feat: support enums, distinct types, unions and matching

source/diagnostics/diagnostics.hon

@@ -76,6 +76,19 @@ Code :: enum {
     namespace_not_value
     not_namespace
     invalid_import_alias
+    invalid_enum_backing
+    invalid_enum_value
+    enum_context_required
+    invalid_distinct_backing
+    invalid_union_tag
+    union_initializer_count
+    invalid_match_subject
+    invalid_match_pattern
+    duplicate_match_pattern
+    non_exhaustive_match
+    unreachable_match_arm
+    invalid_match_capture
+    inactive_union_field
 }
 
 Diagnostic :: struct {
@@ -173,5 +186,18 @@ messages :: $enummap.init(Code, []u8, {
     namespace_not_value = "package namespace cannot be used as a value",
     not_namespace = "member selection requires a package namespace",
     invalid_import_alias = "import requires an explicit valid identifier alias",
+    invalid_enum_backing = "enum backing must be a concrete integer type",
+    invalid_enum_value = "enum values require explicit backing and increasing representable constant integers",
+    enum_context_required = "enum literal requires an enum or tagged union context",
+    invalid_distinct_backing = "distinct requires a concrete runtime backing type",
+    invalid_union_tag = "union tag must be an enum containing every union variant",
+    union_initializer_count = "union construction requires exactly one member",
+    invalid_match_subject = "match subject must be an enum, tagged union, or scalar",
+    invalid_match_pattern = "invalid match pattern",
+    duplicate_match_pattern = "duplicate or overlapping match pattern",
+    non_exhaustive_match = "match is not exhaustive",
+    unreachable_match_arm = "match arm is unreachable",
+    invalid_match_capture = "payload capture requires compatible nonvoid tagged union variants",
+    inactive_union_field = "tagged union field is not active",
 })