diff --git a/craft_grammar/models.py b/craft_grammar/models.py
index 8233a93..b824369 100644
--- a/craft_grammar/models.py
+++ b/craft_grammar/models.py
@@ -121,36 +121,33 @@ def _validate_grammar_list(  # noqa: PLR0912
                     pass
                 else:
                     continue
-            if issubclass(type_, str):
-                if isinstance(item, dict):
-                    errors.append(
-                        pydantic_core.InitErrorDetails(
-                            type="value_error",
-                            loc=(index,),
-                            input=item,
-                            ctx={
-                                "error": ValueError(
-                                    f"value must be a str or valid grammar dict: {input_value!r}",
-                                ),
-                            },
-                        ),
-                    )
-                else:
-                    raise pydantic.ValidationError.from_exception_data(
-                        title=f"Grammar[{type_.__name__}]",
-                        line_errors=[
-                            pydantic_core.InitErrorDetails(
-                                type="string_type",
-                                loc=(),
-                                input=item,
-                            ),
-                        ],
-                    )
-                    break
-            else:
+            if not issubclass(type_, str):
                 raise ValueError(  # noqa: TRY004
                     _format_type_error(type_, input_value),
                 )
+            if not isinstance(item, dict):
+                raise pydantic.ValidationError.from_exception_data(
+                    title=f"Grammar[{type_.__name__}]",
+                    line_errors=[
+                        pydantic_core.InitErrorDetails(
+                            type="string_type",
+                            loc=(),
+                            input=item,
+                        ),
+                    ],
+                )            
+            errors.append(
+                pydantic_core.InitErrorDetails(
+                    type="value_error",
+                    loc=(index,),
+                    input=item,
+                    ctx={
+                        "error": ValueError(
+                            f"value must be a str or valid grammar dict: {input_value!r}",
+                        ),
+                    },
+                ),
+            )
 
         if errors:
             raise pydantic.ValidationError.from_exception_data(