diff --git a/compiler/rustc_ast_lowering/messages.ftl b/compiler/rustc_ast_lowering/messages.ftl index 73001c9990c..aa5a85b9c4c 100644 --- a/compiler/rustc_ast_lowering/messages.ftl +++ b/compiler/rustc_ast_lowering/messages.ftl @@ -5,6 +5,7 @@ ast_lowering_abi_specified_multiple_times = ast_lowering_arbitrary_expression_in_pattern = arbitrary expressions aren't allowed in patterns + .pattern_from_macro_note = the :expr fragment specifier forces the metavariable's content to be an expression ast_lowering_argument = argument diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs index 6f70e135c72..02744d16b42 100644 --- a/compiler/rustc_ast_lowering/src/errors.rs +++ b/compiler/rustc_ast_lowering/src/errors.rs @@ -368,6 +368,8 @@ pub struct NeverPatternWithGuard { pub struct ArbitraryExpressionInPattern { #[primary_span] pub span: Span, + #[note(ast_lowering_pattern_from_macro_note)] + pub pattern_from_macro_note: bool, } #[derive(Diagnostic)] diff --git a/compiler/rustc_ast_lowering/src/pat.rs b/compiler/rustc_ast_lowering/src/pat.rs index 118a7322fbd..32de07a0755 100644 --- a/compiler/rustc_ast_lowering/src/pat.rs +++ b/compiler/rustc_ast_lowering/src/pat.rs @@ -339,7 +339,11 @@ fn lower_expr_within_pat(&mut self, expr: &Expr, allow_paths: bool) -> &'hir hir ExprKind::Path(..) if allow_paths => {} ExprKind::Unary(UnOp::Neg, inner) if matches!(inner.kind, ExprKind::Lit(_)) => {} _ => { - let guar = self.dcx().emit_err(ArbitraryExpressionInPattern { span: expr.span }); + let pattern_from_macro = expr.is_approximately_pattern(); + let guar = self.dcx().emit_err(ArbitraryExpressionInPattern { + span: expr.span, + pattern_from_macro_note: pattern_from_macro, + }); return self.arena.alloc(self.expr_err(expr.span, guar)); } } diff --git a/tests/ui/issues/issue-43250.stderr b/tests/ui/issues/issue-43250.stderr index f729c5cf10c..01c22a9e791 100644 --- a/tests/ui/issues/issue-43250.stderr +++ b/tests/ui/issues/issue-43250.stderr @@ -3,12 +3,16 @@ error: arbitrary expressions aren't allowed in patterns | LL | m!(y); | ^ + | + = note: the :expr fragment specifier forces the metavariable's content to be an expression error: arbitrary expressions aren't allowed in patterns --> $DIR/issue-43250.rs:11:8 | LL | m!(C); | ^ + | + = note: the :expr fragment specifier forces the metavariable's content to be an expression error: aborting due to 2 previous errors diff --git a/tests/ui/lowering/expr-in-pat-issue-99380.rs b/tests/ui/lowering/expr-in-pat-issue-99380.rs new file mode 100644 index 00000000000..1d4a047f717 --- /dev/null +++ b/tests/ui/lowering/expr-in-pat-issue-99380.rs @@ -0,0 +1,11 @@ +macro_rules! foo { + ($p:expr) => { + if let $p = Some(42) { + return; + } + }; +} + +fn main() { + foo!(Some(3)); //~ ERROR arbitrary expressions aren't allowed in patterns +} diff --git a/tests/ui/lowering/expr-in-pat-issue-99380.stderr b/tests/ui/lowering/expr-in-pat-issue-99380.stderr new file mode 100644 index 00000000000..7438bba270c --- /dev/null +++ b/tests/ui/lowering/expr-in-pat-issue-99380.stderr @@ -0,0 +1,10 @@ +error: arbitrary expressions aren't allowed in patterns + --> $DIR/expr-in-pat-issue-99380.rs:10:10 + | +LL | foo!(Some(3)); + | ^^^^^^^ + | + = note: the :expr fragment specifier forces the metavariable's content to be an expression + +error: aborting due to 1 previous error + diff --git a/tests/ui/macros/vec-macro-in-pattern.stderr b/tests/ui/macros/vec-macro-in-pattern.stderr index 447f5dcf864..7c87f3b7b8e 100644 --- a/tests/ui/macros/vec-macro-in-pattern.stderr +++ b/tests/ui/macros/vec-macro-in-pattern.stderr @@ -4,6 +4,7 @@ error: arbitrary expressions aren't allowed in patterns LL | Some(vec![43]) => {} | ^^^^^^^^ | + = note: the :expr fragment specifier forces the metavariable's content to be an expression = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 1 previous error diff --git a/tests/ui/match/expr_before_ident_pat.stderr b/tests/ui/match/expr_before_ident_pat.stderr index 57a2d2b26cf..2f59573b53f 100644 --- a/tests/ui/match/expr_before_ident_pat.stderr +++ b/tests/ui/match/expr_before_ident_pat.stderr @@ -9,6 +9,8 @@ error: arbitrary expressions aren't allowed in patterns | LL | funny!(a, a); | ^ + | + = note: the :expr fragment specifier forces the metavariable's content to be an expression error: aborting due to 2 previous errors diff --git a/tests/ui/pattern/issue-92074-macro-ice.stderr b/tests/ui/pattern/issue-92074-macro-ice.stderr index b340afff010..bf53eb4bbcd 100644 --- a/tests/ui/pattern/issue-92074-macro-ice.stderr +++ b/tests/ui/pattern/issue-92074-macro-ice.stderr @@ -7,6 +7,7 @@ LL | () => { force_expr!(Vec::new()) } LL | assert!(matches!(x, En::A(make_vec!()))); | ----------- in this macro invocation | + = note: the :expr fragment specifier forces the metavariable's content to be an expression = note: this error originates in the macro `make_vec` (in Nightly builds, run with -Z macro-backtrace for more info) error: arbitrary expressions aren't allowed in patterns @@ -18,6 +19,7 @@ LL | () => { force_pat!(get_usize(), get_usize()) } LL | assert!(matches!(5, make_pat!())); | ----------- in this macro invocation | + = note: the :expr fragment specifier forces the metavariable's content to be an expression = note: this error originates in the macro `make_pat` (in Nightly builds, run with -Z macro-backtrace for more info) error: arbitrary expressions aren't allowed in patterns @@ -29,6 +31,7 @@ LL | () => { force_pat!(get_usize(), get_usize()) } LL | assert!(matches!(5, make_pat!())); | ----------- in this macro invocation | + = note: the :expr fragment specifier forces the metavariable's content to be an expression = note: this error originates in the macro `make_pat` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 3 previous errors