[Demangle][Rust] Parse slice type

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D102578

Author: tmiasko

llvm/lib/Demangle/RustDemangle.cpp

@@ -436,6 +436,11 @@ void Demangler::demangleType() {
     demangleConst();
     print("]");
     break;
+  case 'S':
+    print("[");
+    demangleType();
+    print("]");
+    break;
   default:
     Position = Start;
     demanglePath(InType::Yes);

llvm/test/Demangle/rust.test

@@ -160,6 +160,9 @@ CHECK: named::<Name<>>
 CHECK: types::<[u8; 0]>
        _RIC5typesAhj0_E
 
+CHECK: types::<[_]>
+       _RIC5typesSpE
+
 ; Integer constants. Test value demangling.
 
 CHECK: integer::<0>