Allow zero-sized fields in extern structs (#16404)

This change allows the following types to appear in extern structs:
* Zero-bit integers
* void
* zero-sized structs and packed structs
* enums with zero-bit backing integers
* arrays of any length with zero-size elements

6 files changed, 6 insertions, 6 deletions

diff --git a/test/cases/compile_errors/exported_enum_without_explicit_integer_tag_type.zig b/test/cases/compile_errors/exported_enum_without_explicit_integer_tag_type.zig
index 98a98f7e13..534f674fb2 100644
--- a/test/cases/compile_errors/exported_enum_without_explicit_integer_tag_type.zig
+++ b/test/cases/compile_errors/exported_enum_without_explicit_integer_tag_type.zig
@@ -14,5 +14,5 @@ comptime {
 // :3:5: error: unable to export type 'type'
 // :7:5: error: unable to export type 'tmp.E'
 // :7:5: note: enum tag type 'u1' is not extern compatible
-// :7:5: note: only integers with 8, 16, 32, 64 and 128 bits are extern compatible
+// :7:5: note: only integers with 0, 8, 16, 32, 64 and 128 bits are extern compatible
 // :1:11: note: enum declared here
diff --git a/test/cases/compile_errors/extern_struct_with_extern-compatible_but_inferred_integer_tag_type.zig b/test/cases/compile_errors/extern_struct_with_extern-compatible_but_inferred_integer_tag_type.zig
index 2faa7c8713..beee31721c 100644
--- a/test/cases/compile_errors/extern_struct_with_extern-compatible_but_inferred_integer_tag_type.zig
+++ b/test/cases/compile_errors/extern_struct_with_extern-compatible_but_inferred_integer_tag_type.zig
@@ -43,5 +43,5 @@ export fn entry() void {
 //
 // :33:8: error: extern structs cannot contain fields of type 'tmp.E'
 // :33:8: note: enum tag type 'u9' is not extern compatible
-// :33:8: note: only integers with power of two bits are extern compatible
+// :33:8: note: only integers with 0 or power of two bits are extern compatible
 // :2:15: note: enum declared here
diff --git a/test/cases/compile_errors/extern_struct_with_non-extern-compatible_integer_tag_type.zig b/test/cases/compile_errors/extern_struct_with_non-extern-compatible_integer_tag_type.zig
index a83edb6289..fd418566bc 100644
--- a/test/cases/compile_errors/extern_struct_with_non-extern-compatible_integer_tag_type.zig
+++ b/test/cases/compile_errors/extern_struct_with_non-extern-compatible_integer_tag_type.zig
@@ -13,5 +13,5 @@ export fn entry() void {
 //
 // :3:8: error: extern structs cannot contain fields of type 'tmp.E'
 // :3:8: note: enum tag type 'u31' is not extern compatible
-// :3:8: note: only integers with power of two bits are extern compatible
+// :3:8: note: only integers with 0 or power of two bits are extern compatible
 // :1:15: note: enum declared here
diff --git a/test/cases/compile_errors/extern_variable_has_non_extern_type.zig b/test/cases/compile_errors/extern_variable_has_non_extern_type.zig
index a572e77c28..ab460934e0 100644
--- a/test/cases/compile_errors/extern_variable_has_non_extern_type.zig
+++ b/test/cases/compile_errors/extern_variable_has_non_extern_type.zig
@@ -8,4 +8,4 @@ pub export fn entry() void {
 // target=native
 //
 // :1:17: error: extern variable cannot have type 'u3'
-// :1:17: note: only integers with power of two bits are extern compatible
+// :1:17: note: only integers with 0 or power of two bits are extern compatible
diff --git a/test/cases/compile_errors/function_with_non-extern_non-packed_enum_parameter.zig b/test/cases/compile_errors/function_with_non-extern_non-packed_enum_parameter.zig
index ae347470f2..ab257ead71 100644
--- a/test/cases/compile_errors/function_with_non-extern_non-packed_enum_parameter.zig
+++ b/test/cases/compile_errors/function_with_non-extern_non-packed_enum_parameter.zig
@@ -9,5 +9,5 @@ export fn entry(foo: Foo) void {
 //
 // :2:17: error: parameter of type 'tmp.Foo' not allowed in function with calling convention 'C'
 // :2:17: note: enum tag type 'u2' is not extern compatible
-// :2:17: note: only integers with 8, 16, 32, 64 and 128 bits are extern compatible
+// :2:17: note: only integers with 0, 8, 16, 32, 64 and 128 bits are extern compatible
 // :1:13: note: enum declared here
diff --git a/test/cases/compile_errors/variadic_arg_validation.zig b/test/cases/compile_errors/variadic_arg_validation.zig
index bddcef92f6..2e47a4fc1e 100644
--- a/test/cases/compile_errors/variadic_arg_validation.zig
+++ b/test/cases/compile_errors/variadic_arg_validation.zig
@@ -24,6 +24,6 @@ pub export fn entry3() void {
 // :4:33: error: integer and float literals passed to variadic function must be casted to a fixed-size number type
 // :9:24: error: arrays must be passed by reference to variadic function
 // :13:24: error: cannot pass 'u48' to variadic function
-// :13:24: note: only integers with power of two bits are extern compatible
+// :13:24: note: only integers with 0 or power of two bits are extern compatible
 // :17:24: error: cannot pass 'void' to variadic function
 // :17:24: note: 'void' is a zero bit type; for C 'void' use 'anyopaque'