Is this the right way to remove highlight errors for Composables that are using

ExperimentalMaterialApi

? The project is KMP, I know the

sourceSets.all.lanaguageSettings

is the multiplatform way, but both are not working for me, not sure what is the issue but I can only remove the error by adding the

OptInt(...)

to the composable function

tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
    kotlinOptions.freeCompilerArgs += "-opt-in=androidx.compose.material.ExperimentalMaterialApi"
}

kotlin {
    android()
    jvm()

    sourceSets {
        all {
            languageSettings.optIn("androidx.compose.material.ExperimentalMaterialApi")
        }
        ...
    }
}

Maybe you also need the OptIn itself?

languageSettings.optIn("kotlin.RequiresOptIn")

I am going to try

Hmm... this is what I use in the root build.gradle of my project:

subprojects {
  plugins.withType<org.jetbrains.kotlin.gradle.plugin.KotlinMultiplatformPluginWrapper> {
    configure<org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension> {
      sourceSets.all {
        languageSettings {
          optIn("kotlin.RequiresOptIn")
          optIn("kotlin.ExperimentalStdlibApi")
          // remaining opt-ins
        }
      }
    }
  }
}

dunno why

languageSettings.optIn

doesn't work, but

kotlin {
    targets.all {
        compilations.all {
            kotlinOptions.freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
        }
    }
}

should

nop 😕

Your first example is missing the

X

from

-X

, but languageSettings should work 🤔

I copied from the docs, but I usually see it with -X too