Unions with member names matching auto-imported Kotlin symbols fail to codegen correctly

[ianbotsf]

Describe the bug

Given a model such as:

union Foo {
    list: BarList
}

list BarList {
    member: Bar
}

string Bar

The generated code will make no attempt to differentiate between the union member Foo.List and the collection kotlin.collections.List:

public sealed class Foo {
    public data class List(val value: List<kotlin.String>) : Foo () { // Compilation error: `List` has no generic args
    }
}

We need smarter handling of Kotlin symbols when codegenning union members (and possibly elsewhere too).

Expected behavior

Shapes should codegen and compile successfully

Current behavior

Compilation fails

Steps to Reproduce

See above model

Possible Solution

No response

Context

No response

Smithy-Kotlin version

1.2.18

Platform (JVM/JS/Native)

JVM

Operating system and version

(n/a)