* actual extension callable, and the part before that refers to the receiver type (either fully
     * or partially qualified).
     *
     * For example, `foo.Foo.bar` may only refer to the extension callable `bar` with
     * a `foo.Foo` receiver type, and this function will only look for such combinations.
     *

        if (function.bodyBlockExpression != null) {
            // Given `fun f(...): R { blockExpression }`, `{ blockExpression }` is mapped to the enclosing anonymous function,
            // which may raise an exception if we attempt to retrieve, e.g., callable declaration from it.
            return null
        }
        if (function.typeReference == null) return null

                else -> KaFirGenericSubstitutor(substitutor, this@KaSymbolByFirBuilder)
            }
        }
    }

    /**
     * We shouldn't expose imported callables as they may have different [org.jetbrains.kotlin.name.CallableId]s
     * than the original callables.
     * Resolved FIR has explicitly declared original objects receivers instead of such synthetic callables.
     */

            // Because the file to compile may be contained in a "common" multiplatform module, an `expect` declaration doesn't necessarily
            // have an obvious associated `actual` symbol. `shouldStubOrphanedExpectSymbols` generates stubs for such `expect` declarations.
            shouldStubOrphanedExpectSymbols = true,

            is FirSpreadArgumentExpression -> {
                expression.convertConstantExpression(builder)
            }

            is FirVarargArgumentsExpression -> {
                // Vararg arguments may have multiple independent expressions associated.
                // Choose one to be the representative PSI value for the entire assembled argument.

                }
            }
        }
    }

    /**
     * Returns the set of [KtFile]s which may contain any of the found symbols. If a symbol is not contained in one of these files, the test
     * fails.
     */
    open fun getAllowedContainingFiles(mainFile: KtFile, testServices: TestServices): Set<KtFile> = setOf(mainFile)