Cleanup (#162)

* Remove unnecessary references

* Shorten expressions

* Remove unnecessary reference

* Simplify expression

* Fix formatting

src/gas/mod.rs

@@ -109,7 +109,7 @@ impl Counter {
 		self.finalize_metered_block(cursor)?;
 
 		// Pop the control block stack.
-		let closing_control_block = self.stack.pop().ok_or_else(|| ())?;
+		let closing_control_block = self.stack.pop().ok_or(())?;
 		let closing_control_index = self.stack.len();
 
 		if self.stack.is_empty() {
@@ -118,7 +118,7 @@ impl Counter {
 
 		// Update the lowest_forward_br_target for the control block now on top of the stack.
 		{
-			let control_block = self.stack.last_mut().ok_or_else(|| ())?;
+			let control_block = self.stack.last_mut().ok_or(())?;
 			control_block.lowest_forward_br_target = min(
 				control_block.lowest_forward_br_target,
 				closing_control_block.lowest_forward_br_target,
@@ -140,7 +140,7 @@ impl Counter {
 	/// Finalized blocks have final cost which will not change later.
 	fn finalize_metered_block(&mut self, cursor: usize) -> Result<(), ()> {
 		let closing_metered_block = {
-			let control_block = self.stack.last_mut().ok_or_else(|| ())?;
+			let control_block = self.stack.last_mut().ok_or(())?;
 			mem::replace(
 				&mut control_block.active_metered_block,
 				MeteredBlock { start_pos: cursor + 1, cost: 0 },
@@ -181,14 +181,14 @@ impl Counter {
 		// Update the lowest_forward_br_target of the current control block.
 		for &index in indices {
 			let target_is_loop = {
-				let target_block = self.stack.get(index).ok_or_else(|| ())?;
+				let target_block = self.stack.get(index).ok_or(())?;
 				target_block.is_loop
 			};
 			if target_is_loop {
 				continue
 			}
 
-			let control_block = self.stack.last_mut().ok_or_else(|| ())?;
+			let control_block = self.stack.last_mut().ok_or(())?;
 			control_block.lowest_forward_br_target =
 				min(control_block.lowest_forward_br_target, index);
 		}
@@ -203,14 +203,14 @@ impl Counter {
 
 	/// Get a reference to the currently active metered block.
 	fn active_metered_block(&mut self) -> Result<&mut MeteredBlock, ()> {
-		let top_block = self.stack.last_mut().ok_or_else(|| ())?;
+		let top_block = self.stack.last_mut().ok_or(())?;
 		Ok(&mut top_block.active_metered_block)
 	}
 
 	/// Increment the cost of the current block by the specified value.
 	fn increment(&mut self, val: u32) -> Result<(), ()> {
 		let top_block = self.active_metered_block()?;
-		top_block.cost = top_block.cost.checked_add(val).ok_or_else(|| ())?;
+		top_block.cost = top_block.cost.checked_add(val).ok_or(())?;
 		Ok(())
 	}
 }
@@ -308,20 +308,20 @@ pub(crate) fn determine_metered_blocks<R: Rules>(
 				counter.increment(instruction_cost)?;
 
 				// Label is a relative index into the control stack.
-				let active_index = counter.active_control_block_index().ok_or_else(|| ())?;
+				let active_index = counter.active_control_block_index().ok_or(())?;
-				let target_index = active_index.checked_sub(*label as usize).ok_or_else(|| ())?;
+				let target_index = active_index.checked_sub(*label as usize).ok_or(())?;
 				counter.branch(cursor, &[target_index])?;
 			},
 			BrTable(br_table_data) => {
 				counter.increment(instruction_cost)?;
 
