checker, cgen: fix complex generic sumtype (fix #11392) (#11400)

vlib/v/checker/checker.v

@@ -1152,7 +1152,7 @@ pub fn (mut c Checker) struct_init(mut node ast.StructInit) ast.Type {
 							}
 						}
 					} else if expr_type != ast.void_type && expr_type_sym.kind != .placeholder {
-						c.check_expected(expr_type, field_info.typ) or {
+						c.check_expected(c.unwrap_generic(expr_type), c.unwrap_generic(field_info.typ)) or {
 							c.error('cannot assign to field `$field_info.name`: $err.msg',
 								field.pos)
 						}

vlib/v/gen/c/cgen.v

@@ -2029,8 +2029,17 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw ast.Type, expected_typ
 	exp_styp := g.typ(expected_type)
 	got_styp := g.typ(got_type)
 	if expected_type != ast.void_type {
-		expected_deref_type := if expected_is_ptr { expected_type.deref() } else { expected_type }
-		got_deref_type := if got_is_ptr { got_type.deref() } else { got_type }
+		unwrapped_expected_type := g.unwrap_generic(expected_type)
+		unwrapped_got_type := g.unwrap_generic(got_type)
+		unwrapped_exp_sym := g.table.get_type_symbol(unwrapped_expected_type)
+		unwrapped_got_sym := g.table.get_type_symbol(unwrapped_got_type)
+
+		expected_deref_type := if expected_is_ptr {
+			unwrapped_expected_type.deref()
+		} else {
+			unwrapped_expected_type
+		}
+		got_deref_type := if got_is_ptr { unwrapped_got_type.deref() } else { unwrapped_got_type }
 		if g.table.sumtype_has_variant(expected_deref_type, got_deref_type) {
 			mut is_already_sum_type := false
 			scope := g.file.scope.innermost(expr.position().pos)
@@ -2050,9 +2059,9 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw ast.Type, expected_typ
 				g.prevent_sum_type_unwrapping_once = true
 				g.expr(expr)
 			} else {
-				g.write_sumtype_casting_fn(got_type, expected_type)
-				fname := '${got_sym.cname}_to_sumtype_$exp_sym.cname'
-				g.call_cfn_for_casting_expr(fname, expr, expected_is_ptr, exp_sym.cname,
+				g.write_sumtype_casting_fn(unwrapped_got_type, unwrapped_expected_type)
+				fname := '${unwrapped_got_sym.cname}_to_sumtype_$unwrapped_exp_sym.cname'
+				g.call_cfn_for_casting_expr(fname, expr, expected_is_ptr, unwrapped_exp_sym.cname,
 					got_is_ptr, got_styp)
 			}
 			return

vlib/v/tests/generic_complex_sumtype_test.v

@@ -0,0 +1,145 @@
+struct Empty {}
+
+struct Node<T> {
+	value T
+	left  Tree<T>
+	right Tree<T>
+}
+
+type Tree<T> = Empty | Node<T>
+
+// return size(number of nodes) of BST
+fn size<T>(tree Tree<T>) int {
+	return match tree {
+		Empty { 0 }
+		Node<T> { 1 + size<T>(tree.left) + size<T>(tree.right) }
+	}
+}
+
+// insert a value to BST
+fn insert<T>(tree Tree<T>, x T) Tree<T> {
+	return match tree {
+		Empty {
+			Node<T>{x, tree, tree}
+		}
+		Node<T> {
+			if x == tree.value {
+				tree
+			} else if x < tree.value {
+				Node<T>{
+					...tree
+					left: insert<T>(tree.left, x)
+				}
+			} else {
+				Node<T>{
+					...tree
+					right: insert<T>(tree.right, x)
+				}
+			}
+		}
+	}
+}
+
+// whether able to find a value in BST
+fn search<T>(tree Tree<T>, x T) bool {
+	return match tree {
+		Empty {
+			false
+		}
+		Node<T> {
+			if x == tree.value {
+				true
+			} else if x < tree.value {
+				search<T>(tree.left, x)
+			} else {
+				search<T>(tree.right, x)
+			}
+		}
+	}
+}
+
+// find the minimal value of a BST
+fn min<T>(tree Tree<T>) T {
+	return match tree {
+		Empty {
+			1e100
+		}
+		Node<T> {
+			if tree.value < (min<T>(tree.left)) {
+				tree.value
+			} else {
+				min<T>(tree.left)
+			}
+		}
+	}
+}
+
+// delete a value in BST (if nonexistant do nothing)
+fn delete<T>(tree Tree<T>, x T) Tree<T> {
+	return match tree {
+		Empty {
+			tree
+		}
+		Node<T> {
+			if tree.left is Node<T> && tree.right is Node<T> {
+				if x < tree.value {
+					Node<T>{
+						...tree
+						left: delete<T>(tree.left, x)
+					}
+				} else if x > tree.value {
+					Node<T>{
+						...tree
+						right: delete<T>(tree.right, x)
+					}
+				} else {
+					Node<T>{
+						...tree
+						value: min<T>(tree.right)
+						right: delete<T>(tree.right, min<T>(tree.right))
+					}
+				}
+			} else if tree.left is Node<T> {
+				if x == tree.value {
+					tree.left
+				} else {
+					Node<T>{
+						...tree
+						left: delete<T>(tree.left, x)
+					}
+				}
+			} else {
+				if x == tree.value {
+					tree.right
+				} else {
+					Node<T>{
+						...tree
+						right: delete<T>(tree.right, x)
+					}
+				}
+			}
+		}
+	}
+}
+
+fn test_generics_complex_sumtype() {
+	mut tree := Tree<f64>(Empty{})
+	input := [0.3, 0.2, 0.5, 0.0, 0.6, 0.8, 0.9, 1.0, 0.1, 0.4, 0.7]
+	for i in input {
+		tree = insert(tree, i)
+	}
+	println('[1] after insertion tree size is ${size(tree)}') // 11
+	del := [-0.3, 0.0, 0.3, 0.6, 1.0, 1.5]
+	for i in del {
+		tree = delete(tree, i)
+	}
+	print('[2] after deletion tree size is ${size(tree)}, ') // 7
+	print('and these elements were deleted: ') // 0.0 0.3 0.6 1.0
+	for i in input {
+		if !search(tree, i) {
+			print('$i ')
+		}
+	}
+	println('')
+	assert size(tree) == 7
+}