diff --git a/prism_compile.c b/prism_compile.c
index d7eada1538..a5b1219d6c 100644
--- a/prism_compile.c
+++ b/prism_compile.c
@@ -8611,9 +8611,12 @@ pm_load_parse_file(pm_parse_result_t *result, VALUE filepath)
 VALUE
 pm_parse_string(pm_parse_result_t *result, VALUE source, VALUE filepath)
 {
-    pm_string_constant_init(&result->input, RSTRING_PTR(source), RSTRING_LEN(source));
-
     rb_encoding *encoding = rb_enc_get(source);
+    if (!rb_enc_asciicompat(encoding)) {
+        return rb_exc_new_cstr(rb_eArgError, "invalid source encoding");
+    }
+
+    pm_string_constant_init(&result->input, RSTRING_PTR(source), RSTRING_LEN(source));
     pm_options_encoding_set(&result->options, rb_enc_name(encoding));
 
     pm_options_filepath_set(&result->options, RSTRING_PTR(filepath));
diff --git a/test/.excludes-prism/TestEval.rb b/test/.excludes-prism/TestEval.rb
index 83f3e38fc9..6cc6bdfb1d 100644
--- a/test/.excludes-prism/TestEval.rb
+++ b/test/.excludes-prism/TestEval.rb
@@ -1,2 +1 @@
-exclude(:test_eval_ascii_incompatible, "incorrect encoding")
 exclude(:test_file_encoding, "incorrect encoding")