Avoid collision between tag and typedef identifier (#166)

C allows name collision between the following 2 declarations:

```c
struct X {};
typedef enum {} X;
```

The 2 declarations live in different name spaces:

6.2.3 Name spaces of identifiers
[...] there are separate namespaces for various categories of
identifiers, as follows:
1. the tags of structures, unions, and enumerations (disambiguated by
following any) of the keywords struct, union, or enum);
2. all other identifiers, called ordinary identifiers (declared in
ordinary declarators or as enumeration constants).

`struct X {}` lives in namespace 1 and `typedef enum {} X` lives in
namespace 2.

We cannot translate both to `X` in the Rust code. We need to
disambiguate between the 2 names. I chose to translate them as:

```
struct X {} -> X
typedef enum {} X -> X_enum
```

C++ does not have the name space rule for identifiers. I added the
`tag->getASTContext().getLangOpts().CPlusPlus` check in
DisambiguateAnonymousTag to avoid polluting the C++ generated files.

---------

Co-authored-by: Nuno Lopes <nuno.lopes@tecnico.ulisboa.pt>

Author: lucic71

tests/unit/out/refcount/anonymous_enum_c.rs

@@ -7,37 +7,37 @@ use std::io::{Read, Seek, Write};
 use std::os::fd::AsFd;
 use std::rc::{Rc, Weak};
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_0 {
+enum anon_enum_3 {
     #[default]
     FIRST_A = 0,
     FIRST_B = 1,
 }
-impl From<i32> for anon_0 {
-    fn from(n: i32) -> anon_0 {
+impl From<i32> for anon_enum_3 {
+    fn from(n: i32) -> anon_enum_3 {
         match n {
-            0 => anon_0::FIRST_A,
-            1 => anon_0::FIRST_B,
-            _ => panic!("invalid anon_0 value: {}", n),
+            0 => anon_enum_3::FIRST_A,
+            1 => anon_enum_3::FIRST_B,
+            _ => panic!("invalid anon_enum_3 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_0);
+libcc2rs::impl_enum_inc_dec!(anon_enum_3);
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_1 {
+enum anon_enum_11 {
     #[default]
     SECOND_A = 0,
     SECOND_B = 1,
 }
-impl From<i32> for anon_1 {
-    fn from(n: i32) -> anon_1 {
+impl From<i32> for anon_enum_11 {
+    fn from(n: i32) -> anon_enum_11 {
         match n {
-            0 => anon_1::SECOND_A,
-            1 => anon_1::SECOND_B,
-            _ => panic!("invalid anon_1 value: {}", n),
+            0 => anon_enum_11::SECOND_A,
+            1 => anon_enum_11::SECOND_B,
+            _ => panic!("invalid anon_enum_11 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_1);
+libcc2rs::impl_enum_inc_dec!(anon_enum_11);
 #[derive(Default)]
 pub struct S {
     pub a: Value<i32>,
@@ -69,63 +69,65 @@ impl From<i32> for TdEnum_enum {
 }
 libcc2rs::impl_enum_inc_dec!(TdEnum_enum);
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_2 {
+enum anon_enum_24 {
     #[default]
     FIELD_A = 0,
     FIELD_B = 1,
 }
-impl From<i32> for anon_2 {
-    fn from(n: i32) -> anon_2 {
+impl From<i32> for anon_enum_24 {
+    fn from(n: i32) -> anon_enum_24 {
         match n {
-            0 => anon_2::FIELD_A,
