diff options
Diffstat (limited to 'compiler/rustc_expand/src/mbe')
| -rw-r--r-- | compiler/rustc_expand/src/mbe/diagnostics.rs | 41 | ||||
| -rw-r--r-- | compiler/rustc_expand/src/mbe/metavar_expr.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_expand/src/mbe/transcribe.rs | 2 |
3 files changed, 34 insertions, 11 deletions
diff --git a/compiler/rustc_expand/src/mbe/diagnostics.rs b/compiler/rustc_expand/src/mbe/diagnostics.rs index f469b2dae..355722922 100644 --- a/compiler/rustc_expand/src/mbe/diagnostics.rs +++ b/compiler/rustc_expand/src/mbe/diagnostics.rs @@ -1,12 +1,10 @@ -use std::borrow::Cow; - use crate::base::{DummyResult, ExtCtxt, MacResult}; use crate::expand::{parse_ast_fragment, AstFragmentKind}; use crate::mbe::{ macro_parser::{MatcherLoc, NamedParseResult, ParseResult::*, TtParser}, macro_rules::{try_match_macro, Tracker}, }; -use rustc_ast::token::{self, Token}; +use rustc_ast::token::{self, Token, TokenKind}; use rustc_ast::tokenstream::TokenStream; use rustc_ast_pretty::pprust; use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, DiagnosticMessage}; @@ -14,6 +12,7 @@ use rustc_parse::parser::{Parser, Recovery}; use rustc_span::source_map::SourceMap; use rustc_span::symbol::Ident; use rustc_span::Span; +use std::borrow::Cow; use super::macro_rules::{parser_from_cx, NoopTracker}; @@ -63,6 +62,18 @@ pub(super) fn failed_to_match_macro<'cx>( err.note(format!("while trying to match {remaining_matcher}")); } + if let MatcherLoc::Token { token: expected_token } = &remaining_matcher + && (matches!(expected_token.kind, TokenKind::Interpolated(_)) + || matches!(token.kind, TokenKind::Interpolated(_))) + { + err.note("captured metavariables except for `:tt`, `:ident` and `:lifetime` cannot be compared to other tokens"); + err.note("see <https://doc.rust-lang.org/nightly/reference/macros-by-example.html#forwarding-a-matched-fragment> for more information"); + + if !def_span.is_dummy() && !cx.source_map().is_imported(def_span) { + err.help("try using `:tt` instead in the macro definition"); + } + } + // Check whether there's a missing comma in this macro call, like `println!("{}" a);` if let Some((arg, comma_span)) = arg.add_comma() { for lhs in lhses { @@ -239,12 +250,24 @@ pub(super) fn emit_frag_parse_err( e.note( "the macro call doesn't expand to an expression, but it can expand to a statement", ); - e.span_suggestion_verbose( - site_span.shrink_to_hi(), - "add `;` to interpret the expansion as a statement", - ";", - Applicability::MaybeIncorrect, - ); + + if parser.token == token::Semi { + if let Ok(snippet) = parser.sess.source_map().span_to_snippet(site_span) { + e.span_suggestion_verbose( + site_span, + "surround the macro invocation with `{}` to interpret the expansion as a statement", + format!("{{ {}; }}", snippet), + Applicability::MaybeIncorrect, + ); + } + } else { + e.span_suggestion_verbose( + site_span.shrink_to_hi(), + "add `;` to interpret the expansion as a statement", + ";", + Applicability::MaybeIncorrect, + ); + } } }, _ => annotate_err_with_kind(&mut e, kind, site_span), diff --git a/compiler/rustc_expand/src/mbe/metavar_expr.rs b/compiler/rustc_expand/src/mbe/metavar_expr.rs index de34df011..fb3a00d86 100644 --- a/compiler/rustc_expand/src/mbe/metavar_expr.rs +++ b/compiler/rustc_expand/src/mbe/metavar_expr.rs @@ -41,7 +41,7 @@ impl MetaVarExpr { }; check_trailing_token(&mut tts, sess)?; let mut iter = args.trees(); - let rslt = match &*ident.as_str() { + let rslt = match ident.as_str() { "count" => parse_count(&mut iter, sess, ident.span)?, "ignore" => MetaVarExpr::Ignore(parse_ident(&mut iter, sess, ident.span)?), "index" => MetaVarExpr::Index(parse_depth(&mut iter, sess, ident.span)?), diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs index 47a8b4bc4..a07cb6517 100644 --- a/compiler/rustc_expand/src/mbe/transcribe.rs +++ b/compiler/rustc_expand/src/mbe/transcribe.rs @@ -367,7 +367,7 @@ impl LockstepIterSize { /// /// Example: `$($($x $y)+*);+` -- we need to make sure that `x` and `y` repeat the same amount as /// each other at the given depth when the macro was invoked. If they don't it might mean they were -/// declared at unequal depths or there was a compile bug. For example, if we have 3 repetitions of +/// declared at depths which weren't equal or there was a compiler bug. For example, if we have 3 repetitions of /// the outer sequence and 4 repetitions of the inner sequence for `x`, we should have the same for /// `y`; otherwise, we can't transcribe them both at the given depth. fn lockstep_iter_size( |