Use the Self keyword where applicable.

https://github.com/rust-lang-nursery/rust-clippy/wiki#use_self

lib/wasm/src/code_translator.rs

@@ -144,8 +144,8 @@ pub struct FunctionImports {
 }
 
 impl FunctionImports {
-    fn new() -> FunctionImports {
-        FunctionImports {
+    fn new() -> Self {
+        Self {
             functions: HashMap::new(),
             signatures: HashMap::new(),
         }

lib/wasm/src/module_translator.rs

@@ -46,8 +46,8 @@ pub struct ImportMappings {
 
 impl ImportMappings {
     /// Create a new empty `ImportMappings`.
-    pub fn new() -> ImportMappings {
-        ImportMappings {
+    pub fn new() -> Self {
+        Self {
             functions: HashMap::new(),
             signatures: HashMap::new(),
         }

lib/wasm/src/runtime/dummy.rs

@@ -15,8 +15,8 @@ pub struct DummyRuntime {
 
 impl DummyRuntime {
     /// Allocates the runtime data structures.
-    pub fn new() -> DummyRuntime {
-        DummyRuntime { globals: Vec::new() }
+    pub fn new() -> Self {
+        Self { globals: Vec::new() }
     }
 }
 

lib/wasm/src/translation_utils.rs

@@ -98,7 +98,7 @@ impl cretonne::entity::EntityRef for Local {
     }
 }
 impl Default for Local {
-    fn default() -> Local {
+    fn default() -> Self {
         Local(u32::MAX)
     }
 }