-            1 => anon_2::FIELD_B,
-            _ => panic!("invalid anon_2 value: {}", n),
+            0 => anon_enum_24::FIELD_A,
+            1 => anon_enum_24::FIELD_B,
+            _ => panic!("invalid anon_enum_24 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_2);
+libcc2rs::impl_enum_inc_dec!(anon_enum_24);
 #[derive(Default)]
 pub struct WithAnonField {
     pub a: Value<i32>,
-    pub field: Value<anon_2>,
+    pub field: Value<anon_enum_24>,
 }
 impl ByteRepr for WithAnonField {}
 pub fn main() {
     std::process::exit(main_0());
 }
 fn main_0() -> i32 {
     #[derive(Clone, Copy, PartialEq, Debug, Default)]
-    enum anon_3 {
+    enum anon_enum_31 {
         #[default]
         THIRD_A = 0,
         THIRD_B = 1,
     }
-    impl From<i32> for anon_3 {
-        fn from(n: i32) -> anon_3 {
+    impl From<i32> for anon_enum_31 {
+        fn from(n: i32) -> anon_enum_31 {
             match n {
-                0 => anon_3::THIRD_A,
-                1 => anon_3::THIRD_B,
-                _ => panic!("invalid anon_3 value: {}", n),
+                0 => anon_enum_31::THIRD_A,
+                1 => anon_enum_31::THIRD_B,
+                _ => panic!("invalid anon_enum_31 value: {}", n),
             }
         }
     }
-    libcc2rs::impl_enum_inc_dec!(anon_3);
-    assert!(((((anon_0::FIRST_A as i32) != (anon_0::FIRST_B as i32)) as i32) != 0));
-    assert!(((((anon_1::SECOND_A as i32) != (anon_1::SECOND_B as i32)) as i32) != 0));
-    assert!(((((anon_3::THIRD_A as i32) != (anon_3::THIRD_B as i32)) as i32) != 0));
+    libcc2rs::impl_enum_inc_dec!(anon_enum_31);
+    assert!(((((anon_enum_3::FIRST_A as i32) != (anon_enum_3::FIRST_B as i32)) as i32) != 0));
+    assert!(((((anon_enum_11::SECOND_A as i32) != (anon_enum_11::SECOND_B as i32)) as i32) != 0));
+    assert!(((((anon_enum_31::THIRD_A as i32) != (anon_enum_31::THIRD_B as i32)) as i32) != 0));
     let td: Value<TdEnum_enum> = Rc::new(RefCell::new(TdEnum_enum::TD_A));
     assert!((((((*td.borrow()) as u32) == ((TdEnum_enum::TD_A as i32) as u32)) as i32) != 0));
     (*td.borrow_mut()) = TdEnum_enum::TD_B;
     assert!((((((*td.borrow()) as u32) == ((TdEnum_enum::TD_B as i32) as u32)) as i32) != 0));
     let w: Value<WithAnonField> = <Value<WithAnonField>>::default();
-    (*(*w.borrow()).field.borrow_mut()) = anon_2::FIELD_A;
+    (*(*w.borrow()).field.borrow_mut()) = anon_enum_24::FIELD_A;
     assert!(
-        (((((*(*w.borrow()).field.borrow()) as u32) == ((anon_2::FIELD_A as i32) as u32)) as i32)
+        (((((*(*w.borrow()).field.borrow()) as u32) == ((anon_enum_24::FIELD_A as i32) as u32))
+            as i32)
             != 0)
     );
-    (*(*w.borrow()).field.borrow_mut()) = anon_2::FIELD_B;
+    (*(*w.borrow()).field.borrow_mut()) = anon_enum_24::FIELD_B;
     assert!(
-        (((((*(*w.borrow()).field.borrow()) as u32) == ((anon_2::FIELD_B as i32) as u32)) as i32)
+        (((((*(*w.borrow()).field.borrow()) as u32) == ((anon_enum_24::FIELD_B as i32) as u32))
+            as i32)
             != 0)
     );
     return 0;

