Fix a non-C-like-enumeration size mismatch between Rust and C when using Style::Tag.

src/bindgen/ir/enumeration.rs

@@ -682,7 +682,8 @@ impl Source for Enum {
                 out.open_brace();
             }
 
-            if config.language == Language::C && !config.style.generate_typedef() {
+            if config.language == Language::C && !size.is_some() && !config.style.generate_typedef()
+            {
                 out.write("enum ");
             }
 

tests/expectations/both/enum.c

@@ -157,6 +157,30 @@ typedef struct I {
   };
 } I;
 
+enum P_Tag {
+  P0,
+  P1,
+};
+typedef uint8_t P_Tag;
+
+typedef struct P0_Body {
+  uint8_t _0;
+} P0_Body;
+
+typedef struct P1_Body {
+  uint8_t _0;
+  uint8_t _1;
+  uint8_t _2;
+} P1_Body;
+
+typedef struct P {
+  P_Tag tag;
+  union {
+    P0_Body p0;
+    P1_Body p1;
+  };
+} P;
+
 void root(Opaque *opaque,
           A a,
           B b,
@@ -172,4 +196,12 @@ void root(Opaque *opaque,
           L l,
           M m,
           N n,
-          O o);
+          O o,
+          P p);
+
+#include <stddef.h>
+#include "testing-helpers.h"
+static_assert(offsetof(CBINDGEN_STRUCT(P), tag) == 0, "unexpected offset for tag");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p0");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p1");
+static_assert(sizeof(CBINDGEN_STRUCT(P)) == 4, "unexpected size for P");

tests/expectations/both/enum.compat.c

@@ -217,6 +217,36 @@ typedef struct I {
   };
 } I;
 
+enum P_Tag
+#ifdef __cplusplus
+  : uint8_t
+#endif // __cplusplus
+ {
+  P0,
+  P1,
+};
+#ifndef __cplusplus
+typedef uint8_t P_Tag;
+#endif // __cplusplus
+
+typedef struct P0_Body {
+  uint8_t _0;
+} P0_Body;
+
+typedef struct P1_Body {
+  uint8_t _0;
+  uint8_t _1;
+  uint8_t _2;
+} P1_Body;
+
+typedef struct P {
+  P_Tag tag;
+  union {
+    P0_Body p0;
+    P1_Body p1;
+  };
+} P;
+
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
@@ -236,8 +266,16 @@ void root(Opaque *opaque,
           L l,
           M m,
           N n,
-          O o);
+          O o,
+          P p);
 
 #ifdef __cplusplus
 } // extern "C"
 #endif // __cplusplus
+
+#include <stddef.h>
+#include "testing-helpers.h"
+static_assert(offsetof(CBINDGEN_STRUCT(P), tag) == 0, "unexpected offset for tag");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p0");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p1");
+static_assert(sizeof(CBINDGEN_STRUCT(P)) == 4, "unexpected size for P");

tests/expectations/enum.c

@@ -157,6 +157,30 @@ typedef struct {
   };
 } I;
 
+enum P_Tag {
+  P0,
+  P1,
+};
+typedef uint8_t P_Tag;
+
+typedef struct {
+  uint8_t _0;
+} P0_Body;
+
+typedef struct {
+  uint8_t _0;
+  uint8_t _1;
+  uint8_t _2;
+} P1_Body;
+
+typedef struct {
+  P_Tag tag;
+  union {
+    P0_Body p0;
+    P1_Body p1;
+  };
+} P;
+
 void root(Opaque *opaque,
           A a,
           B b,
@@ -172,4 +196,12 @@ void root(Opaque *opaque,
           L l,
           M m,
           N n,
-          O o);
+          O o,
+          P p);
+
+#include <stddef.h>
+#include "testing-helpers.h"
+static_assert(offsetof(CBINDGEN_STRUCT(P), tag) == 0, "unexpected offset for tag");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p0");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p1");
+static_assert(sizeof(CBINDGEN_STRUCT(P)) == 4, "unexpected size for P");

tests/expectations/enum.compat.c

@@ -217,6 +217,36 @@ typedef struct {
   };
 } I;
 
+enum P_Tag
+#ifdef __cplusplus
+  : uint8_t
+#endif // __cplusplus
+ {
+  P0,
+  P1,
+};
+#ifndef __cplusplus
+typedef uint8_t P_Tag;
+#endif // __cplusplus
+
+typedef struct {
+  uint8_t _0;
+} P0_Body;
+
+typedef struct {
+  uint8_t _0;
+  uint8_t _1;
+  uint8_t _2;
+} P1_Body;
+
+typedef struct {
+  P_Tag tag;
+  union {
+    P0_Body p0;
+    P1_Body p1;
+  };
+} P;
+
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
@@ -236,8 +266,16 @@ void root(Opaque *opaque,
           L l,
           M m,
           N n,
-          O o);
+          O o,
+          P p);
 
 #ifdef __cplusplus
 } // extern "C"
 #endif // __cplusplus
+
+#include <stddef.h>
+#include "testing-helpers.h"
+static_assert(offsetof(CBINDGEN_STRUCT(P), tag) == 0, "unexpected offset for tag");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p0");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p1");
+static_assert(sizeof(CBINDGEN_STRUCT(P)) == 4, "unexpected size for P");

tests/expectations/enum.cpp

@@ -149,6 +149,29 @@ struct I {
   };
 };
 
