Lower and resolve precise captures in HIR

compiler/rustc_hir/src/hir.rs

@@ -2557,6 +2557,15 @@ pub struct OpaqueTy<'hir> {
     /// originating from a trait method. This makes it so that the opaque is
     /// lowered as an associated type.
     pub in_trait: bool,
+    /// List of arguments captured via `impl use<'a, P, ...> Trait` syntax.
+    pub precise_capturing_args: Option<&'hir [PreciseCapturingArg<'hir>]>,
+}
+
+#[derive(Debug, Clone, Copy, HashStable_Generic)]
+pub enum PreciseCapturingArg<'hir> {
+    Lifetime(&'hir Lifetime),
+    /// Non-lifetime argument (type or const)
+    Param(Res, HirId),
 }
 
 /// From whence the opaque type came.