I downloaded the latest version of GT as of this post and attempted to run the command in the Playground (I assume that works? I haven't used GT before and have very little experience with Smalltalk), which threw the following error:
Returning an object but pool is fullFetched -> BaselineOfCarp-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Loading -> BaselineOfCarp-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Loaded -> BaselineOfCarp-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Loading baseline of BaselineOfCarp...
Fetched -> BaselineOfGToolkitFormatters-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- https://github.com/carpentry-org/gtoolkit-formatters.git[main]
Loading -> BaselineOfGToolkitFormatters-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- https://github.com/carpentry-org/gtoolkit-formatters.git[main]
Loaded -> BaselineOfGToolkitFormatters-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- https://github.com/carpentry-org/gtoolkit-formatters.git[main]
Project: GToolkit4SmaCC baseline
Project: SmaCC baseline
Project: GToolkitFormatters baseline
Fetched -> GToolkitFormatter-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- https://github.com/carpentry-org/gtoolkit-formatters.git[main]
Fetched -> GToolkitFormatter-Formatting-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- https://github.com/carpentry-org/gtoolkit-formatters.git[main]
Fetched -> Carp-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Fetched -> Carp-AST-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Fetched -> Carp-Parser-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- https://github.com/carpentry-org/gt4carp.git[master]
Loading -> GToolkitFormatter-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- cache
Loaded -> GToolkitFormatter-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- cache
Loading -> GToolkitFormatter-Formatting-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- cache
Loaded -> GToolkitFormatter-Formatting-CompatibleUserName.1667026732 --- https://github.com/carpentry-org/gtoolkit-formatters.git[main] --- cache
Loading -> Carp-CompatibleUserName.1667023701 --- https://github.com/carpentry-org/gt4carp.git[master] --- cache
UndefinedObject>>DoIt (TCarpExpressionNodeVisitor is Undeclared)
UndefinedObject>>DoIt (TCarpExpressionNodeVisitor is Undeclared)
CarpEsugSlideShow>>parserFor: (CarpParser is Undeclared)
GtCarpCoderModel>>bindAndExecute: (CarpParser is Undeclared)
GtCarpCoderModel>>computeAst: (CarpParser is Undeclared)
GtCarpCoderModel>>initializeAddOns: (CarpParser is Undeclared)
GtCarpCoderModel>>initializeAddOns: (GtCarpFormatter is Undeclared)
GtCarpCoderModel>>initializeAddOns: (CarpParser is Undeclared)
GtCarpCoderModel>>inspectTypeSpawningOn: (CarpParser is Undeclared)
GtCarpIDECoderModel>>save (CarpParser is Undeclared)
GtCarpNewFunctionCoderModel>>initializeAddOns: (CarpParser is Undeclared)
GtCarpNewFunctionCoderModel>>save (CarpParser is Undeclared)
LanguageLinkSettings class>>carpDefaultSettings (CarpParser is Undeclared)
GtSmaCCParserStyler class>>carpStyler: (CarpVariableNode is Undeclared)
GtSmaCCParserStyler class>>carpStyler: (CarpModuleOrTypeNode is Undeclared)
CarpExecutionResult>>parse (CarpParser is Undeclared)
CarpFile class>>coreLoadStatements (CarpParser is Undeclared)
CarpFile class>>coreLoadStatements (CarpListNode is Undeclared)
CarpFile class>>coreLoadStatements (CarpVariableNode is Undeclared)
CarpFile>>for: (CarpParser is Undeclared)
CarpPostMortemDebugger>>sourceStyler (CarpParser is Undeclared)
UndefinedObject>>DoIt (TCarpExpressionNodeVisitor is Undeclared)
UndefinedObject>>DoIt (TCarpExpressionNodeVisitor is Undeclared)