X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_middle%2Fsrc%2Fty%2Fsubst.rs;h=cf1bb5f8ac8db27900054ae4415777b520f93e52;hb=f361413cbf44ce2f144df59fc440cd484af4a56e;hp=a07582fc8ff1ec6e8a859d4642003d90806c8bd0;hpb=885bf628879310b885721e1fdd91ea2cbca9311f;p=rust.git

diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
index a07582fc8ff..cf1bb5f8ac8 100644
--- a/compiler/rustc_middle/src/ty/subst.rs
+++ b/compiler/rustc_middle/src/ty/subst.rs
@@ -758,6 +758,11 @@ pub fn subst(self, tcx: TyCtxt<'tcx>, substs: &[GenericArg<'tcx>]) -> T {
     pub fn subst_identity(self) -> T {
         self.0
     }
+
+    /// Returns the inner value, but only if it contains no bound vars.
+    pub fn no_bound_vars(self) -> Option<T> {
+        if !self.0.needs_subst() { Some(self.0) } else { None }
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////