
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| ^
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error[E0425]: cannot find value `a` in this scope
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--> $DIR/expr_before_ident_pat.rs:12:12
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LL | funny!(a, a);
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| ^ not found in this scope
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error: arbitrary expressions aren't allowed in patterns
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--> $DIR/expr_before_ident_pat.rs:12:12
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LL | funny!(a, a);
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| ^
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0425`.
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36
src/test/ui/pattern/issue-92074-macro-ice.rs
Normal file
36
src/test/ui/pattern/issue-92074-macro-ice.rs
Normal file
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@ -0,0 +1,36 @@
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pub enum En {
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A(Vec<u8>)
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}
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fn get_usize() -> usize {
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0
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}
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macro_rules! force_expr {
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($e:expr) => { $e }
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}
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macro_rules! force_pat {
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($a:expr, $b:expr) => { $a..=$b }
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}
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macro_rules! make_vec {
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() => { force_expr!(Vec::new()) } //~ ERROR arbitrary expressions aren't allowed
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}
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macro_rules! make_pat {
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() => { force_pat!(get_usize(), get_usize()) }
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//~^ ERROR arbitrary expressions aren't allowed
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//~| ERROR arbitrary expressions aren't allowed
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}
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#[allow(unreachable_code)]
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fn f() -> Result<(), impl core::fmt::Debug> {
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let x: En = loop {};
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assert!(matches!(x, En::A(make_vec!())));
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assert!(matches!(5, make_pat!()));
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Ok::<(), &'static str>(())
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}
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fn main() {}
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35
src/test/ui/pattern/issue-92074-macro-ice.stderr
Normal file
35
src/test/ui/pattern/issue-92074-macro-ice.stderr
Normal file
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@ -0,0 +1,35 @@
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error: arbitrary expressions aren't allowed in patterns
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--> $DIR/issue-92074-macro-ice.rs:18:25
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LL | () => { force_expr!(Vec::new()) }
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| ^^^^^^^^^^
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...
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LL | assert!(matches!(x, En::A(make_vec!())));
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| ----------- in this macro invocation
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= note: this error originates in the macro `make_vec` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: arbitrary expressions aren't allowed in patterns
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--> $DIR/issue-92074-macro-ice.rs:22:24
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LL | () => { force_pat!(get_usize(), get_usize()) }
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| ^^^^^^^^^^^
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...
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LL | assert!(matches!(5, make_pat!()));
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| ----------- in this macro invocation
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= note: this error originates in the macro `make_pat` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: arbitrary expressions aren't allowed in patterns
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--> $DIR/issue-92074-macro-ice.rs:22:37
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LL | () => { force_pat!(get_usize(), get_usize()) }
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| ^^^^^^^^^^^
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...
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LL | assert!(matches!(5, make_pat!()));
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| ----------- in this macro invocation
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= note: this error originates in the macro `make_pat` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: aborting due to 3 previous errors
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