+struct P {
+  enum class Tag : uint8_t {
+    P0,
+    P1,
+  };
+
+  struct P0_Body {
+    uint8_t _0;
+  };
+
+  struct P1_Body {
+    uint8_t _0;
+    uint8_t _1;
+    uint8_t _2;
+  };
+
+  Tag tag;
+  union {
+    P0_Body p0;
+    P1_Body p1;
+  };
+};
+
 extern "C" {
 
 void root(Opaque *opaque,
@@ -166,6 +189,14 @@ void root(Opaque *opaque,
           L l,
           M m,
           N n,
-          O o);
+          O o,
+          P p);
 
 } // extern "C"
+
+#include <stddef.h>
+#include "testing-helpers.h"
+static_assert(offsetof(CBINDGEN_STRUCT(P), tag) == 0, "unexpected offset for tag");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p0");
+static_assert(offsetof(CBINDGEN_STRUCT(P), p0) == 1, "unexpected offset for p1");
+static_assert(sizeof(CBINDGEN_STRUCT(P)) == 4, "unexpected size for P");

tests/expectations/tag/annotation.c

@@ -37,7 +37,7 @@ struct Bar_Body {
 };
 
 union F {
-  enum F_Tag tag;
+  F_Tag tag;
   struct Foo_Body foo;
   struct Bar_Body bar;
 };
@@ -59,7 +59,7 @@ struct There_Body {
 };
 
 struct H {
-  enum H_Tag tag;
+  H_Tag tag;
   union {
     struct Hello_Body hello;
     struct There_Body there;

tests/expectations/tag/annotation.compat.c

@@ -49,7 +49,7 @@ struct Bar_Body {
 };
 
 union F {
-  enum F_Tag tag;
+  F_Tag tag;
   struct Foo_Body foo;
   struct Bar_Body bar;
 };
@@ -77,7 +77,7 @@ struct There_Body {
 };
 
 struct H {
-  enum H_Tag tag;
+  H_Tag tag;
   union {
     struct Hello_Body hello;
     struct There_Body there;

tests/expectations/tag/asserted-cast.c

@@ -25,7 +25,7 @@ struct H_Bar_Body {
 };
 
 struct H {
-  enum H_Tag tag;
+  H_Tag tag;
   union {
     struct H_Foo_Body foo;
     struct H_Bar_Body bar;
@@ -49,7 +49,7 @@ struct J_Bar_Body {
 };
 
 struct J {
-  enum J_Tag tag;
+  J_Tag tag;
   union {
     struct J_Foo_Body foo;
     struct J_Bar_Body bar;
@@ -75,7 +75,7 @@ struct K_Bar_Body {
 };
 
 union K {
-  enum K_Tag tag;
+  K_Tag tag;
   struct K_Foo_Body foo;
   struct K_Bar_Body bar;
 };

tests/expectations/tag/asserted-cast.compat.c

@@ -31,7 +31,7 @@ struct H_Bar_Body {
 };
 
 struct H {
-  enum H_Tag tag;
+  H_Tag tag;
   union {
     struct H_Foo_Body foo;
     struct H_Bar_Body bar;
@@ -61,7 +61,7 @@ struct J_Bar_Body {
 };
 
 struct J {
-  enum J_Tag tag;
+  J_Tag tag;
   union {
     struct J_Foo_Body foo;
     struct J_Bar_Body bar;
@@ -93,7 +93,7 @@ struct K_Bar_Body {
 };
 
 union K {
-  enum K_Tag tag;
+  K_Tag tag;
   struct K_Foo_Body foo;
   struct K_Bar_Body bar;
 };

tests/expectations/tag/derive-eq.c

@@ -34,7 +34,7 @@ struct FooParen_Body {
 };
 
 union Bar {
-  enum Bar_Tag tag;
+  Bar_Tag tag;
   struct Bazz_Body bazz;
   struct FooNamed_Body foo_named;
   struct FooParen_Body foo_paren;

tests/expectations/tag/derive-eq.compat.c

@@ -40,7 +40,7 @@ struct FooParen_Body {
 };
 
 union Bar {
-  enum Bar_Tag tag;
+  Bar_Tag tag;
   struct Bazz_Body bazz;
   struct FooNamed_Body foo_named;
   struct FooParen_Body foo_paren;

tests/expectations/tag/destructor-and-copy-ctor.c

@@ -65,7 +65,7 @@ struct Slice4_Body_u32 {
 };
 
 struct Foo_u32 {
-  enum Foo_u32_Tag tag;
+  Foo_u32_Tag tag;
   union {
     struct Polygon1_Body_u32 polygon1;
     struct Slice1_Body_u32 slice1;
@@ -118,7 +118,7 @@ struct Slice24_Body_i32 {
 };
 
 union Baz_i32 {
-  enum Baz_i32_Tag tag;
+  Baz_i32_Tag tag;
   struct Polygon21_Body_i32 polygon21;
   struct Slice21_Body_i32 slice21;
   struct Slice22_Body_i32 slice22;
@@ -144,7 +144,7 @@ struct Taz3_Body {
 };
 
 union Taz {
-  enum Taz_Tag tag;
+  Taz_Tag tag;
   struct Taz1_Body taz1;
   struct Taz3_Body taz3;
 };
@@ -161,7 +161,7 @@ struct Taz2_Body {
 };
 
 union Tazz {
-  enum Tazz_Tag tag;
+  Tazz_Tag tag;
   struct Taz2_Body taz2;
 };