cgen: fix codegen for a fixed array init with different node types (fix

#23545) (#23547)

vlib/v/gen/c/cgen.v

@@ -2768,10 +2768,23 @@ fn (mut g Gen) expr_with_fixed_array(expr ast.Expr, got_type_raw ast.Type, expec
 		g.writeln('${styp} ${tmp_var};')
 		// [ foo(), foo() ]!
 		val_typ := g.table.value_type(got_type_raw)
+		val_styp := g.styp(val_typ)
+		val_sym := g.table.final_sym(val_typ)
+		prefix := if val_sym.kind !in [.array, .array_fixed] { '&' } else { '' }
 		for i, item_expr in expr.exprs {
-			g.write('memcpy(${tmp_var}[${i}], ')
+			g.write('memcpy(${prefix}${tmp_var}[${i}], ')
+			needs_addr := (item_expr is ast.CallExpr && !item_expr.return_type.is_ptr()
+				&& g.table.final_sym(item_expr.return_type).kind !in [.array, .array_fixed])
+				|| (item_expr is ast.InfixExpr && !item_expr.promoted_type.is_ptr())
+				|| item_expr is ast.StructInit
+			if needs_addr {
+				g.write('ADDR(${val_styp}, ')
+			}
 			g.expr(item_expr)
-			g.writeln(', sizeof(${g.styp(val_typ)}));')
+			if needs_addr {
+				g.write(')')
+			}
+			g.writeln(', sizeof(${val_styp}));')
 		}
 	} else if expr is ast.CallExpr {
 		// return var.call() where returns is option/result fixed array

vlib/v/tests/builtin_arrays/array_fixed_init_node_test.v

@@ -0,0 +1,50 @@
+module main
+
+import math.vec
+
+pub struct Bezier {
+pub mut:
+	points [4]vec.Vec2[f32]
+}
+
+pub fn (b Bezier) h3() vec.Vec2[f32] {
+	return b.points[2]
+}
+
+pub fn (b Bezier) h4() vec.Vec2[f32] {
+	return b.points[3]
+}
+
+pub fn (b Bezier) end() vec.Vec2[f32] {
+	return b.h4()
+}
+
+pub struct Path {
+pub mut:
+	segments [1024]Bezier
+	len      int // should be read-only
+}
+
+pub fn (mut p Path) add(b Bezier) {
+	assert p.len + 1 < 1024
+	p.segments[p.len] = b
+	p.len++
+}
+
+fn test_main() {
+	b1 := Bezier{
+		points: [vec.Vec2[f32]{100, 100}, vec.Vec2[f32]{120, 80},
+			vec.Vec2[f32]{200, 70}, vec.Vec2[f32]{400, 200}]!
+	}
+	b2 := Bezier{
+		points: [b1.end(), b1.h3() + vec.Vec2[f32]{0, 2 * 80}, vec.Vec2[f32]{200, 70},
+			b1.end() + vec.Vec2[f32]{400, 200}]!
+	}
+
+	mut path := Path{}
+
+	path.add(b1)
+	path.add(b2)
+
+	assert sizeof(path) == 32772
+}