Fix new clippy warnings

Author: sfackler

tokio-postgres/src/config.rs

@@ -489,7 +489,7 @@ impl<'a> Parser<'a> {
     }
 
     fn skip_ws(&mut self) {
-        self.take_while(|c| c.is_whitespace());
+        self.take_while(char::is_whitespace);
     }
 
     fn take_while<F>(&mut self, f: F) -> &'a str

tokio-postgres/src/error/mod.rs

@@ -413,7 +413,7 @@ impl Error {
     pub fn code(&self) -> Option<&SqlState> {
         self.source()
             .and_then(|e| e.downcast_ref::<DbError>())
-            .map(|e| e.code())
+            .map(DbError::code)
     }
 
     fn new(kind: Kind, cause: Option<Box<dyn error::Error + Sync + Send>>) -> Error {

tokio-postgres/src/proto/client.rs

@@ -154,7 +154,7 @@ impl Client {
 
     pub fn prepare(&self, name: String, query: &str, param_types: &[Type]) -> PrepareFuture {
         let pending = self.pending(|buf| {
-            frontend::parse(&name, query, param_types.iter().map(|t| t.oid()), buf)
+            frontend::parse(&name, query, param_types.iter().map(Type::oid), buf)
                 .map_err(Error::parse)?;
             frontend::describe(b'S', &name, buf).map_err(Error::parse)?;
             frontend::sync(buf);

tokio-postgres/src/types/mod.rs

@@ -386,7 +386,7 @@ impl<'a> FromSql<'a> for &'a [u8] {
 
 impl<'a> FromSql<'a> for String {
     fn from_sql(_: &Type, raw: &'a [u8]) -> Result<String, Box<dyn Error + Sync + Send>> {
-        types::text_from_sql(raw).map(|b| b.to_owned())
+        types::text_from_sql(raw).map(ToString::to_string)
     }
 
     fn accepts(ty: &Type) -> bool {