From 9e71e324eb487fc70806131ceebd8a1070035763 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 14 Dec 2024 13:52:40 -0300
Subject: [PATCH] cgen: fix assert for alias to fixed array (fix #23149)
 (#23161)

---
 vlib/v/ast/types.v                     | 10 ++++++++++
 vlib/v/gen/c/auto_eq_methods.v         |  5 +++++
 vlib/v/gen/c/infix.v                   | 17 +++++++++++++++++
 vlib/v/gen/c/str.v                     |  4 ++++
 vlib/v/tests/assert_alias_array_test.v | 18 ++++++++++++++++++
 5 files changed, 54 insertions(+)
 create mode 100644 vlib/v/tests/assert_alias_array_test.v

diff --git a/vlib/v/ast/types.v b/vlib/v/ast/types.v
index ee1e4f168e947e..832521cb1feef0 100644
--- a/vlib/v/ast/types.v
+++ b/vlib/v/ast/types.v
@@ -1006,6 +1006,16 @@ pub fn (t &Struct) is_unresolved_generic() bool {
 	return t.generic_types.len > 0 && t.concrete_types.len == 0
 }
 
+pub fn (t &TypeSymbol) is_primitive_fixed_array() bool {
+	if t.info is ArrayFixed {
+		return global_table.final_sym(t.info.elem_type).is_primitive()
+	} else if t.info is Alias {
+		return global_table.final_sym(t.info.parent_type).is_primitive_fixed_array()
+	} else {
+		return false
+	}
+}
+
 pub fn (t &TypeSymbol) is_array_fixed() bool {
 	if t.info is ArrayFixed {
 		return true
diff --git a/vlib/v/gen/c/auto_eq_methods.v b/vlib/v/gen/c/auto_eq_methods.v
index 429319702aa11b..330fbb3b98bc78 100644
--- a/vlib/v/gen/c/auto_eq_methods.v
+++ b/vlib/v/gen/c/auto_eq_methods.v
@@ -437,6 +437,11 @@ fn (mut g Gen) gen_fixed_array_equality_fn(left_type ast.Type) string {
 
 	mut fn_builder := strings.new_builder(512)
 	fn_builder.writeln('inline bool ${ptr_styp}_arr_eq(${arg_styp} a, ${arg_styp} b) {')
+	if left_typ.sym.is_primitive_fixed_array() {
+		fn_builder.writeln('\tif (!memcmp(${left}, ${right}, sizeof(${arg_styp}))) {')
+		fn_builder.writeln('\t\treturn true;')
+		fn_builder.writeln('\t}')
+	}
 	fn_builder.writeln('\tfor (int i = 0; i < ${size}; ++i) {')
 	// compare every pair of elements of the two fixed arrays
 	if elem.sym.kind == .string {
diff --git a/vlib/v/gen/c/infix.v b/vlib/v/gen/c/infix.v
index 9a50f45c6e1a39..c33b40a131d79b 100644
--- a/vlib/v/gen/c/infix.v
+++ b/vlib/v/gen/c/infix.v
@@ -216,8 +216,17 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 					if left.typ.is_ptr() {
 						g.write('*'.repeat(left.typ.nr_muls()))
 					}
+					if node.left is ast.StructInit && left.unaliased_sym.is_primitive_fixed_array() {
+						s := g.styp(left.unaliased)
+						g.write('(${s})')
+					}
 					g.expr(node.left)
 					g.write(', ')
+					if node.right is ast.StructInit
+						&& right.unaliased_sym.is_primitive_fixed_array() {
+						s := g.styp(right.unaliased)
+						g.write('(${s})')
+					}
 					if right.typ.is_ptr() {
 						g.write('*'.repeat(right.typ.nr_muls()))
 					}
@@ -266,6 +275,10 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 						s := g.styp(left.unaliased)
 						g.write('(${s})')
 					}
+				} else if node.left is ast.StructInit
+					&& left.unaliased_sym.is_primitive_fixed_array() {
+					s := g.styp(left.unaliased)
+					g.write('(${s})')
 				}
 				g.expr(node.left)
 				g.write(', ')
@@ -274,6 +287,10 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 						s := g.styp(right.unaliased)
 						g.write('(${s})')
 					}
+				} else if node.right is ast.StructInit
+					&& right.unaliased_sym.is_primitive_fixed_array() {
+					s := g.styp(right.unaliased)
+					g.write('(${s})')
 				}
 				g.expr(node.right)
 				g.write(')')
diff --git a/vlib/v/gen/c/str.v b/vlib/v/gen/c/str.v
index b3b818fc983809..37c6bc80f8597b 100644
--- a/vlib/v/gen/c/str.v
+++ b/vlib/v/gen/c/str.v
@@ -234,6 +234,10 @@ fn (mut g Gen) gen_expr_to_string(expr ast.Expr, etype ast.Type) {
 			if temp_var_needed {
 				g.write(tmp_var)
 			} else {
+				if expr is ast.StructInit && g.table.final_sym(expr.typ).is_primitive_fixed_array() {
+					s := g.styp(expr.typ)
+					g.write('(${s})')
+				}
 				g.expr_with_cast(expr, typ, typ)
 			}
 		} else if typ.has_flag(.option) {
diff --git a/vlib/v/tests/assert_alias_array_test.v b/vlib/v/tests/assert_alias_array_test.v
new file mode 100644
index 00000000000000..c89aa00d7887ff
--- /dev/null
+++ b/vlib/v/tests/assert_alias_array_test.v
@@ -0,0 +1,18 @@
+type Arr = [4]u8
+type Arr2 = []u8
+type ArrStr = [4]string
+
+fn test_main() {
+	a := Arr{}
+	b := Arr{}
+
+	assert a == b
+	assert Arr{} == Arr{}
+	assert Arr{} == [4]u8{}
+	assert Arr{} == [u8(0), 0, 0, 0]!
+
+	assert Arr2{} == Arr2{}
+	assert Arr2{} == []u8{}
+
+	assert ArrStr{} == ArrStr{}
+}