Final answer:
When the OCaml compiler cannot infer the type, it results in a type error, requiring the developer to provide explicit type annotations to resolve the ambiguity and ensure the program's type safety.
Step-by-step explanation:
If the OCaml compiler cannot infer the type, it will report a type error, indicating that it cannot deduce a compatible type for the given expression or variable. Type inference is a fundamental aspect of OCaml's type system, allowing the compiler to automatically determine the types of expressions without explicit type annotations from the programmer. However, in cases where the code is ambiguous or the type cannot be logically inferred, the programmer must resolve the ambiguity by providing explicit type annotations.
For instance, if you define a function but the types of its parameters cannot be determined based on its usage within the function, the OCaml compiler will raise an error. This is to ensure the type safety of the program. When faced with such an error, the developer should review the code and consider where additional type information is required, potentially annotating function parameters, variables, or expressions to guide the compiler.