[DSLX:TS] Fix TypeMissingInfo ICE where a builtin parametric fn wasn'…

…t invoked.

Found via coverage-guided fuzzing.

PiperOrigin-RevId: 596748305

xls/dslx/BUILD

@@ -352,10 +352,12 @@ cc_library(
     srcs = ["dslx_builtins.cc"],
     hdrs = ["dslx_builtins.h"],
     deps = [
+        ":channel_direction",
         ":errors",
         ":interp_value",
         "//xls/common/logging",
         "//xls/common/status:status_macros",
+        "//xls/dslx/frontend:ast",
         "//xls/dslx/frontend:ast_node",
         "//xls/dslx/frontend:builtins_metadata",
         "//xls/dslx/frontend:pos",

xls/dslx/dslx_builtins.cc

@@ -21,7 +21,6 @@
 #include <string>
 #include <string_view>
 #include <utility>
-#include <variant>
 #include <vector>
 
 #include "absl/container/flat_hash_map.h"
@@ -33,7 +32,9 @@
 #include "absl/types/span.h"
 #include "xls/common/logging/logging.h"
 #include "xls/common/status/status_macros.h"
+#include "xls/dslx/channel_direction.h"
 #include "xls/dslx/errors.h"
+#include "xls/dslx/frontend/ast.h"
 #include "xls/dslx/frontend/ast_node.h"
 #include "xls/dslx/frontend/builtins_metadata.h"
 #include "xls/dslx/frontend/pos.h"

xls/dslx/dslx_builtins.h

@@ -26,6 +26,9 @@
 
 #include "absl/container/flat_hash_set.h"
 #include "absl/status/statusor.h"
+#include "xls/dslx/frontend/ast.h"
+#include "xls/dslx/frontend/pos.h"
+#include "xls/dslx/interp_value.h"
 #include "xls/dslx/type_system/concrete_type.h"
 #include "xls/dslx/type_system/deduce_ctx.h"
 #include "xls/dslx/type_system/parametric_constraint.h"
@@ -81,6 +84,10 @@ using SignatureFn = std::function<absl::StatusOr<TypeAndParametricEnv>(
 absl::StatusOr<SignatureFn> GetParametricBuiltinSignature(
     std::string_view builtin_name);
 
+// Wrapper around the above that checks whether name_ref refers to a builtin
+// name def and whether that builtin name is a parametric function.
+bool IsBuiltinParametricNameRef(const NameRef* name_ref);
+
 }  // namespace xls::dslx
 
 #endif  // XLS_DSLX_DSLX_BUILTINS_H_

xls/dslx/frontend/BUILD

@@ -109,6 +109,7 @@ cc_library(
         "//xls/common/status:ret_check",
         "//xls/common/status:status_builder",
         "//xls/common/status:status_macros",
+        "//xls/dslx:channel_direction",
         "//xls/ir:code_template",
         "//xls/ir:foreign_function",
         "//xls/ir:format_strings",
@@ -163,6 +164,7 @@ cc_library(
         "//xls/common/status:status_macros",
         "//xls/dslx:import_data",
         "//xls/dslx:interp_value",
+        "//xls/dslx/frontend:builtins_metadata",
         "//xls/dslx/type_system:type_info",
     ],
 )
@@ -286,6 +288,7 @@ cc_library(
     hdrs = ["bindings.h"],
     deps = [
         ":ast",
+        ":pos",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/status",

xls/dslx/frontend/ast_utils.cc

@@ -35,8 +35,10 @@
 #include "xls/common/status/status_macros.h"
 #include "xls/common/visitor.h"
 #include "xls/dslx/frontend/ast.h"
+#include "xls/dslx/frontend/builtins_metadata.h"
 #include "xls/dslx/frontend/token_utils.h"
 #include "xls/dslx/import_data.h"
+#include "xls/dslx/interp_value.h"
 #include "xls/dslx/type_system/type_info.h"
 
 namespace xls::dslx {
@@ -651,4 +653,12 @@ absl::StatusOr<std::vector<const NameDef*>> CollectReferencedUnder(
   return name_defs;
 }
 
