Rollup merge of #68818 - matthiaskrgr:misc_perf, r=Mark-Simulacrum

[rust.git] / src / librustc_expand / expand.rs

diff --git a/src/librustc_expand/expand.rs b/src/librustc_expand/expand.rs
index 35b6b96d49b397cd8469ffa7ff506d08e20372cc..0b8cbd3a7833301e861501af778423255aa1b99a 100644 (file)
--- a/src/librustc_expand/expand.rs
+++ b/src/librustc_expand/expand.rs
@@ -5,6 +5,7 @@
 use crate::placeholders::{placeholder, PlaceholderExpander};
 use crate::proc_macro::collect_derives;
 
+use rustc_ast_pretty::pprust;
 use rustc_attr::{self as attr, is_builtin_attr, HasAttrs};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{Applicability, FatalError, PResult};
@@ -13,15 +14,14 @@
 use rustc_parse::parser::Parser;
 use rustc_parse::validate_attr;
 use rustc_parse::DirectoryOwnership;
+use rustc_session::parse::{feature_err, ParseSess};
 use rustc_span::source_map::respan;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{FileName, Span, DUMMY_SP};
 use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
 use syntax::ast::{ItemKind, MacArgs, MacStmtStyle, StmtKind};
 use syntax::mut_visit::*;
-use syntax::print::pprust;
 use syntax::ptr::P;
-use syntax::sess::{feature_err, ParseSess};
 use syntax::token;
 use syntax::tokenstream::{TokenStream, TokenTree};
 use syntax::util::map_in_place::MapInPlace;
@@ -363,7 +363,17 @@ pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
                 krate.attrs = vec![];
                 krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
             }
-            _ => unreachable!(),
+            Some(ast::Item { span, kind, .. }) => {
+                krate.attrs = vec![];
+                krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
+                self.cx.span_err(
+                    span,
+                    &format!(
+                        "expected crate top-level item to be a module after macro expansion, found a {}",
+                        kind.descriptive_variant()
+                    ),
+                );
+            }
         };
         self.cx.trace_macros_diag();
         krate