fix var name

Author: Arttu Voutilainen

datafusion/substrait/src/logical_plan/consumer.rs

@@ -894,7 +894,7 @@ pub async fn from_substrait_rex(
         Some(RexType::ScalarFunction(f)) => {
             let fn_name = extensions.get(&f.function_reference).ok_or_else(|| {
                 DataFusionError::NotImplemented(format!(
-                    "Aggregated function not found: function reference = {:?}",
+                    "Scalar function not found: function reference = {:?}",
                     f.function_reference
                 ))
             })?;
@@ -912,8 +912,8 @@ pub async fn from_substrait_rex(
                         Some(ArgType::Value(e)) => {
                             from_substrait_rex(ctx, e, input_schema, extensions).await
                         }
-                        _ => not_impl_err!(
-                            "Aggregated function argument non-Value type not supported"
+                        t => not_impl_err!(
+                            "Only Value arguments are supported for scalar functions, got: {t:?}"
                         ),
                     }?;
                     args.push(arg_expr.as_ref().clone());
@@ -938,7 +938,7 @@ pub async fn from_substrait_rex(
                 ScalarFunctionType::Op(op) => {
                     if f.arguments.len() != 2 {
                         return not_impl_err!(
-                            "Expect two arguments for binary operator {op:?}"
+                            "Expected two arguments for binary operator {op:?}"
                         );
                     }
                     let lhs = &f.arguments[0].arg_type;
@@ -1464,13 +1464,15 @@ fn from_substrait_literal_with_type(
             }?;
             let builder = s.fields.iter().zip(fields).try_fold(
                 ScalarStructBuilder::new(),
-                |b, (sv, field)| -> Result<_> {
+                |b, (lit, field)| -> Result<_> {
                     let sv = from_substrait_literal_with_type(
-                        sv,
+                        lit,
                         field.to_owned().map(|f| f.data_type().to_owned()).as_ref(),
                     )?;
                     Ok(b.with_scalar(
-                        field.unwrap_or_else(|| Field::new("col", sv.data_type(), true)),
+                        field.unwrap_or_else(|| {
+                            Field::new("col", sv.data_type(), lit.nullable)
+                        }),
                         sv,
                     ))
                 },