diff --git a/sqlx-core/src/mysql/types/bigdecimal.rs b/sqlx-core/src/mysql/types/bigdecimal.rs
index 4be6c324..c5461f20 100644
--- a/sqlx-core/src/mysql/types/bigdecimal.rs
+++ b/sqlx-core/src/mysql/types/bigdecimal.rs
@@ -151,24 +151,24 @@ impl Decode<'_, MySql> for BigDecimal {
 fn test_encode_decimal() {
     let v = BigDecimal::new(BigInt::from(-105), 2);
     let mut buf: Vec<u8> = vec![];
-    v.encode(&mut buf);
+    <BigDecimal as Encode<MySql>>::encode(&v, &mut buf);
     assert_eq!(buf, vec![0x05, 0x2D, 0x31, 0x2E, 0x30, 0x35]);
 
     let v = BigDecimal::new(BigInt::from(-105), -3);
     let mut buf: Vec<u8> = vec![];
-    v.encode(&mut buf);
+    <BigDecimal as Encode<MySql>>::encode(&v, &mut buf);
     assert_eq!(buf, vec![0x07, 0x2D, 0x31, 0x30, 0x35, 0x30, 0x30, 0x30]);
 
     let v = BigDecimal::new(BigInt::from(105), 5);
     let mut buf: Vec<u8> = vec![];
-    v.encode(&mut buf);
+    <BigDecimal as Encode<MySql>>::encode(&v, &mut buf);
     assert_eq!(buf, vec![0x07, 0x30, 0x2E, 0x30, 0x30, 0x31, 0x30, 0x35]);
 }
 
 #[test]
 fn test_decode_decimal() {
     let buf: Vec<u8> = vec![0x05, 0x2D, 0x31, 0x2E, 0x30, 0x35];
-    let v = BigDecimal::decode(MySqlValue::binary(
+    let v = <BigDecimal as Decode<'_, MySql>>::decode(MySqlValue::binary(
         MySqlTypeInfo::new(TypeId::NEWDECIMAL),
         buf.as_slice(),
     ))
@@ -176,7 +176,7 @@ fn test_decode_decimal() {
     assert_eq!(v.to_string(), "-1.05");
 
     let buf: Vec<u8> = vec![0x04, 0x30, 0x2E, 0x30, 0x35];
-    let v = BigDecimal::decode(MySqlValue::binary(
+    let v = <BigDecimal as Decode<'_, MySql>>::decode(MySqlValue::binary(
         MySqlTypeInfo::new(TypeId::NEWDECIMAL),
         buf.as_slice(),
     ))
@@ -184,7 +184,7 @@ fn test_decode_decimal() {
     assert_eq!(v.to_string(), "0.05");
 
     let buf: Vec<u8> = vec![0x06, 0x2D, 0x39, 0x30, 0x30, 0x30, 0x30];
-    let v = BigDecimal::decode(MySqlValue::binary(
+    let v = <BigDecimal as Decode<'_, MySql>>::decode(MySqlValue::binary(
         MySqlTypeInfo::new(TypeId::NEWDECIMAL),
         buf.as_slice(),
     ))