Type of '<variablename>' cannot be inferred from an expression containing '<variablename>'

The compiler cannot infer the data type of a variable if the variable is used in establishing its initial value in the declaration.

For example, with Option Infer set to On, the following examples do not compile:

Declarations

' Does not compile with Option Infer on.
Dim m = m
Dim d = someFunction(d)

For loop

' Does not compile with Option Infer on.
For j = 1 To j
Next

For Each loop

' Does not compile with Option Infer on.
For Each customer In customer.Orders
Next

Error ID: BC30980

If the two variables were intended to refer to different values, change the name of the variable that you are declaring.
Use a literal value instead of the variable name in the initial value, on the right side of the assignment.
Use an As clause to specify the type of the variable you are declaring.

See Also