diff --git a/src/types/chrono.rs b/src/types/chrono.rs
index 657baec4..0bcfe2eb 100644
--- a/src/types/chrono.rs
+++ b/src/types/chrono.rs
@@ -1,6 +1,5 @@
 extern crate chrono;
 
-use std::error;
 use std::io::prelude::*;
 use byteorder::{ReadBytesExt, WriteBytesExt, BigEndian};
 use self::chrono::{Duration, NaiveDate, NaiveTime, NaiveDateTime, DateTime, UTC, Local,
@@ -31,10 +30,7 @@ impl ToSql for NaiveDateTime {
                                  -> Result<IsNull> {
         let time = match (*self - base()).num_microseconds() {
             Some(time) => time,
-            None => {
-                let err: Box<error::Error + Sync + Send> = "value too large to transmit".into();
-                return Err(Error::Conversion(err));
-            }
+            None => return Err(Error::Conversion("value too large to transmit".into())),
         };
         try!(w.write_i64::<BigEndian>(time));
         Ok(IsNull::No)
@@ -130,8 +126,7 @@ impl ToSql for NaiveDate {
                                  -> Result<IsNull> {
         let jd = (*self - base().date()).num_days();
         if jd > i32::max_value() as i64 || jd < i32::min_value() as i64 {
-            let err: Box<error::Error + Sync + Send> = "value too large to transmit".into();
-            return Err(Error::Conversion(err));
+            return Err(Error::Conversion("value too large to transmit".into()));
         }
 
         try!(w.write_i32::<BigEndian>(jd as i32));
@@ -160,10 +155,7 @@ impl ToSql for NaiveTime {
         let delta = *self - NaiveTime::from_hms(0, 0, 0);
         let time = match delta.num_microseconds() {
             Some(time) => time,
-            None => {
-                let err: Box<error::Error + Sync + Send> = "value too large to transmit".into();
-                return Err(Error::Conversion(err));
-            }
+            None => return Err(Error::Conversion("value too large to transmit".into())),
         };
         try!(w.write_i64::<BigEndian>(time));
         Ok(IsNull::No)
diff --git a/src/types/rustc_serialize.rs b/src/types/rustc_serialize.rs
index 5c9a27e5..812b46d7 100644
--- a/src/types/rustc_serialize.rs
+++ b/src/types/rustc_serialize.rs
@@ -1,7 +1,6 @@
 extern crate rustc_serialize;
 
 use self::rustc_serialize::json;
-use std::error;
 use std::io::prelude::*;
 use byteorder::{ReadBytesExt, WriteBytesExt};
 
@@ -14,9 +13,7 @@ impl FromSql for json::Json {
         if let Type::Jsonb = *ty {
             // We only support version 1 of the jsonb binary format
             if try!(raw.read_u8()) != 1 {
-                let err: Box<error::Error + Sync + Send> = "unsupported JSONB encoding version"
-                                                               .into();
-                return Err(Error::Conversion(err));
+                return Err(Error::Conversion("unsupported JSONB encoding version".into()));
             }
         }
         json::Json::from_reader(raw).map_err(|err| Error::Conversion(Box::new(err)))
diff --git a/src/types/serde_json.rs b/src/types/serde_json.rs
index c0e21739..6e73d361 100644
--- a/src/types/serde_json.rs
+++ b/src/types/serde_json.rs
@@ -1,6 +1,5 @@
 extern crate serde_json;
 
-use std::error;
 use std::io::prelude::*;
 use byteorder::{ReadBytesExt, WriteBytesExt};
 use self::serde_json::Value;
@@ -14,9 +13,7 @@ impl FromSql for Value {
         if let Type::Jsonb = *ty {
             // We only support version 1 of the jsonb binary format
             if try!(raw.read_u8()) != 1 {
-                let err: Box<error::Error + Sync + Send> = "unsupported JSONB encoding version"
-                                                               .into();
-                return Err(Error::Conversion(err));
+                return Err(Error::Conversion("unsupported JSONB encoding version".into()));
             }
         }
         serde_json::de::from_reader(raw).map_err(|err| Error::Conversion(Box::new(err)))