Fix Default for enums with bool underlying type (#504)

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -4306,7 +4306,7 @@ std::string Converter::GetDefaultAsStringFallback(clang::QualType qual_type) {
   if (qual_type->isEnumeralType()) {
     auto enum_decl = qual_type->castAs<clang::EnumType>()->getDecl();
     if (enum_decl->enumerators().empty()) {
-      return std::string(1, token::kZero);
+      return GetDefaultAsString(enum_decl->getIntegerType());
     }
     return EnumeratorName(*enum_decl->enumerator_begin());
   }

tests/unit/enum_underlying_type.cpp

@@ -13,6 +13,12 @@ enum Sized : uint16_t { SIZED_A = 1, SIZED_B = 0xFFFF };
 
 enum class Scoped : int8_t { NEG = -2, POS = 2 };
 
+enum Empty : bool {};
+
+struct HoldsEmpty {
+  Empty e{};
+};
+
 int main() {
   Flag flag = FLAG_ON;
   assert(flag);
@@ -45,5 +51,10 @@ int main() {
   Scoped sc = Scoped::NEG;
   assert(static_cast<int>(sc) == -2);
   assert(static_cast<int8_t>(Scoped::POS) == 2);
+
+  HoldsEmpty he;
+  assert(!he.e);
+  Empty ev{};
+  assert(ev == he.e);
   return 0;
 }

tests/unit/out/refcount/enum_underlying_type.rs

@@ -24,6 +24,20 @@ pub const Sized_SIZED_B: Sized = 65535;
 pub type Scoped = i8;
 pub const Scoped_NEG: Scoped = -2;
 pub const Scoped_POS: Scoped = 2;
+pub type Empty = bool;
+#[derive(Clone, Record, ByteRepr, VaArg, FnPtrArg)]
+#[byte_size(1)]
+pub struct HoldsEmpty {
+    #[offset(0)]
+    pub e: Empty,
+}
+impl Default for HoldsEmpty {
+    fn default() -> Self {
+        HoldsEmpty {
+            e: <Empty>::default(),
+        }
+    }
+}
 pub fn main() {
     __cpp2rust_init_globals();
     std::process::exit(main_0());
@@ -55,6 +69,10 @@ fn main_0() -> i32 {
     let mut sc: Scoped = Scoped_NEG;
     assert!(((sc as i32) == -2_i32));
     assert!((((Scoped_POS as i8) as i32) == 2));
+    let mut he: HoldsEmpty = <HoldsEmpty>::default();
+    assert!(!(he.e));
+    let mut ev: Empty = <Empty>::default();
+    assert!(((ev as i32) == (he.e as i32)));
     return 0;
 }
 pub fn __cpp2rust_init_globals() {}

tests/unit/out/unsafe/enum_underlying_type.rs

@@ -24,6 +24,17 @@ pub const Sized_SIZED_B: Sized = 65535;
 pub type Scoped = i8;
 pub const Scoped_NEG: Scoped = -2;
 pub const Scoped_POS: Scoped = 2;
+pub type Empty = bool;
+#[repr(C)]
+#[derive(Copy, Clone, VaArg, FnPtrArg)]
+pub struct HoldsEmpty {
+    pub e: Empty,
+}
+impl Default for HoldsEmpty {
+    fn default() -> Self {
+        HoldsEmpty { e: false }
+    }
+}
 pub fn main() {
     unsafe {
         __cpp2rust_init_globals();
@@ -57,6 +68,10 @@ unsafe fn main_0() -> i32 {
     let mut sc: Scoped = Scoped_NEG;
     assert!(((sc as i32) == (-2_i32)));
     assert!((((Scoped_POS as i8) as i32) == (2)));
+    let mut he: HoldsEmpty = <HoldsEmpty>::default();
+    assert!(!(he.e));
+    let mut ev: Empty = false;
+    assert!(((ev as i32) == (he.e as i32)));
     return 0;
 }
 pub unsafe fn __cpp2rust_init_globals() {}