FIR IDE: common super type of given KtExpression's

idea/idea-frontend-api/src/org/jetbrains/kotlin/idea/frontend/api/components/KtPsiTypeProvider.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtTypeReference
 
 public abstract class KtPsiTypeProvider : KtAnalysisSessionComponent() {
+    public abstract fun commonSuperType(expressions: Collection<KtExpression>, context: KtExpression, mode: TypeMappingMode): PsiType?
     public abstract fun getPsiTypeForKtExpression(expression: KtExpression, mode: TypeMappingMode): PsiType
     public abstract fun getPsiTypeForKtDeclaration(ktDeclaration: KtDeclaration, mode: TypeMappingMode): PsiType
     public abstract fun getPsiTypeForKtTypeReference(ktTypeReference: KtTypeReference, mode: TypeMappingMode): PsiType
@@ -23,6 +24,13 @@ public abstract class KtPsiTypeProvider : KtAnalysisSessionComponent() {
 }
 
 public interface KtPsiTypeProviderMixIn : KtAnalysisSessionMixIn {
+    public fun commonSuperType(
+        expressions: Collection<KtExpression>,
+        context: KtExpression,
+        mode: TypeMappingMode = TypeMappingMode.DEFAULT
+    ): PsiType? =
+        analysisSession.psiTypeProvider.commonSuperType(expressions, context, mode)
+
     public fun KtExpression.getPsiType(mode: TypeMappingMode = TypeMappingMode.DEFAULT): PsiType =
         analysisSession.psiTypeProvider.getPsiTypeForKtExpression(this, mode)
 

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/components/KtFirExpressionTypeProvider.kt

@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.idea.fir.low.level.api.api.getOrBuildFirSafe
 import org.jetbrains.kotlin.idea.frontend.api.components.KtExpressionTypeProvider
 import org.jetbrains.kotlin.idea.frontend.api.fir.KtFirAnalysisSession
 import org.jetbrains.kotlin.idea.frontend.api.fir.utils.getReferencedElementType
+import org.jetbrains.kotlin.idea.frontend.api.fir.utils.unwrap
 import org.jetbrains.kotlin.idea.frontend.api.tokens.ValidityToken
 import org.jetbrains.kotlin.idea.frontend.api.types.KtClassErrorType
 import org.jetbrains.kotlin.idea.frontend.api.types.KtType
@@ -43,15 +44,6 @@ internal class KtFirExpressionTypeProvider(
         }
     }
 
-    private fun KtExpression.unwrap(): KtExpression {
-        return when (this) {
-            is KtLabeledExpression -> baseExpression?.unwrap()
-            is KtAnnotatedExpression -> baseExpression?.unwrap()
-            is KtObjectLiteralExpression -> objectDeclaration
-            else -> null
-        } ?: this
-    }
-
     override fun getExpectedType(expression: PsiElement): KtType? {
         val expectedType = getExpectedTypeByReturnExpression(expression)
             ?: getExpressionTypeByIfOrBooleanCondition(expression)

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/components/KtFirPsiTypeProvider.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirGetClassCall
 import org.jetbrains.kotlin.fir.expressions.FirStatement
 import org.jetbrains.kotlin.fir.references.FirNamedReference
+import org.jetbrains.kotlin.fir.typeContext
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.idea.fir.low.level.api.api.getOrBuildFir
 import org.jetbrains.kotlin.idea.fir.low.level.api.api.getOrBuildFirOfType
@@ -32,15 +33,36 @@ internal class KtFirPsiTypeProvider(
     override val analysisSession: KtFirAnalysisSession,
     override val token: ValidityToken,
 ) : KtPsiTypeProvider(), KtFirAnalysisSessionComponent {
+
+    override fun commonSuperType(
+        expressions: Collection<KtExpression>,
+        context: KtExpression,
+        mode: TypeMappingMode
+    ): PsiType? = withValidityAssertion {
+        val unitType = analysisSession.rootModuleSession.builtinTypes.unitType.type
+        analysisSession.rootModuleSession.typeContext
+            .commonSuperTypeOrNull(expressions.map { e -> e.getConeType(unitType) { it } })
+            ?.asPsiType(mode, context)
+    }
+
     override fun getPsiTypeForKtExpression(
         expression: KtExpression,
         mode: TypeMappingMode,
     ): PsiType = withValidityAssertion {
-        when (val fir = expression.getOrBuildFir(firResolveState)) {
-            is FirExpression -> fir.typeRef.coneType.asPsiType(mode, expression)
-            is FirNamedReference -> fir.getReferencedElementType().asPsiType(mode, expression)
-            is FirStatement -> PsiType.VOID
-            else -> throwUnexpectedFirElementError(fir, expression)
+        expression.getConeType(PsiType.VOID) {
+            it.asPsiType(mode, expression)
+        }
+    }
+
+    private inline fun <T> KtExpression.getConeType(
+        defaultType: T,
+        coneTypeConverter: (ConeKotlinType) -> T,
+    ): T = withValidityAssertion {
+        when (val fir = this.getOrBuildFir(firResolveState)) {
+            is FirExpression -> coneTypeConverter(fir.typeRef.coneType)
+            is FirNamedReference -> coneTypeConverter(fir.getReferencedElementType())
+            is FirStatement -> defaultType
+            else -> throwUnexpectedFirElementError(fir, this)
         }
     }
 

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/utils/firUtils.kt

@@ -23,6 +23,19 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtSimpleConstantVa
 import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.KtUnsupportedConstantValue
 import org.jetbrains.kotlin.idea.frontend.api.types.KtTypeNullability
 import org.jetbrains.kotlin.idea.references.FirReferenceResolveHelper
+import org.jetbrains.kotlin.psi.KtAnnotatedExpression
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtLabeledExpression
+import org.jetbrains.kotlin.psi.KtObjectLiteralExpression
+
+internal fun KtExpression.unwrap(): KtExpression {
+    return when (this) {
+        is KtLabeledExpression -> baseExpression?.unwrap()
+        is KtAnnotatedExpression -> baseExpression?.unwrap()
+        is KtObjectLiteralExpression -> objectDeclaration
+        else -> null
+    } ?: this
+}
 
 internal fun FirNamedReference.getReferencedElementType(): ConeKotlinType {
     val symbols = when (this) {