tests/unit/out/refcount/enum_int_interop_c.rs

@@ -81,17 +81,17 @@ thread_local!(
 thread_local!(
     pub static entries_3: Value<Box<[Entry]>> = Rc::new(RefCell::new(Box::new([
         Entry {
-            name: Rc::new(RefCell::new(Ptr::from_string_literal(b"first"))),
+            name: Rc::new(RefCell::new(Ptr::from_string_literal("first"))),
             color: Rc::new(RefCell::new(Color::RED)),
             opt: Rc::new(RefCell::new(Option::OPT_NONE)),
         },
         Entry {
-            name: Rc::new(RefCell::new(Ptr::from_string_literal(b"second"))),
+            name: Rc::new(RefCell::new(Ptr::from_string_literal("second"))),
             color: Rc::new(RefCell::new(Color::GREEN)),
             opt: Rc::new(RefCell::new(Option::OPT_A)),
         },
         Entry {
-            name: Rc::new(RefCell::new(Ptr::from_string_literal(b"third"))),
+            name: Rc::new(RefCell::new(Ptr::from_string_literal("third"))),
             color: Rc::new(RefCell::new(Color::BLUE)),
             opt: Rc::new(RefCell::new(Option::OPT_C)),
         },
@@ -106,16 +106,16 @@ pub fn classify_option_5(option: i32) -> i32 {
     'switch: {
         let __match_cond = (*option.borrow());
         match __match_cond {
-            __v if __v == (Option::OPT_NONE as i32) => {
+            v if v == (Option::OPT_NONE as i32) => {
                 return -1_i32;
             }
-            __v if __v == (Option::OPT_A as i32) => {
+            v if v == (Option::OPT_A as i32) => {
                 return 1;
             }
-            __v if __v == (Option::OPT_B as i32) => {
+            v if v == (Option::OPT_B as i32) => {
                 return 2;
             }
-            __v if __v == (Option::OPT_C as i32) => {
+            v if v == (Option::OPT_C as i32) => {
                 return 3;
             }
             _ => {
@@ -143,13 +143,13 @@ fn main_0() -> i32 {
     'switch: {
         let __match_cond = ((*c.borrow()) as u32);
         match __match_cond {
-            __v if __v == (0 as u32) => {
+            v if v == (0 as u32) => {
                 break 'switch;
             }
-            __v if __v == (1 as u32) => {
+            v if v == (1 as u32) => {
                 return 1;
             }
-            __v if __v == (2 as u32) => {
+            v if v == (2 as u32) => {
                 return 2;
             }
             _ => {
@@ -209,13 +209,13 @@ fn main_0() -> i32 {
     'switch: {
         let __match_cond = ((*t.borrow()) as u32);
         match __match_cond {
-            __v if __v == ((Tag_enum::TAG_ZERO as i32) as u32) => {
+            v if v == ((Tag_enum::TAG_ZERO as i32) as u32) => {
                 return 90;
             }
-            __v if __v == (1 as u32) => {
+            v if v == (1 as u32) => {
                 return 91;
             }
-            __v if __v == (2 as u32) => {
+            v if v == (2 as u32) => {
                 break 'switch;
             }
             _ => {}

