diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs index 964c81dd466..36f059531d3 100644 --- a/src/libsyntax/ext/expand.rs +++ b/src/libsyntax/ext/expand.rs @@ -686,12 +686,13 @@ impl<'a, 'b> MacroExpander<'a, 'b> { ); } - fn parse_ast_fragment(&mut self, - toks: TokenStream, - kind: AstFragmentKind, - path: &Path, - span: Span) - -> AstFragment { + fn parse_ast_fragment( + &mut self, + toks: TokenStream, + kind: AstFragmentKind, + path: &Path, + span: Span, + ) -> AstFragment { let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::>()); match parser.parse_ast_fragment(kind, false) { Ok(fragment) => { @@ -700,6 +701,21 @@ impl<'a, 'b> MacroExpander<'a, 'b> { } Err(mut err) => { err.set_span(span); + match kind { + AstFragmentKind::Ty => { + err.span_label( + span, + "this macro call doesn't expand to a type", + ); + } + AstFragmentKind::Pat => { + err.span_label( + span, + "this macro call doesn't expand to a pattern", + ); + } + _ => {} + }; err.emit(); self.cx.trace_macros_diag(); kind.dummy(span) diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs index 7401f256412..a9d0b739d6a 100644 --- a/src/libsyntax/ext/tt/macro_rules.rs +++ b/src/libsyntax/ext/tt/macro_rules.rs @@ -70,6 +70,29 @@ impl<'a> ParserAnyMacro<'a> { } else if !parser.sess.source_map().span_to_filename(parser.token.span).is_real() { e.span_label(site_span, "in this macro invocation"); } + match kind { + AstFragmentKind::Ty => { + e.span_label( + site_span, + "this macro call doesn't expand to a type", + ); + } + AstFragmentKind::Pat if macro_ident.name == sym::vec => { + e.span_label( + site_span, + "use a slice pattern here instead", + ); + e.help("for more information, see https://doc.rust-lang.org/edition-guide/\ + rust-2018/slice-patterns.html"); + } + AstFragmentKind::Pat => { + e.span_label( + site_span, + "this macro call doesn't expand to a pattern", + ); + } + _ => {} + }; e })); diff --git a/src/test/ui/proc-macro/lifetimes.stderr b/src/test/ui/proc-macro/lifetimes.stderr index 2356a119530..6e91201405c 100644 --- a/src/test/ui/proc-macro/lifetimes.stderr +++ b/src/test/ui/proc-macro/lifetimes.stderr @@ -2,7 +2,7 @@ error: expected type, found `'` --> $DIR/lifetimes.rs:9:10 | LL | type A = single_quote_alone!(); - | ^^^^^^^^^^^^^^^^^^^^^ + | ^^^^^^^^^^^^^^^^^^^^^ this macro call doesn't expand to a type error: aborting due to previous error diff --git a/src/test/ui/suggestions/vec-macro-in-pattern.rs b/src/test/ui/suggestions/vec-macro-in-pattern.rs new file mode 100644 index 00000000000..5c42a6bdbd4 --- /dev/null +++ b/src/test/ui/suggestions/vec-macro-in-pattern.rs @@ -0,0 +1,6 @@ +fn main() { + match Some(vec![3]) { + Some(vec![x]) => (), //~ ERROR unexpected `(` after qualified path + _ => (), + } +} diff --git a/src/test/ui/suggestions/vec-macro-in-pattern.stderr b/src/test/ui/suggestions/vec-macro-in-pattern.stderr new file mode 100644 index 00000000000..f94cb93a520 --- /dev/null +++ b/src/test/ui/suggestions/vec-macro-in-pattern.stderr @@ -0,0 +1,15 @@ +error: unexpected `(` after qualified path + --> $DIR/vec-macro-in-pattern.rs:3:14 + | +LL | Some(vec![x]) => (), + | ^^^^^^^ + | | + | unexpected `(` after qualified path + | in this macro invocation + | use a slice pattern here instead + | + = help: for more information, see https://doc.rust-lang.org/edition-guide/rust-2018/slice-patterns.html + = note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info) + +error: aborting due to previous error + diff --git a/src/test/ui/type/ascription/issue-47666.stderr b/src/test/ui/type/ascription/issue-47666.stderr index 965bbe5ea41..2f052341fae 100644 --- a/src/test/ui/type/ascription/issue-47666.stderr +++ b/src/test/ui/type/ascription/issue-47666.stderr @@ -6,6 +6,7 @@ LL | let _ = Option:Some(vec![0, 1]); | | | | | expected type | | in this macro invocation + | | this macro call doesn't expand to a type | help: maybe write a path separator here: `::` | = note: `#![feature(type_ascription)]` lets you annotate an expression with a type: `: `