CS0266#

Cannot implicitly convert type 'Foo' to 'Bar'. An explicit conversion exists (are you missing a cast?)

Variables can only be assigned to one another if they follow some basic rules:

• The variable is the same type as the target.
• The variable inherits from the target type.
• The variable has an implicit conversion to the target type.
• There is a valid explicit cast made to the target type.

Resolution#

Often this error is shown when there's a misunderstanding of the types involved.

Floats and doubles#

3.2 is a double, 3.2f is a float. There is no implicit conversion from doubles to floats as there could be data loss converting from larger to smaller data.
If your code looks like:

public float gravity = -9.81; // Should be: -9.81f
position.x += 0.5; // Should be: 0.5f

Then you've likely failed to append the f to indicate the float type.

Other types#

Understand the types of the two objects involved in the error. Documentation and intellisense will help guide you to using the correct variables and syntax.

Examples:#

// Should be: transform.position;
// Transforms are not positions, they have positions.
Vector3 position = gameObject.transform;

// Should be: new Vector3(0, 1, 0);
// This isn't how a Vector3 is constructed.
Vector3 position = (0, 1, 0);

// Should be: GetComponentsInChildren<Example>();
// The singular version of the method has been mistaken for the plural.
Example[] data = GetComponentInChildren<Example>();

Sometimes this error can be due to a mistake made by using assignment instead of comparison:

// Should be: if (gameObject.name == "Example")
// Assignment "=" has been used instead of equality "=="
if (gameObject.name = "Example")
{
    ...
}