tests/unit/out/unsafe/anonymous_enum_c.rs

@@ -7,37 +7,37 @@ use std::io::{Read, Seek, Write};
 use std::os::fd::{AsFd, FromRawFd, IntoRawFd};
 use std::rc::Rc;
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_0 {
+enum anon_enum_3 {
     #[default]
     FIRST_A = 0,
     FIRST_B = 1,
 }
-impl From<i32> for anon_0 {
-    fn from(n: i32) -> anon_0 {
+impl From<i32> for anon_enum_3 {
+    fn from(n: i32) -> anon_enum_3 {
         match n {
-            0 => anon_0::FIRST_A,
-            1 => anon_0::FIRST_B,
-            _ => panic!("invalid anon_0 value: {}", n),
+            0 => anon_enum_3::FIRST_A,
+            1 => anon_enum_3::FIRST_B,
+            _ => panic!("invalid anon_enum_3 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_0);
+libcc2rs::impl_enum_inc_dec!(anon_enum_3);
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_1 {
+enum anon_enum_11 {
     #[default]
     SECOND_A = 0,
     SECOND_B = 1,
 }
-impl From<i32> for anon_1 {
-    fn from(n: i32) -> anon_1 {
+impl From<i32> for anon_enum_11 {
+    fn from(n: i32) -> anon_enum_11 {
         match n {
-            0 => anon_1::SECOND_A,
-            1 => anon_1::SECOND_B,
-            _ => panic!("invalid anon_1 value: {}", n),
+            0 => anon_enum_11::SECOND_A,
+            1 => anon_enum_11::SECOND_B,
+            _ => panic!("invalid anon_enum_11 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_1);
+libcc2rs::impl_enum_inc_dec!(anon_enum_11);
 #[repr(C)]
 #[derive(Copy, Clone, Default)]
 pub struct S {
@@ -60,26 +60,26 @@ impl From<i32> for TdEnum_enum {
 }
 libcc2rs::impl_enum_inc_dec!(TdEnum_enum);
 #[derive(Clone, Copy, PartialEq, Debug, Default)]
-enum anon_2 {
+enum anon_enum_24 {
     #[default]
     FIELD_A = 0,
     FIELD_B = 1,
 }
-impl From<i32> for anon_2 {
-    fn from(n: i32) -> anon_2 {
+impl From<i32> for anon_enum_24 {
+    fn from(n: i32) -> anon_enum_24 {
         match n {
-            0 => anon_2::FIELD_A,
-            1 => anon_2::FIELD_B,
-            _ => panic!("invalid anon_2 value: {}", n),
+            0 => anon_enum_24::FIELD_A,
+            1 => anon_enum_24::FIELD_B,
+            _ => panic!("invalid anon_enum_24 value: {}", n),
         }
     }
 }
-libcc2rs::impl_enum_inc_dec!(anon_2);
+libcc2rs::impl_enum_inc_dec!(anon_enum_24);
 #[repr(C)]
 #[derive(Copy, Clone, Default)]
 pub struct WithAnonField {
     pub a: i32,
-    pub field: anon_2,
+    pub field: anon_enum_24,
 }
 pub fn main() {
     unsafe {
@@ -88,32 +88,32 @@ pub fn main() {
 }
 unsafe fn main_0() -> i32 {
     #[derive(Clone, Copy, PartialEq, Debug, Default)]
-    enum anon_3 {
+    enum anon_enum_31 {
         #[default]
         THIRD_A = 0,
         THIRD_B = 1,
     }
-    impl From<i32> for anon_3 {
-        fn from(n: i32) -> anon_3 {
+    impl From<i32> for anon_enum_31 {
+        fn from(n: i32) -> anon_enum_31 {
             match n {
-                0 => anon_3::THIRD_A,
-                1 => anon_3::THIRD_B,
-                _ => panic!("invalid anon_3 value: {}", n),
+                0 => anon_enum_31::THIRD_A,
+                1 => anon_enum_31::THIRD_B,
+                _ => panic!("invalid anon_enum_31 value: {}", n),
             }
         }
     }
-    libcc2rs::impl_enum_inc_dec!(anon_3);
-    assert!(((((anon_0::FIRST_A as i32) != (anon_0::FIRST_B as i32)) as i32) != 0));
-    assert!(((((anon_1::SECOND_A as i32) != (anon_1::SECOND_B as i32)) as i32) != 0));
-    assert!(((((anon_3::THIRD_A as i32) != (anon_3::THIRD_B as i32)) as i32) != 0));
+    libcc2rs::impl_enum_inc_dec!(anon_enum_31);
+    assert!(((((anon_enum_3::FIRST_A as i32) != (anon_enum_3::FIRST_B as i32)) as i32) != 0));
+    assert!(((((anon_enum_11::SECOND_A as i32) != (anon_enum_11::SECOND_B as i32)) as i32) != 0));
+    assert!(((((anon_enum_31::THIRD_A as i32) != (anon_enum_31::THIRD_B as i32)) as i32) != 0));
     let mut td: TdEnum_enum = TdEnum_enum::TD_A;
     assert!(((((td as u32) == ((TdEnum_enum::TD_A as i32) as u32)) as i32) != 0));
     td = (TdEnum_enum::TD_B).clone();
     assert!(((((td as u32) == ((TdEnum_enum::TD_B as i32) as u32)) as i32) != 0));
     let mut w: WithAnonField = <WithAnonField>::default();
-    w.field = anon_2::FIELD_A;
-    assert!(((((w.field as u32) == ((anon_2::FIELD_A as i32) as u32)) as i32) != 0));
-    w.field = (anon_2::FIELD_B).clone();
-    assert!(((((w.field as u32) == ((anon_2::FIELD_B as i32) as u32)) as i32) != 0));
+    w.field = anon_enum_24::FIELD_A;
+    assert!(((((w.field as u32) == ((anon_enum_24::FIELD_A as i32) as u32)) as i32) != 0));
+    w.field = (anon_enum_24::FIELD_B).clone();
+    assert!(((((w.field as u32) == ((anon_enum_24::FIELD_B as i32) as u32)) as i32) != 0));
     return 0;
 }