Rollup merge of #42006 - jseyfried:fix_include_regression, r=nrc

[rust.git] / src / libsyntax / ext / base.rs

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 00483b1ea5f77f0bbcdeba3a329717a0dd2ce6b6..1930f61121bb028113f2dc37d5b037f6ca9f2a47 100644 (file)
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -700,7 +700,7 @@ pub fn backtrace(&self) -> SyntaxContext {
     /// Returns span for the macro which originally caused the current expansion to happen.
     ///
     /// Stops backtracing at include! boundary.
-    pub fn expansion_cause(&self) -> Span {
+    pub fn expansion_cause(&self) -> Option<Span> {
         let mut ctxt = self.backtrace();
         let mut last_macro = None;
         loop {
@@ -716,7 +716,7 @@ pub fn expansion_cause(&self) -> Span {
                 break
             }
         }
-        last_macro.expect("missing expansion backtrace")
+        last_macro
     }
 
     pub fn struct_span_warn(&self,