Minor fixes to prevent warnings for Rust 2021 (bytecodealliance#255)

* Minor fixes to prevent warnings related to Rust 2021 in the tests
* Remove unnecessary references
* Silence clippy

Co-authored-by: Sergei Shulepov <sergei@parity.io>

src/func.rs

@@ -139,7 +139,7 @@ impl FuncInstance {
         args: &[RuntimeValue],
         externals: &mut E,
     ) -> Result<Option<RuntimeValue>, Trap> {
-        check_function_args(func.signature(), &args)?;
+        check_function_args(func.signature(), args)?;
         match *func.as_internal() {
             FuncInstanceInternal::Internal { .. } => {
                 let mut interpreter = Interpreter::new(func, args, None)?;
@@ -165,7 +165,7 @@ impl FuncInstance {
         externals: &mut E,
         stack_recycler: &mut StackRecycler,
     ) -> Result<Option<RuntimeValue>, Trap> {
-        check_function_args(func.signature(), &args)?;
+        check_function_args(func.signature(), args)?;
         match *func.as_internal() {
             FuncInstanceInternal::Internal { .. } => {
                 let mut interpreter = Interpreter::new(func, args, Some(stack_recycler))?;

src/memory/mod.rs

@@ -537,7 +537,7 @@ impl MemoryInstance {
     ///
     /// [`set`]: #method.get
     /// [`clear`]: #method.set
-    #[allow(clippy::clippy::needless_lifetimes)]
+    #[allow(clippy::needless_lifetimes)]
     pub fn direct_access<'a>(&'a self) -> impl AsRef<[u8]> + 'a {
         struct Buffer<'a>(Ref<'a, ByteBuf>);
         impl<'a> AsRef<[u8]> for Buffer<'a> {
@@ -558,7 +558,7 @@ impl MemoryInstance {
     ///
     /// [`get`]: #method.get
     /// [`set`]: #method.set
-    #[allow(clippy::clippy::needless_lifetimes)]
+    #[allow(clippy::needless_lifetimes)]
     pub fn direct_access_mut<'a>(&'a self) -> impl AsMut<[u8]> + 'a {
         struct Buffer<'a>(RefMut<'a, ByteBuf>);
         impl<'a> AsMut<[u8]> for Buffer<'a> {

src/nan_preserving_float.rs

@@ -96,6 +96,8 @@ macro_rules! float {
             }
         }
 
+        // clippy suggestion would fail some tests
+        #[allow(clippy::cmp_owned)]
         impl<T: Into<$for> + Copy> PartialEq<T> for $for {
             fn eq(&self, other: &T) -> bool {
                 $is::from(*self) == $is::from((*other).into())

src/prepare/compile.rs

@@ -1246,7 +1246,7 @@ impl Sink {
 
         // Patch all relocations that was previously recorded for this
         // particular label.
-        let unresolved_rels = mem::replace(&mut self.labels[label.0].1, Vec::new());
+        let unresolved_rels = mem::take(&mut self.labels[label.0].1);
         for reloc in unresolved_rels {
             self.ins.patch_relocation(reloc, dst_pc);
         }

src/types.rs

@@ -49,7 +49,7 @@ impl Signature {
 
     /// Returns parameter types of this signature.
     pub fn params(&self) -> &[ValueType] {
-        &self.params.as_ref()
+        self.params.as_ref()
     }
 
     /// Returns return type of this signature.

tests/spec/run.rs

@@ -491,7 +491,7 @@ fn try_spec(name: &str) -> Result<(), Error> {
         for err in errors {
             write!(out, "{}", err).expect("Error formatting errors");
         }
-        panic!(out);
+        panic!("{}", out);
     }
 
     Ok(())

validation/src/func.rs

@@ -96,7 +96,7 @@ pub fn drive<T: FuncValidator>(
     }
 
     let mut context = FunctionValidationContext::new(
-        &module,
+        module,
         Locals::new(params, body.locals())?,
         DEFAULT_VALUE_STACK_LIMIT,
         DEFAULT_FRAME_STACK_LIMIT,
@@ -237,6 +237,8 @@ impl<'a> FunctionValidationContext<'a> {
                     top.block_type
                 };
 
+                // Ignore clippy as pop(..) != pop(..) + push_value(..) under some conditions
+                #[allow(clippy::branches_sharing_code)]
                 if self.frame_stack.len() == 1 {
                     // We are about to close the last frame.
 
@@ -860,7 +862,7 @@ impl<'a> FunctionValidationContext<'a> {
             &self.frame_stack,
             StackValueType::Any,
         )?;
-        if StackValueType::from(local_type) != value_type {
+        if local_type != value_type {
             return Err(Error(format!(
                 "Trying to update local {} of type {:?} with value of type {:?}",
                 index, local_type, value_type

validation/src/lib.rs

@@ -126,7 +126,7 @@ impl FuncValidator for PlainFuncValidator {
 pub fn validate_module<V: Validator>(module: &Module) -> Result<V::Output, Error> {
     let mut context_builder = ModuleContextBuilder::new();
     let mut imported_globals = Vec::new();
-    let mut validation = V::new(&module);
+    let mut validation = V::new(module);
 
     // Copy types from module as is.
     context_builder.set_types(
@@ -311,7 +311,7 @@ pub fn validate_module<V: Validator>(module: &Module) -> Result<V::Output, Error
                 .offset()
                 .as_ref()
                 .ok_or_else(|| Error("passive memory segments are not supported".into()))?;
-            let init_ty = expr_const_type(&offset, context.globals())?;
+            let init_ty = expr_const_type(offset, context.globals())?;
             if init_ty != ValueType::I32 {
                 return Err(Error("segment offset should return I32".into()));
             }
@@ -326,7 +326,7 @@ pub fn validate_module<V: Validator>(module: &Module) -> Result<V::Output, Error
                 .offset()
                 .as_ref()
                 .ok_or_else(|| Error("passive element segments are not supported".into()))?;
-            let init_ty = expr_const_type(&offset, context.globals())?;
+            let init_ty = expr_const_type(offset, context.globals())?;
             if init_ty != ValueType::I32 {
                 return Err(Error("segment offset should return I32".into()));
             }