Fix some clippy suggestions

Author: killercup

diesel_infer_schema/src/codegen.rs

@@ -35,7 +35,7 @@ pub fn infer_schema_for_schema_name(table: &TableName, database_url: &str)
      -> Result<(TableName, quote::Tokens), Box<Error>>
 {
     let mod_ident = syn::Ident::new(format!("infer_{}", table.name));
-    let table_macro = derive_infer_table_from_schema(&database_url, &table.to_string())?;
+    let table_macro = derive_infer_table_from_schema(database_url, &table.to_string())?;
     let tokens = quote! {
         mod #mod_ident {
             #table_macro

diesel_infer_schema/src/inference.rs

@@ -34,10 +34,10 @@ pub fn establish_connection(database_url: &str) -> Result<InferConnection, Box<E
     match database_url {
         #[cfg(feature = "postgres")]
         _ if database_url.starts_with("postgres://") || database_url.starts_with("postgresql://") => {
-            establish_real_connection(&database_url).map(InferConnection::Pg)
+            establish_real_connection(database_url).map(InferConnection::Pg)
         }
         #[cfg(feature = "sqlite")]
-        _ => establish_real_connection(&database_url).map(InferConnection::Sqlite),
+        _ => establish_real_connection(database_url).map(InferConnection::Sqlite),
         #[cfg(not(feature = "sqlite"))]
         _ => {
             Err(format!(

diesel_infer_schema/src/pg.rs

@@ -77,7 +77,7 @@ mod information_schema {
 }
 
 pub fn determine_column_type(attr: &ColumnInformation) -> Result<ColumnType, Box<Error>> {
-    let is_array = attr.type_name.starts_with("_");
+    let is_array = attr.type_name.starts_with('_');
     let tpe = if is_array {
         &attr.type_name[1..]
     } else {
@@ -122,7 +122,7 @@ pub fn get_primary_keys(conn: &PgConnection, table_name: &str) -> QueryResult<Ve
         .load(conn)
 }
 
-fn table_oid<'a>(table_name: &'a str) -> BoxedSelectStatement<'a, Oid, pg_class::table, Pg> {
+fn table_oid(table_name: &str) -> BoxedSelectStatement<Oid, pg_class::table, Pg> {
     use self::pg_class::dsl::*;
     use self::pg_namespace::{table as pg_namespace, oid as nsoid, nspname};