diff --git a/src/types/chrono.rs b/src/types/chrono.rs
index 41871d2..bd23f34 100644
--- a/src/types/chrono.rs
+++ b/src/types/chrono.rs
@@ -54,10 +54,6 @@ impl FromSql for NaiveDate {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true // to avoid double check
-    }
 }
 
 /// ISO 8601 time without timezone => "HH:MM:SS.SSS"
@@ -158,10 +154,6 @@ impl FromSql for NaiveDateTime {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true // to avoid double check
-    }
 }
 
 /// ISO 8601 date and time with time zone => "YYYY-MM-DD HH:MM:SS.SSS[+-]HH:MM"
@@ -202,10 +194,6 @@ impl FromSql for DateTime<UTC> {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true // to avoid double check
-    }
 }
 
 
@@ -247,10 +235,6 @@ impl FromSql for DateTime<Local> {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true // to avoid double check
-    }
 }
 
 // struct UnixTime(NaiveDateTime);
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 4cffd50..46a5c54 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -298,10 +298,6 @@ impl FromSql for Value {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true
-    }
 }
 
 #[cfg(test)]
diff --git a/src/types/time.rs b/src/types/time.rs
index 30886a4..2fe19c5 100644
--- a/src/types/time.rs
+++ b/src/types/time.rs
@@ -42,10 +42,6 @@ impl FromSql for time::Timespec {
             _ => Err(Error::InvalidColumnType),
         }
     }
-
-    unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
-        true // to avoid double check
-    }
 }
 
 #[cfg(test)]