`--showConfig` does not include `files` field

[zaverden]

Steps to reproduce

tsc --showConfig vs tsgo --showConfig

    "@typescript/native-preview": "7.0.0-dev.20260404.1",
    "typescript": "6.0.0-dev.20260401"

tsc outputs resolved list of files

Behavior with typescript@6.0

{
    "compilerOptions": {
        "declaration": false,
        "declarationMap": false,
        "exactOptionalPropertyTypes": false,
        "isolatedModules": true,
        "jsx": "react-jsx",
        "module": "nodenext",
        "moduleDetection": "force",
        "moduleResolution": "nodenext",
        "noUncheckedIndexedAccess": true,
        "noUncheckedSideEffectImports": true,
        "outDir": "./build",
        "preserveConstEnums": true,
        "rootDir": "./src",
        "skipLibCheck": true,
        "sourceMap": true,
        "strict": true,
        "target": "esnext",
        "types": [
            "node"
        ],
        "verbatimModuleSyntax": true
    },
    "exclude": [
        "/home/zaverden/tmp/tsgo-test/build"
    ],
    "files": [
        "./src/index.ts",
        "./src/bin/tool.ts"
    ]
}

Behavior with tsgo

{
    "compilerOptions": {
        "declaration": false,
        "declarationMap": false,
        "exactOptionalPropertyTypes": false,
        "isolatedModules": true,
        "jsx": "react-jsx",
        "module": "nodenext",
        "moduleDetection": "force",
        "moduleResolution": "nodenext",
        "noUncheckedIndexedAccess": true,
        "noUncheckedSideEffectImports": true,
        "outDir": "./build",
        "preserveConstEnums": true,
        "rootDir": "./src",
        "skipLibCheck": true,
        "sourceMap": true,
        "strict": true,
        "target": "esnext",
        "types": [
            "node"
        ],
        "verbatimModuleSyntax": true
    },
    "exclude": [
        "/home/zaverden/tmp/tsgo-test/build"
    ]
}

[jakebailey]

Funnily, the original code was not written with the intent that this work, but behaved this way due to a bug!