-				let active_index = counter.active_control_block_index().ok_or_else(|| ())?;
+				let active_index = counter.active_control_block_index().ok_or(())?;
 				let target_indices = [br_table_data.default]
 					.iter()
 					.chain(br_table_data.table.iter())
 					.map(|label| active_index.checked_sub(*label as usize))
 					.collect::<Option<Vec<_>>>()
-					.ok_or_else(|| ())?;
+					.ok_or(())?;
 				counter.branch(cursor, &target_indices)?;
 			},
 			Return => {

src/graph.rs

@@ -723,7 +723,7 @@ fn custom_round(
 	idx: &mut usize,
 	sections: &mut Vec<elements::Section>,
 ) {
-	while let Some(other_section) = map.get(&idx) {
+	while let Some(other_section) = map.get(idx) {
 		sections.push(other_section.clone());
 		*idx += 1;
 	}

src/optimizer.rs

@@ -43,14 +43,14 @@ pub fn optimize(
 	}
 
 	// If there is start function in module, it should stary
-	module.start_section().map(|ss| stay.insert(resolve_function(&module, ss)));
+	module.start_section().map(|ss| stay.insert(resolve_function(module, ss)));
 
 	// All symbols used in data/element segments are also should be preserved
 	let mut init_symbols = Vec::new();
 	if let Some(data_section) = module.data_section() {
 		for segment in data_section.entries() {
 			push_code_symbols(
-				&module,
+				module,
 				segment
 					.offset()
 					.as_ref()
@@ -63,7 +63,7 @@ pub fn optimize(
 	if let Some(elements_section) = module.elements_section() {
 		for segment in elements_section.entries() {
 			push_code_symbols(
-				&module,
+				module,
 				segment
 					.offset()
 					.as_ref()
@@ -72,7 +72,7 @@ pub fn optimize(
 				&mut init_symbols,
 			);
 			for func_index in segment.members() {
-				stay.insert(resolve_function(&module, *func_index));
+				stay.insert(resolve_function(module, *func_index));
 			}
 		}
 	}
@@ -403,13 +403,9 @@ pub fn optimize(
 	}
 
 	// Also drop all custom sections
-	module.sections_mut().retain(|section| {
+	module
-		if let elements::Section::Custom(_) = section {
+		.sections_mut()
-			false
+		.retain(|section| !matches!(section, elements::Section::Custom(_)));
-		} else {
-			true
-		}
-	});
 
 	Ok(())
 }

src/pack.rs

@@ -120,7 +120,7 @@ pub fn pack_instance(
 			mbuilder.push_import(
 				builder::import()
 					.module("env")
-					.field(&target.symbols().ret)
+					.field(target.symbols().ret)
 					.external()
 					.func(import_sig)
 					.build(),
@@ -172,11 +172,10 @@ pub fn pack_instance(
 	let last_function_index = ctor_module.functions_space();
 
 	// We ensure here that module has the DataSection
-	if ctor_module
+	if !ctor_module
 		.sections()
 		.iter()
-		.find(|section| matches!(**section, Section::Data(_)))
+		.any(|section| matches!(*section, Section::Data(_)))
-		.is_none()
 	{
 		// DataSection has to be the last non-custom section according the to the spec
 		ctor_module

src/rules.rs

@@ -340,10 +340,6 @@ impl Rules for Set {
 	}
 
 	fn memory_grow_cost(&self) -> Option<MemoryGrowCost> {
-		if let Some(val) = NonZeroU32::new(self.grow) {
+		NonZeroU32::new(self.grow).map(MemoryGrowCost::Linear)
-			Some(MemoryGrowCost::Linear(val))
-		} else {
-			None
-		}
 	}
 }

src/stack_height/max_height.rs

@@ -80,10 +80,7 @@ impl Stack {
 	/// Returns `Err` if the control stack is empty.
 	fn pop_frame(&mut self) -> Result<Frame, Error> {
 		trace!(target: "max_height", "pop_frame: {:?}", self.control_stack.last());
-		Ok(self
+		self.control_stack.pop().ok_or_else(|| Error("stack must be non-empty".into()))
-			.control_stack
-			.pop()
-			.ok_or_else(|| Error("stack must be non-empty".into()))?)
 	}
 
 	/// Truncate the height of value stack to the specified height.

src/stack_height/mod.rs

@@ -176,7 +176,7 @@ fn compute_stack_costs(module: &elements::Module) -> Result<Vec<u32>, Error> {
 				// We can't calculate stack_cost of the import functions.
 				Ok(0)
 			} else {
-				compute_stack_cost(func_idx as u32, &module)
+				compute_stack_cost(func_idx as u32, module)
 			}
 		})
 		.collect()