[FIR] Resolve infix calls to infix functions only

Implements INFIX_MODIFIER_REQUIRED diagnostics

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -813,6 +813,13 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.INFIX_MODIFIER_REQUIRED) { firDiagnostic ->
+        InfixModifierRequiredImpl(
+            firSymbolBuilder.functionLikeBuilder.buildFunctionSymbol(firDiagnostic.a.fir),
+            firDiagnostic as FirPsiDiagnostic<*>,
+            token,
+        )
+    }
     add(FirErrors.INLINE_CLASS_NOT_TOP_LEVEL) { firDiagnostic ->
         InlineClassNotTopLevelImpl(
             firDiagnostic as FirPsiDiagnostic<*>,

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -586,6 +586,11 @@ sealed class KtFirDiagnostic<PSI: PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val name: String
     }
 
+    abstract class InfixModifierRequired : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = InfixModifierRequired::class
+        abstract val functionSymbol: KtFunctionLikeSymbol
+    }
+
     abstract class InlineClassNotTopLevel : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = InlineClassNotTopLevel::class
     }

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -938,6 +938,14 @@ internal class OperatorModifierRequiredImpl(
     override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
 }
 
+internal class InfixModifierRequiredImpl(
+    override val functionSymbol: KtFunctionLikeSymbol,
+    firDiagnostic: FirPsiDiagnostic<*>,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InfixModifierRequired(), KtAbstractFirDiagnostic<PsiElement> {
+    override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
+}
+
 internal class InlineClassNotTopLevelImpl(
     firDiagnostic: FirPsiDiagnostic<*>,
     override val token: ValidityToken,