diff --git a/resources/parametrize/errors.rs b/resources/parametrize/errors.rs
index 4ec9d2af..4d43bb70 100644
--- a/resources/parametrize/errors.rs
+++ b/resources/parametrize/errors.rs
@@ -15,3 +15,10 @@ fn error_fixture_wrong_type(fixture: String, f: u32) {}
 
 #[rstest_parametrize(f, case(42))]
 fn error_param_wrong_type(f: &str) {}
+
+#[rstest_parametrize(condition,
+    case(r(r#"vec![1,2,3].contains(2)"#)))
+]
+fn example(condition: bool) {
+    assert!(condition)
+}
diff --git a/src/lib.rs b/src/lib.rs
index 74b95850..279e027b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -87,14 +87,6 @@ fn respan<T: Into<proc_macro2::TokenTree>>(t: T, span: Span) -> proc_macro2::Tok
     t
 }
 
-fn respan_stream(t: proc_macro2::TokenStream, span: Span) -> proc_macro2::TokenStream {
-    t.into_iter().map(|tt| respan(tt, span)).collect()
-}
-
-fn is_arbitrary_rust_code(meta: &MetaList) -> bool {
-    ["Unwrap", "r"].iter().any(|&n| meta.ident == n)
-}
-
 fn parse_case_arg(a: &NestedMeta) -> Result<CaseArg, Error> {
     match a {
         NestedMeta::Literal(l) =>
@@ -104,7 +96,7 @@ fn parse_case_arg(a: &NestedMeta) -> Result<CaseArg, Error> {
                 Meta::List(arg) if is_arbitrary_rust_code(arg) =>
                     match arg.nested.first().unwrap().value() {
                         NestedMeta::Literal(Lit::Str(inner_unwrap)) =>
-                            parse_expression(inner_unwrap.value()),
+                            inner_unwrap.parse().or(Err(format!("Cannot parse '{}'", inner_unwrap.value()))),
                         _ => panic!("Unexpected case argument: {:?}", opt),
                     },
                 Meta::Word(term) => {
@@ -113,11 +105,8 @@ fn parse_case_arg(a: &NestedMeta) -> Result<CaseArg, Error> {
                 nested_case => panic!("Unexpected case attribute: {:?}", nested_case)
             }
         }
-    }.map(|t|
-        {
-            let e = respan_stream(t.into_token_stream(), a.span());
-            CaseArg::from(syn::parse2::<Expr>(e).unwrap()).respan(a.span())
-        }).map_err(|m| Error::new(a.span(), m))
+    }.map(|t| CaseArg::from(t).respan(a.span()))
+        .map_err(|m| Error::new(a.span(), m))
 }
 
 trait TryFrom<T>: Sized
diff --git a/tests/parametrize.rs b/tests/parametrize.rs
index 1a58f16c..cf0071a7 100644
--- a/tests/parametrize.rs
+++ b/tests/parametrize.rs
@@ -162,9 +162,6 @@ mod not_compile_if_missed_arguments {
 mod not_compile_if_a_case_has_a_wrong_signature {
     use super::*;
 
-    //  TODO:
-    // - [ ] Test case for less case args
-
     #[test]
     fn with_too_much_arguments() {
         let (output, _) = run_test("case_with_too_much_args.rs");
@@ -293,17 +290,35 @@ mod dump_input_values {
     }
 }
 
-#[test]
-fn should_show_correct_errors() {
-    let (output, name) = run_test("errors.rs");
+mod should_show_correct_errors {
+    use super::*;
+    use lazy_static::lazy_static;
+    use std::process::Output;
+
+    fn execute() -> &'static (Output, String) {
+        lazy_static! {
+            static ref OUTPUT: (Output, String) =
+                run_test("errors.rs");
+        }
+        &OUTPUT
+    }
 
-    assert_in!(output.stderr.str(), format!("
+    #[test]
+    fn if_no_fixture() {
+        let (output, name) = execute();
+
+        assert_in!(output.stderr.str(), format!("
         error[E0425]: cannot find function `no_fixture` in this scope
           --> {}/src/lib.rs:10:1
            |
         10 | #[rstest_parametrize(f, case(42))]", name).deindent());
+    }
+
+    #[test]
+    fn if_wrong_type() {
+        let (output, name) = execute();
 
-    assert_in!(output.stderr.str(), format!(r#"
+        assert_in!(output.stderr.str(), format!(r#"
         error[E0308]: mismatched types
          --> {}/src/lib.rs:7:18
           |
@@ -313,8 +328,13 @@ fn should_show_correct_errors() {
           = note: expected type `u32`
                      found type `&'static str`
         "#, name).deindent());
+    }
 
-    assert_in!(output.stderr.str(), format!("
+    #[test]
+    fn if_wrong_type_fixture() {
+        let (output, name) = execute();
+
+        assert_in!(output.stderr.str(), format!("
         error[E0308]: mismatched types
           --> {}/src/lib.rs:14:29
            |
@@ -327,12 +347,37 @@ fn should_show_correct_errors() {
            = note: expected type `std::string::String`
                       found type `u32`
         ", name).deindent());
+    }
 
-    assert_in!(output.stderr.str(), format!("
+    #[test]
+    fn if_wrong_type_param() {
+        let (output, name) = execute();
+
+        assert_in!(output.stderr.str(), format!("
         error[E0308]: mismatched types
           --> {}/src/lib.rs:17:27
            |
         17 | fn error_param_wrong_type(f: &str) {{}}", name).deindent());
+    }
+
+    #[test]
+    fn if_arbitrary_rust_code_has_some_errors() {
+        let (output, name) = execute();
+
+        assert_in!(output.stderr.str(), format!(r##"
+        error[E0308]: mismatched types
+          --> {}/src/lib.rs:20:12
+           |
+        20 |     case(r(r#"vec![1,2,3].contains(2)"#)))
+           |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+           |            |
+           |            expected &{{integer}}, found integer
+           |            help: consider borrowing here: `&r#"vec![1,2,3].contains(2)"#`
+           |
+           = note: expected type `&{{integer}}`
+                      found type `{{integer}}`"##,
+                      name).deindent());
+    }
 }
 
 #[test]