[Semantic API] Type of enums returned as UNION

[shehan360]

Description:
When we have reference to a enum, the semantic api returns the type as a UNION.
We have added enums to docs, and need this functionality to recognize enums in order to create links.

Steps to reproduce:

1. Have the following code

public enum LogLevel {
    DEBUG,
    ERROR,
    INFO,
    TRACE,
    # log level of warn
    WARN,
    ALL,
    # Turn off logging
    OFF
}
public type TestRecord record {
    boolean http2PriorKnowledge = false;
    LogLevel lvl;
};
2. Get the symbol of LogLevel in TestRecord.
3. TypeDescriptor.kind() returns `UNION`

Affected Versions:

OS, DB, other environment details and versions:

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[pubudu91]

@shehan360 I had a look at this. This is actually by design. The spec defines enums as follows:

module-enum-decl :=
   metadata
   [public] enum identifier { enum-member (, enum-member)* }

The spec also says the following:

The identifier is defined as a type in the same was as if it had been defined by a module-type-defn, with the type-descriptor being the union of the constants defined by the members.

So the above enum is actually the same as

public const DEBUG = "DEBUG";
public const ERROR = "ERROR";
public const INFO = "INFO";
public const TRACE = "TRACE";
public const WARN = "WARN";
public const ALL = "ALL";
public const OFF = "OFF";

public type LogLevel DEBUG|ERROR|INFO|TRACE|WARN|ALL|OFF;

This is why when you call typeDescriptor() on an enum type ref you get a union type descriptor.

At the moment, to get the associated enum symbol, you look it up by passing the location in the type ref symbol to symbol(). I initiated a discussion on whether to add a back reference to the type def as well: #27980

[shehan360]

There are several broken links in api docs due to this issue. It would be great if we can get a fix for this.

[pubudu91]

Doesn't the above mentioned approach work? You don't need to get the typedesc of the type ref of an enum right?

[pubudu91]

As mentioned in #27980, we decided to add a method to TypeReferenceTypeSymbol to get the definition symbol associated with the type ref. This would solve this issue as well right?

[shehan360]

As mentioned in #27980, we decided to add a method to TypeReferenceTypeSymbol to get the definition symbol associated with the type ref. This would solve this issue as well right?

Yes I think it will resolve the issue.