diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs index efbd1711daa92..9c3db7abc1ccc 100644 --- a/compiler/rustc_ast_lowering/src/expr.rs +++ b/compiler/rustc_ast_lowering/src/expr.rs @@ -671,10 +671,13 @@ impl<'hir> LoweringContext<'_, 'hir> { let span = self.lower_span(arm.span); self.lower_attrs(hir_id, &arm.attrs, arm.span); let is_never_pattern = pat.is_never_pattern(); - let body = if let Some(body) = &arm.body + // We need to lower the body even if it's unneeded for never pattern in match, + // ensure that we can get HirId for DefId if need (issue #137708). + let body = arm.body.as_ref().map(|x| self.lower_expr(x)); + let body = if let Some(body) = body && !is_never_pattern { - self.lower_expr(body) + body } else { // Either `body.is_none()` or `is_never_pattern` here. if !is_never_pattern { diff --git a/tests/ui/never_type/unused_trait_in_never_pattern_body.rs b/tests/ui/never_type/unused_trait_in_never_pattern_body.rs new file mode 100644 index 0000000000000..8179c94b72b23 --- /dev/null +++ b/tests/ui/never_type/unused_trait_in_never_pattern_body.rs @@ -0,0 +1,12 @@ +fn a() { + match 0 { + ! => || { //~ ERROR `!` patterns are experimental + //~^ ERROR a never pattern is always unreachable + //~^^ ERROR mismatched types + use std::ops::Add; + 0.add(1) + }, + } +} + +fn main() {} diff --git a/tests/ui/never_type/unused_trait_in_never_pattern_body.stderr b/tests/ui/never_type/unused_trait_in_never_pattern_body.stderr new file mode 100644 index 0000000000000..18ca9f12b7e81 --- /dev/null +++ b/tests/ui/never_type/unused_trait_in_never_pattern_body.stderr @@ -0,0 +1,36 @@ +error[E0658]: `!` patterns are experimental + --> $DIR/unused_trait_in_never_pattern_body.rs:3:9 + | +LL | ! => || { + | ^ + | + = note: see issue #118155 for more information + = help: add `#![feature(never_patterns)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date + +error: a never pattern is always unreachable + --> $DIR/unused_trait_in_never_pattern_body.rs:3:14 + | +LL | ! => || { + | ______________^ +LL | | +LL | | +LL | | use std::ops::Add; +LL | | 0.add(1) +LL | | }, + | | ^ + | | | + | |_________this will never be executed + | help: remove this expression + +error: mismatched types + --> $DIR/unused_trait_in_never_pattern_body.rs:3:9 + | +LL | ! => || { + | ^ a never pattern must be used on an uninhabited type + | + = note: the matched value is of type `i32` + +error: aborting due to 3 previous errors + +For more information about this error, try `rustc --explain E0658`.