Module merge 

Docs and traits for struct merging.

Merge Behavior

The following will explain the merge behavior on the example of a single field.

Merge behavior of merge and merge_ref

Same Type

struct Src {
    test: T
}
struct Target {
    test: T
}

This will simply merge src.test into target.test:
target.test = src.test

Target is Optional

struct Src {
    test: T
}
struct Target {
    test: Option<T>
}

This will wrap src.test into an Option and merge it into target.test:
target.test = Some(src.test);

Source is Optional

struct Src {
    test: Option<T>
}
struct Target {
    test: T
}

This will only merge src.test into target.test if src.test is Some: \

if let Some(value) = src.test {
    target.test = value;
}

Traits

StructMerge

Merge another struct into Self.

StructMergeInto

Counterpart of StructMerge. This will merge Self into a given target.

StructMergeIntoRef

Counterpart of StructMergeRef. This will merge &Self into a given target.

StructMergeRef

Merge another borrowed struct into Self.