newLang := Language{Code: "omitmany2many", Name: "omitmany2many"}
	if err := DB.Model(&user).Omit("Languages.*").Association("Languages").Replace(&newLang); err == nil {
		t.Errorf("should failed to insert languages due to constraint failed, error: %v", err)
	}
}

func TestMany2ManyAssociationForSlice(t *testing.T) {
	users := []User{
		*GetUser("slice-many2many-1", Config{Languages: 2}),

   * {@code ClassCastException} for any elements {@code e1} and {@code e2} in the multiset. If the
   * user attempts to add an element to the multiset that violates this constraint (for example, the
   * user attempts to add a string element to a set whose elements are integers), the {@code
   * add(Object)} call will throw a {@code ClassCastException}.
   *

    /**
     * Parses the specified version constraint specification, for example "1.0" or "[1.0,2.0)".
     * <p>
     * Shortcut for {@code getService(VersionParser.class).parseVersionConstraint(...)}.
     *
     * @param versionConstraint the version string to parse
     * @return the version constraint parsed from the given string

	n := typ.NumMethods()
	list := make([]string, n)
	for i := range list {
		list[i] = typ.Method(i).Name()
	}
	sort.Strings(list)
	return list
}

// sortedEmbeddeds returns constraint types embedded in an
// interface. It does not include embedded interface types or methods.
func (w *Walker) sortedEmbeddeds(typ *types.Interface) []string {
	n := typ.NumEmbeddeds()
	list := make([]string, 0, n)

the use of cgo, and to 0 to disable it. The go tool will set the
build constraint "cgo" if cgo is enabled. The special import "C"
implies the "cgo" build constraint, as though the file also said
"//go:build cgo".  Therefore, if cgo is disabled, files that import
"C" will not be built by the go tool. (For more about build constraints
see https://golang.org/pkg/go/build/#hdr-Build_Constraints).

// (booleans, numbers, strings, pointers, channels, arrays of comparable types,
// structs whose fields are all comparable types).
// The comparable interface may only be used as a type parameter constraint,
// not as the type of a variable.
type comparable interface{ comparable }

// iota is a predeclared identifier representing the untyped integer ordinal

pkg go/build/constraint, type AndExpr struct, Y Expr
pkg go/build/constraint, type Expr interface, Eval(func(string) bool) bool
pkg go/build/constraint, type Expr interface, String() string
pkg go/build/constraint, type Expr interface, unexported methods
pkg go/build/constraint, type NotExpr struct
pkg go/build/constraint, type NotExpr struct, X Expr
pkg go/build/constraint, type OrExpr struct

There can be several approaches to achieve this, and I'll tell you more about specific strategies in the next chapters, for example when talking about Docker and containers.

The main constraint to consider is that there has to be a **single** component handling the **port** in the **public IP**. And then it has to have a way to **transmit** the communication to the replicated **processes/workers**.

		payload, err := io.ReadAll(io.LimitReader(r.Body, maxLocationConstraintSize))
		if err != nil {
			authZLogIf(ctx, err, logger.ErrorKind)
			return ErrMalformedXML
		}

		// Populate payload to extract location constraint.
		r.Body = io.NopCloser(bytes.NewReader(payload))
		region, s3Err = parseLocationConstraint(r)
		if s3Err != ErrNone {
			return s3Err
		}

		// Populate payload again to handle it in HTTP handler.

 *  Fix: Don't silently ignore calls to `EventSource.cancel()` made from
    `EventSourceListener.onOpen()`.
 *  Fix: Enforce the max intermediates constraint when using pinned certificates with Conscrypt.
    This impacts Conscrypt when the server's presented certificates form both a trusted-but-unpinned
    chain and an untrusted-but-pinned chain.