- Distinct func type would not accept direct function address assign. #1287

releasenotes.md

@@ -29,6 +29,7 @@
 - `opt` project setting now properly documented.
 - Incorrect justify formatting of integers.
 - Assertion with duplicate function pointer signatures #1286
+- Distinct func type would not accept direct function address assign. #1287
 
 ### Stdlib changes
 

src/compiler/sema_casts.c

@@ -1193,7 +1193,17 @@ static bool rule_to_distinct(CastContext *cc, bool is_explicit, bool is_silent)
 	assert(from_type == from_type->canonical);
 	Type *flat = type_flatten(cc->to);
 	ConvGroup flat_group = type_to_group(flat);
-	if (sema_cast_const(cc->expr))
+	Expr *expr = cc->expr;
+	bool is_const = sema_cast_const(expr);
+	// Allow DistinctFooFn a = &myfunc;
+	if (!is_const && from_type->type_kind == TYPE_FUNC_PTR
+		&& expr->expr_kind == EXPR_UNARY && expr->unary_expr.operator == UNARYOP_ADDR
+		&& expr->unary_expr.expr->expr_kind == EXPR_IDENTIFIER
+		&& expr->unary_expr.expr->identifier_expr.decl->decl_kind == DECL_FUNC)
+	{
+		is_const = true;
+	}
+	if (is_const)
 	{
 		cc->to = flat;
 		cc->to_group = flat_group;

test/test_suite/distinct/distinct_function.c3t

@@ -0,0 +1,14 @@
+module output;
+
+def FnA = fn void(int*);
+distinct FnB = FnA;
+
+fn void func(int*) {}
+
+fn void main()
+{
+    FnA a = &func;
+    FnB b = (FnB)&func;
+    FnB b2 = &func;
+    FnB b3 = fn (int* x) {};
+}