Avoid expanding to unstable internal method

1 files changed, 32 insertions, 8 deletions

diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
index 30559871b4e..cdcf67b26f8 100644
--- a/compiler/rustc_expand/src/build.rs
+++ b/compiler/rustc_expand/src/build.rs
@@ -48,6 +48,23 @@ impl<'a> ExtCtxt<'a> {
         ast::Path { span, segments, tokens: None }
     }
 
+    pub fn macro_call(
+        &self,
+        span: Span,
+        path: ast::Path,
+        delim: ast::token::Delimiter,
+        tokens: ast::tokenstream::TokenStream,
+    ) -> P<ast::MacCall> {
+        P(ast::MacCall {
+            path,
+            args: P(ast::DelimArgs {
+                dspan: ast::tokenstream::DelimSpan { open: span, close: span },
+                delim,
+                tokens,
+            }),
+        })
+    }
+
     pub fn ty_mt(&self, ty: P<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy {
         ast::MutTy { ty, mutbl }
     }
@@ -265,6 +282,10 @@ impl<'a> ExtCtxt<'a> {
         self.expr(span, ast::ExprKind::Field(expr, field))
     }
 
+    pub fn expr_macro_call(&self, span: Span, call: P<ast::MacCall>) -> P<ast::Expr> {
+        self.expr(span, ast::ExprKind::MacCall(call))
+    }
+
     pub fn expr_binary(
         &self,
         sp: Span,
@@ -410,18 +431,21 @@ impl<'a> ExtCtxt<'a> {
         self.expr(sp, ast::ExprKind::Tup(exprs))
     }
 
-    pub fn expr_fail(&self, span: Span, msg: Symbol) -> P<ast::Expr> {
-        self.expr_call_global(
+    pub fn expr_unreachable(&self, span: Span) -> P<ast::Expr> {
+        self.expr_macro_call(
             span,
-            [sym::std, sym::rt, sym::begin_panic].iter().map(|s| Ident::new(*s, span)).collect(),
-            thin_vec![self.expr_str(span, msg)],
+            self.macro_call(
+                span,
+                self.path_global(
+                    span,
+                    [sym::std, sym::unreachable].map(|s| Ident::new(s, span)).to_vec(),
+                ),
+                ast::token::Delimiter::Parenthesis,
+                ast::tokenstream::TokenStream::default(),
+            ),
         )
     }
 
-    pub fn expr_unreachable(&self, span: Span) -> P<ast::Expr> {
-        self.expr_fail(span, Symbol::intern("internal error: entered unreachable code"))
-    }
-
     pub fn expr_ok(&self, sp: Span, expr: P<ast::Expr>) -> P<ast::Expr> {
         let ok = self.std_path(&[sym::result, sym::Result, sym::Ok]);
         self.expr_call_global(sp, ok, thin_vec![expr])