Use Default trait for Position and DisplayFunctionAnnotations (#843)

cranelift/codegen/src/ir/function.rs

@@ -222,6 +222,7 @@ impl Function {
 }
 
 /// Additional annotations for function display.
+#[derive(Default)]
 pub struct DisplayFunctionAnnotations<'a> {
     /// Enable ISA annotations.
     pub isa: Option<&'a dyn TargetIsa>,
@@ -230,16 +231,6 @@ pub struct DisplayFunctionAnnotations<'a> {
     pub value_ranges: Option<&'a ValueLabelsRanges>,
 }
 
-impl<'a> DisplayFunctionAnnotations<'a> {
-    /// Create a DisplayFunctionAnnotations with all fields set to None.
-    pub fn default() -> Self {
-        DisplayFunctionAnnotations {
-            isa: None,
-            value_ranges: None,
-        }
-    }
-}
-
 impl<'a> From<Option<&'a dyn TargetIsa>> for DisplayFunctionAnnotations<'a> {
     fn from(isa: Option<&'a dyn TargetIsa>) -> DisplayFunctionAnnotations {
         DisplayFunctionAnnotations {

cranelift/frontend/src/frontend.rs

@@ -46,6 +46,7 @@ struct EbbData {
     user_param_count: usize,
 }
 
+#[derive(Default)]
 struct Position {
     ebb: PackedOption<Ebb>,
     basic_block: PackedOption<Block>,
@@ -59,13 +60,6 @@ impl Position {
         }
     }
 
-    fn default() -> Self {
-        Self {
-            ebb: PackedOption::default(),
-            basic_block: PackedOption::default(),
-        }
-    }
-
     fn is_default(&self) -> bool {
         self.ebb.is_none() && self.basic_block.is_none()
     }