codegen: Avoid crashing on variadic unions without layout information.

bindgen-tests/tests/headers/variadic-union.hpp

@@ -0,0 +1,3 @@
+template <typename... _Types> union _Variadic_union {
+  _Variadic_union() = default;
+};

bindgen/clang.rs

@@ -945,7 +945,7 @@ impl Cursor {
     }
 
     /// Gets the tokens that correspond to that cursor.
-    pub(crate) fn tokens(&self) -> RawTokens {
+    pub(crate) fn tokens(&self) -> RawTokens<'_> {
         RawTokens::new(self)
     }
 
@@ -1006,7 +1006,7 @@ impl<'a> RawTokens<'a> {
     }
 
     /// Get an iterator over these tokens.
-    pub(crate) fn iter(&self) -> ClangTokenIterator {
+    pub(crate) fn iter(&self) -> ClangTokenIterator<'_> {
         ClangTokenIterator {
             tu: self.tu,
             raw: self.as_slice().iter(),

bindgen/codegen/mod.rs

@@ -2337,18 +2337,17 @@ impl CodeGenerator for CompInfo {
                 }
             }
         } else if is_union && !forward_decl {
-            // TODO(emilio): It'd be nice to unify this with the struct path
-            // above somehow.
-            let layout = layout.expect("Unable to get layout information?");
-            if struct_layout.requires_explicit_align(layout) {
-                explicit_align = Some(layout.align);
-            }
-
-            if !struct_layout.is_rust_union() {
-                let ty = helpers::blob(ctx, layout, false);
-                fields.push(quote! {
-                    pub bindgen_union_field: #ty ,
-                });
+            if let Some(layout) = layout {
+                // TODO(emilio): It'd be nice to unify this with the struct path above somehow.
+                if struct_layout.requires_explicit_align(layout) {
+                    explicit_align = Some(layout.align);
+                }
+                if !struct_layout.is_rust_union() {
+                    let ty = helpers::blob(ctx, layout, false);
+                    fields.push(quote! {
+                        pub bindgen_union_field: #ty ,
+                    });
+                }
             }
         }
 

bindgen/ir/context.rs

@@ -1228,7 +1228,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
 
     fn assert_no_dangling_item_traversal(
         &self,
-    ) -> traversal::AssertNoDanglingItemsTraversal {
+    ) -> traversal::AssertNoDanglingItemsTraversal<'_> {
         assert!(self.in_codegen_phase());
         assert_eq!(self.current_module, self.root_module);
 

bindgen/ir/ty.rs

@@ -243,7 +243,7 @@ impl Type {
     }
 
     /// Takes `name`, and returns a suitable identifier representation for it.
-    fn sanitize_name(name: &str) -> Cow<str> {
+    fn sanitize_name(name: &str) -> Cow<'_, str> {
         if clang::is_valid_identifier(name) {
             return Cow::Borrowed(name);
         }

bindgen/lib.rs

@@ -980,7 +980,7 @@ impl Bindings {
     }
 
     /// Gets the rustfmt path to rustfmt the generated bindings.
-    fn rustfmt_path(&self) -> io::Result<Cow<PathBuf>> {
+    fn rustfmt_path(&self) -> io::Result<Cow<'_, PathBuf>> {
         debug_assert!(matches!(self.options.formatter, Formatter::Rustfmt));
         if let Some(ref p) = self.options.rustfmt_path {
             return Ok(Cow::Borrowed(p));