diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs index 53e2b4e6accb4..b732e4493742b 100644 --- a/compiler/rustc_expand/src/expand.rs +++ b/compiler/rustc_expand/src/expand.rs @@ -735,7 +735,14 @@ impl<'a, 'b> MacroExpander<'a, 'b> { }); } }; - fragment_kind.expect_from_annotatables(items) + if fragment_kind == AstFragmentKind::Expr && items.is_empty() { + let msg = + "removing an expression is not supported in this position"; + self.cx.span_err(span, msg); + fragment_kind.dummy(span) + } else { + fragment_kind.expect_from_annotatables(items) + } } Err(mut err) => { err.emit(); diff --git a/src/test/ui/macros/attr-empty-expr.rs b/src/test/ui/macros/attr-empty-expr.rs new file mode 100644 index 0000000000000..d4d1a3ee71e67 --- /dev/null +++ b/src/test/ui/macros/attr-empty-expr.rs @@ -0,0 +1,11 @@ +// AST-based macro attributes expanding to an empty expression produce an error and not ICE. + +#![feature(custom_test_frameworks)] +#![feature(stmt_expr_attributes)] +#![feature(test)] + +fn main() { + let _ = #[test] 0; //~ ERROR removing an expression is not supported in this position + let _ = #[bench] 1; //~ ERROR removing an expression is not supported in this position + let _ = #[test_case] 2; //~ ERROR removing an expression is not supported in this position +} diff --git a/src/test/ui/macros/attr-empty-expr.stderr b/src/test/ui/macros/attr-empty-expr.stderr new file mode 100644 index 0000000000000..53721053bcc08 --- /dev/null +++ b/src/test/ui/macros/attr-empty-expr.stderr @@ -0,0 +1,20 @@ +error: removing an expression is not supported in this position + --> $DIR/attr-empty-expr.rs:8:13 + | +LL | let _ = #[test] 0; + | ^^^^^^^ + +error: removing an expression is not supported in this position + --> $DIR/attr-empty-expr.rs:9:13 + | +LL | let _ = #[bench] 1; + | ^^^^^^^^ + +error: removing an expression is not supported in this position + --> $DIR/attr-empty-expr.rs:10:13 + | +LL | let _ = #[test_case] 2; + | ^^^^^^^^^^^^ + +error: aborting due to 3 previous errors +