+bool IsBuiltinParametricNameRef(const NameRef* name_ref) {
+  // Implementation note: we also check IsNameParametricBuiltin() as future
+  // proofing -- we may add a built-in name that is not a type or parametric
+  // function.
+  return std::holds_alternative<BuiltinNameDef*>(name_ref->name_def()) &&
+         IsNameParametricBuiltin(name_ref->identifier());
+}
+
 }  // namespace xls::dslx

xls/dslx/frontend/ast_utils.h

@@ -233,6 +233,10 @@ absl::StatusOr<std::vector<const AstNode*>> CollectUnder(const AstNode* root,
 absl::StatusOr<std::vector<const NameDef*>> CollectReferencedUnder(
     const AstNode* root, bool want_types = false);
 
+// Wrapper around the above that checks whether name_ref refers to a builtin
+// name def and whether that builtin name is a parametric function.
+bool IsBuiltinParametricNameRef(const NameRef* name_ref);
+
 }  // namespace xls::dslx
 
 #endif  // XLS_DSLX_FRONTEND_AST_UTILS_H_

xls/dslx/frontend/bindings.h

@@ -33,6 +33,7 @@
 #include "absl/strings/str_format.h"
 #include "xls/common/logging/logging.h"
 #include "xls/dslx/frontend/ast.h"
+#include "xls/dslx/frontend/pos.h"
 
 namespace xls::dslx {
 

xls/dslx/frontend/parser.cc

@@ -18,6 +18,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <functional>
+#include <initializer_list>
 #include <memory>
 #include <optional>
 #include <string>
@@ -43,6 +44,7 @@
 #include "xls/common/status/status_builder.h"
 #include "xls/common/status/status_macros.h"
 #include "xls/common/visitor.h"
+#include "xls/dslx/channel_direction.h"
 #include "xls/dslx/frontend/ast.h"
 #include "xls/dslx/frontend/ast_cloner.h"
 #include "xls/dslx/frontend/ast_utils.h"

xls/dslx/type_system/BUILD

@@ -133,6 +133,7 @@ cc_library(
         "//xls/ir:bits",
         "//xls/ir:bits_ops",
         "//xls/ir:format_preference",
+        "//xls/ir:format_strings",
     ],
 )
 

xls/dslx/type_system/concrete_type.h

@@ -40,6 +40,7 @@
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
 #include "absl/types/span.h"
+#include "xls/common/logging/logging.h"
 #include "xls/dslx/channel_direction.h"
 #include "xls/dslx/frontend/ast.h"
 #include "xls/dslx/interp_value.h"

xls/dslx/type_system/deduce.cc

@@ -71,6 +71,7 @@
 #include "xls/ir/bits.h"
 #include "xls/ir/bits_ops.h"
 #include "xls/ir/format_preference.h"
+#include "xls/ir/format_strings.h"
 
 namespace xls::dslx {
 namespace {
@@ -3239,7 +3240,8 @@ absl::StatusOr<std::unique_ptr<ConcreteType>> DeduceNameRef(const NameRef* node,
   // If this has no corresponding type because it is a parametric function that
   // is not being invoked, we give an error instead of propagating
   // "TypeMissing".
-  if (IsParametricFunction(node->GetDefiner()) &&
+  if ((IsParametricFunction(node->GetDefiner()) ||
+       IsBuiltinParametricNameRef(node)) &&
       !ParentIsInvocationWithCallee(node)) {
     return TypeInferenceErrorStatus(
         node->span(), nullptr,

xls/dslx/type_system/typecheck_test.cc

@@ -2204,5 +2204,15 @@ fn f(x: Point1D) -> Point1D { x }
                  HasSubstr("Parametric type being returned from function")));
 }
 
+TEST(TypecheckErrorTest, OperatorOnParametricBuiltin) {
+  EXPECT_THAT(Typecheck(R"(
+fn f() { fail!%2 }
+)")
+                  .status(),
+              IsPosError("TypeInferenceError",
+                         HasSubstr("Name 'fail!' is a parametric function, but "
+                                   "it is not being invoked")));
+}
+
 }  // namespace
 }  // namespace xls::dslx