Merge branch 'main' of https://github.com/rust-lang/rust-bindgen into HEAD

Author: adetaylor

bindgen-tests/tests/expectations/tests/char16_t.rs

@@ -0,0 +1,4 @@
+// bindgen-flags: --use-distinct-char16-t --raw-line '#[repr(transparent)] pub struct bindgen_cchar16_t(u16);' -- -x c++ -std=c++14
+
+void receive_char16_t(char16_t input) {
+}

bindgen-tests/tests/headers/char16_t.hpp

@@ -140,7 +140,9 @@ fn compare_item_info(
             expected,
             generated,
         ),
-        DiscoveredItem::Enum { .. } => compare_enum_info(expected_item, generated_item),
+        DiscoveredItem::Enum { .. } => {
+            compare_enum_info(expected_item, generated_item)
+        }
         // DiscoveredItem::Mod { final_name } => todo!(),
         // DiscoveredItem::Function { final_name } => todo!(),
         // DiscoveredItem::Method { final_name, parent } => todo!(),
@@ -222,7 +224,6 @@ pub fn compare_union_info(
     }
 }
 
-
 pub fn compare_enum_info(
     expected_item: &DiscoveredItem,
     generated_item: &DiscoveredItem,

bindgen-tests/tests/parse_callbacks/item_discovery_callback/mod.rs

@@ -200,7 +200,12 @@ pub(crate) mod ast_ty {
         match ik {
             IntKind::Bool => syn::parse_quote! { bool },
             IntKind::Char { .. } => raw_type(ctx, "c_char"),
-            IntKind::Char16 => raw_type(ctx, "c_char16_t"),
+            // The following is used only when an unusual command-line
+            // argument is used. bindgen_cchar16_t is not a real type;
+            // but this allows downstream postprocessors to distinguish
+            // this case and do something special for C++ bindings
+            // containing char16_t.
+            IntKind::Char16 => syn::parse_quote! { bindgen_cchar16_t },
             IntKind::SChar => raw_type(ctx, "c_schar"),
             IntKind::UChar => raw_type(ctx, "c_uchar"),
             IntKind::Short => raw_type(ctx, "c_short"),

bindgen/codegen/helpers.rs

@@ -182,19 +182,6 @@ options! {
         as_args: "--represent-cxx-operators",
     },
 
-    /// Whether we should distinguish between 'char16_t' and 'u16'
-    use_distinct_char16_t: bool {
-        methods: {
-            /// If this is true, denote 'char16_t' as a separate type from 'u16'
-            /// Disabled by default.
-            pub fn use_distinct_char16_t(mut self, doit: bool) -> Builder {
-                self.options.use_distinct_char16_t = doit;
-                self
-            }
-        },
-        as_args: "--use-distinct-char16-t",
-    },
-
     /// Use a newtype wrapper to clearly denote "opaque" types; that is,
     /// types where bindgen has generated a type matching the size and
     /// alignment of the C++ type but without any knowledge of what's
@@ -267,6 +254,27 @@ options! {
         as_args: "--use-unused-template-param-newtype-wrapper",
     },
 
+    /// Whether we should distinguish between 'char16_t' and 'u16'.
+    /// As standard, bindgen represents `char16_t` as `u16`.
+    /// Rust does not have a `std::os::raw::c_char16_t` type, and thus
+    /// we can't use a built-in Rust type in the generated bindings.
+    /// But for some uses of bindgen, especially when downstream
+    /// post-processing occurs, it's important to distinguish `char16_t`
+    /// from normal `uint16_t`. When this option is enabled, bindgen
+    /// generates a fake type called `bindgen_cchar16_t`. Downstream
+    /// code post-processors should arrange to replace this with a
+    /// real type.
+    use_distinct_char16_t: bool {
+        methods: {
+            /// If this is true, denote 'char16_t' as a separate type from 'u16'
+            /// Disabled by default.
+            pub fn use_distinct_char16_t(mut self, doit: bool) -> Builder {
+                self.options.use_distinct_char16_t = doit;
+                self
+            }
+        },
+        as_args: "--use-distinct-char16-t",
+    },
 
     /// Types that have been blocklisted and should not appear anywhere in the generated code.
     blocklisted_types: RegexSet {