Use Options::DEFAULT to fill out Options constructor

Now-upstreamed changes require the `Options` structure to define more
fields. We use a `const` variable here (versus `impl Default`) so it can
be used in other `const` contexts.

Author: abrown

src/fuzzing/fastalloc.rs

@@ -11,6 +11,7 @@ const OPTIONS: func::Options = func::Options {
     clobbers: true,
     reftypes: false,
     callsite_ish_constraints: true,
+    ..func::Options::DEFAULT
 };
 
 /// A convenience wrapper to generate a [`func::Func`] with `fastalloc`-specific

src/fuzzing/func.rs

@@ -376,27 +376,26 @@ pub struct Options {
     pub num_clobbers_per_inst: RangeInclusive<usize>,
 }
 
-impl core::default::Default for Options {
-    fn default() -> Self {
-        Options {
-            reused_inputs: false,
-            fixed_regs: false,
-            fixed_nonallocatable: false,
-            clobbers: false,
-            reftypes: false,
-            callsite_ish_constraints: false,
-            num_blocks: 1..=100,
-            num_vregs_per_block: 5..=15,
-            num_uses_per_inst: 0..=10,
-            num_callsite_ish_vregs_per_inst: 0..=20,
-            num_clobbers_per_inst: 0..=10,
-        }
-    }
+impl Options {
+    /// Default options for generating functions.
+    pub const DEFAULT: Self = Self {
+        reused_inputs: false,
+        fixed_regs: false,
+        fixed_nonallocatable: false,
+        clobbers: false,
+        reftypes: false,
+        callsite_ish_constraints: false,
+        num_blocks: 1..=100,
+        num_vregs_per_block: 5..=15,
+        num_uses_per_inst: 0..=10,
+        num_callsite_ish_vregs_per_inst: 0..=20,
+        num_clobbers_per_inst: 0..=10,
+    };
 }
 
 impl Arbitrary<'_> for Func {
     fn arbitrary(u: &mut Unstructured) -> ArbitraryResult<Func> {
-        Func::arbitrary_with_options(u, &Options::default())
+        Func::arbitrary_with_options(u, &Options::DEFAULT)
     }
 }
 

src/fuzzing/ion.rs

@@ -13,6 +13,7 @@ const OPTIONS: func::Options = func::Options {
     clobbers: true,
     reftypes: true,
     callsite_ish_constraints: true,
+    ..func::Options::DEFAULT
 };
 
 /// A convenience wrapper to generate a [`func::Func`] with `ion`-specific
@@ -26,15 +27,7 @@ pub struct TestCase {
 
 impl Arbitrary<'_> for TestCase {
     fn arbitrary(u: &mut Unstructured) -> Result<TestCase> {
-        let options = func::Options {
-            reused_inputs: true,
-            fixed_regs: true,
-            fixed_nonallocatable: true,
-            clobbers: true,
-            reftypes: true,
-            callsite_ish_constraints: true,
-        };
-        let func = func::Func::arbitrary_with_options(u, &options)?;
+        let func = func::Func::arbitrary_with_options(u, &OPTIONS)?;
         let annotate = bool::arbitrary(u)?;
         let check_ssa = bool::arbitrary(u)?;
         Ok(TestCase {