TryFrom<CassCollection> for CassCqlValue -> From

After introducing CollectionType and ensuring type safety for
collections, we can simplify the conversion from `&CassCollection` to
`CassCqlValue` by removing the `TryFrom` trait and using `From` instead.
This change reflects that the conversion is always valid as long as the
collection is well-formed.

Author: wprzytula

scylla-rust-wrapper/src/binding.rs

@@ -319,10 +319,7 @@ macro_rules! invoke_binder_maker_macro_with_type {
             $consume_v,
             $fn,
             |p: CassBorrowedSharedPtr<crate::collection::CassCollection, CConst>| {
-                match std::convert::TryInto::try_into(BoxFFI::as_ref(p).unwrap()) {
-                    Ok(v) => Ok(Some(v)),
-                    Err(_) => Err(CassError::CASS_ERROR_LIB_INVALID_VALUE_TYPE),
-                }
+                Ok(Some(std::convert::Into::into(BoxFFI::as_ref(p).unwrap())))
             },
             [p @ CassBorrowedSharedPtr<crate::collection::CassCollection, CConst>]
         );

scylla-rust-wrapper/src/collection.rs

@@ -132,16 +132,15 @@ impl CassCollection {
     }
 }
 
-impl TryFrom<&CassCollection> for CassCqlValue {
-    type Error = ();
-    fn try_from(collection: &CassCollection) -> Result<Self, Self::Error> {
+impl From<&CassCollection> for CassCqlValue {
+    fn from(collection: &CassCollection) -> Self {
         // FIXME: validate that collection items are correct
         let data_type = collection.data_type.clone();
         match collection.collection_type {
-            CollectionType::List => Ok(CassCqlValue::List {
+            CollectionType::List => CassCqlValue::List {
                 data_type,
                 values: collection.items.clone(),
-            }),
+            },
             CollectionType::Map => {
                 let mut grouped_items = Vec::new();
                 // FIXME: validate even number of items
@@ -152,15 +151,15 @@ impl TryFrom<&CassCollection> for CassCqlValue {
                     grouped_items.push((key, value));
                 }
 
-                Ok(CassCqlValue::Map {
+                CassCqlValue::Map {
                     data_type,
                     values: grouped_items,
-                })
+                }
             }
-            CollectionType::Set => Ok(CassCqlValue::Set {
+            CollectionType::Set => CassCqlValue::Set {
                 data_type,
                 values: collection.items.clone(),
-            }),
+            },
         }
     }
 }