Make a comment and add a test for one place where IsConstant is still…

… used.
google · Nov 29, 2024 · ce57dad · ce57dad
1 parent 713c194
commit ce57dad
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diff --git a/xls/dslx/frontend/parser.cc b/xls/dslx/frontend/parser.cc
@@ -1268,11 +1268,18 @@ absl::StatusOr<Expr*> Parser::ParseCast(Bindings& bindings,
     return term;
   }
 
+  // This handles the case where we're trying to make a tuple constant that has
+  // an explicitly annotated type; e.g.
+  //
+  // ```dslx
+  // const MY_TUPLE = (u32, u64):(u32:32, u64:64);
+  // ```
   if (auto* tuple = dynamic_cast<XlsTuple*>(term);
       tuple != nullptr && std::all_of(tuple->members().begin(),
                                       tuple->members().end(), IsConstant)) {
     return term;
   }
+
   return ParseErrorStatus(
       type->span(),
       "Old-style cast only permitted for constant arrays/tuples "

diff --git a/xls/dslx/type_system/typecheck_module_test.cc b/xls/dslx/type_system/typecheck_module_test.cc
@@ -282,6 +282,13 @@ fn f() -> u32 { p<u32:28>() }
   XLS_EXPECT_OK(Typecheck(kProgram));
 }
 
+TEST(TypecheckTest, TupleWithExplicitlyAnnotatedType) {
+  constexpr std::string_view kProgram = R"(
+const MY_TUPLE = (u32, u64):(u32:32, u64:64);
+)";
+  XLS_EXPECT_OK(Typecheck(kProgram));
+}
+
 TEST(TypecheckTest, ProcWithImplEmpty) {
   constexpr std::string_view kProgram = R"(
 proc Foo {}