Enable and fix several more clippy lints.

lib/frontend/src/frontend.rs

@@ -238,9 +238,9 @@ where
     ) -> FunctionBuilder<'a, Variable> {
         debug_assert!(func_ctx.is_empty());
         FunctionBuilder {
-            func: func,
+            func,
             srcloc: Default::default(),
-            func_ctx: func_ctx,
+            func_ctx,
             position: Position::default(),
         }
     }

lib/frontend/src/lib.rs

@@ -128,7 +128,18 @@
 //! ```
 
 #![deny(missing_docs, trivial_numeric_casts, unused_extern_crates)]
-#![cfg_attr(feature = "cargo-clippy", allow(new_without_default, redundant_field_names))]
+#![warn(unused_import_braces, unstable_features)]
+#![cfg_attr(feature = "cargo-clippy", allow(new_without_default))]
+#![cfg_attr(feature="cargo-clippy", warn(
+                float_arithmetic,
+                mut_mut,
+                nonminimal_bool,
+                option_map_unwrap_or,
+                option_map_unwrap_or_else,
+                print_stdout,
+                unicode_not_nfc,
+                use_self,
+                ))]
 
 extern crate cretonne_codegen;
 

lib/frontend/src/ssa.rs

@@ -361,7 +361,7 @@ where
         let block = self.blocks.push(BlockData::EbbHeader(EbbHeaderBlockData {
             predecessors: Vec::new(),
             sealed: false,
-            ebb: ebb,
+            ebb,
             undef_variables: Vec::new(),
         }));
         self.ebb_headers[ebb] = block.into();