Fix: Compiler assert when attempting to define multiple faults in a generic module. #2706

src/compiler/ast.c

@@ -327,6 +327,45 @@ bool decl_is_defaulted_var(Decl *decl)
 	return decl->decl_kind == DECL_VAR && decl->var.no_init && decl->var.defaulted;
 }
 
+bool decl_may_be_generic(Decl *decl)
+{
+	switch (decl->decl_kind)
+	{
+		case DECL_POISONED:
+		case DECL_BODYPARAM:
+		case DECL_CT_ASSERT:
+		case DECL_CT_ECHO:
+		case DECL_CT_EXEC:
+		case DECL_CT_INCLUDE:
+		case DECL_ALIAS_PATH:
+		case DECL_ENUM_CONSTANT:
+		case DECL_ERASED:
+		case DECL_FAULT:
+		case DECL_GROUP:
+		case DECL_GENERIC:
+		case DECL_GENERIC_INSTANCE:
+		case DECL_IMPORT:
+		case DECL_LABEL:
+		case DECL_CONST_ENUM:
+			return false;
+		case DECL_ATTRIBUTE:
+		case DECL_BITSTRUCT:
+		case DECL_DECLARRAY:
+		case DECL_ALIAS:
+		case DECL_TYPEDEF:
+		case DECL_ENUM:
+		case DECL_FNTYPE:
+		case DECL_FUNC:
+		case DECL_MACRO:
+		case DECL_INTERFACE:
+		case DECL_STRUCT:
+		case DECL_TYPE_ALIAS:
+		case DECL_UNION:
+		case DECL_VAR:
+			return true;
+	}
+	UNREACHABLE
+}
 /*
  * Count the expected number of elements needed for an initializer
  * by folding any anonymous structs and unions.

src/compiler/compiler_internal.h

@@ -2382,6 +2382,7 @@ const char *decl_to_name(Decl *decl);
 const char *decl_to_a_name(Decl *decl);
 int decl_count_elements(Decl *structlike);
 bool decl_is_defaulted_var(Decl *decl);
+bool decl_may_be_generic(Decl *decl);
 void decl_append_links_to_global_during_codegen(Decl *decl);
 Decl *decl_template_get_generic(Decl *decl);
 

src/compiler/parse_global.c

@@ -1323,12 +1323,18 @@ static bool parse_attributes_for_global(ParseContext *c, Decl *decl)
 	bool is_builtin = false;
 	bool is_cond;
 	Decl *generics = NULL;
+	bool can_be_generic = decl_may_be_generic(decl);
 	if (!parse_attributes(c, &decl->attributes, &visibility, decl_needs_prefix(decl) ? &is_builtin : NULL, &is_cond, &generics)) return false;
 	if (generics)
 	{
+		if (!can_be_generic)
+		{
+			print_error_at(decl->span, "This declaration cannot be generic.");
+			return false;
+		}
 		parse_attach_generics(c, generics);
 	}
-	if (!generics && c->unit->default_generic_section)
+	if (!generics && c->unit->default_generic_section && can_be_generic)
 	{
 		generics = c->unit->default_generic_section;
 	}
@@ -2318,7 +2324,7 @@ static inline Decl *parse_alias_type(ParseContext *c, AstId contracts)
 {
 	advance_and_verify(c, TOKEN_ALIAS);
 
-	Decl *decl = decl_new(DECL_POISONED, symstr(c), c->span);
+	Decl *decl = decl_new(DECL_TYPE_ALIAS, symstr(c), c->span);
 	DEBUG_LOG("Parse def %s", decl->name);
 	if (!try_consume(c, TOKEN_TYPE_IDENT))
 	{

src/compiler/semantic_analyser.c

@@ -251,9 +251,6 @@ static void register_generic_decls(CompilationUnit *unit, Decl **decls)
 			case DECL_POISONED:
 				continue;
 			case DECL_FAULT:
-				PRINT_ERROR_AT(decl, "Generic modules cannot use 'faultdef', place the declaration in a separate sub module or parent module instead.");
-				decl_poison(decl);
-				break;
 			case DECL_BODYPARAM:
 			case DECL_DECLARRAY:
 			case DECL_ENUM_CONSTANT:

test/test_suite/generic/generic_fault.c3t

@@ -1,11 +1,11 @@
 module abc {Type};
 
 attrdef @Hello = @inline;
-faultdef ABC; // #error: Generic modules cannot use 'faultdef'
+faultdef ABC;
 
 module bcd;
-
+import abc;
 fn void main()
 {
-	Abc{int} a;
+	int? a = abc::ABC~;
 }

test/test_suite/generic/generic_fault2.c3t

@@ -0,0 +1,7 @@
+module g{T};
+
+faultdef F0, F1;
+
+module main;
+
+fn void main() {}