Stack overflow when calling a function named f outside the RGF

using RuntimeGeneratedFunctions
RuntimeGeneratedFunctions.init(@__MODULE__)

f(x) = x + 1

rgf = @RuntimeGeneratedFunction(:(function(x); f(x); end))

rgf(3)

errors dramatically with

julia> rgf(3)  # StackOverflowError: f resolves to the RGF itself, not Main.f
Warning: detected a stack overflow; program state may be corrupted, so further execution might be unreliable.
ERROR: StackOverflowError:
Stacktrace:
      [1] generated_callfunc(f::RuntimeGeneratedFunction{…}, __args::Int64)
        @ Main ./none:0
      [2] (::RuntimeGeneratedFunction{…})(args::Int64)
        @ RuntimeGeneratedFunctions ~/jl/RuntimeGeneratedFunctions.jl/src/RuntimeGeneratedFunctions.jl:230
      [3] macro expansion
        @ ./REPL[4]:1 [inlined]
      [4] macro expansion
        @ ~/jl/RuntimeGeneratedFunctions.jl/src/RuntimeGeneratedFunctions.jl:243 [inlined]
      [5] macro expansion
        @ ./none:0 [inlined]
--- the above 5 lines are repeated 39990 more times ---
 [199956] generated_callfunc(f::RuntimeGeneratedFunction{…}, __args::Int64)
        @ Main ./none:0
Some type information was truncated. Use `show(err)` to see complete types.

If the arity of the RGF and the externally defined f is different, then it segfaults instead of overflowing because of #100.

I think this is because inside the RGF body, f refers to the RGF itself:

RuntimeGeneratedFunctions.jl/src/RuntimeGeneratedFunctions.jl

Lines 401 to 409 in 73411b2

    
           @inline @generated function $RuntimeGeneratedFunctions.generated_callfunc( 
        
                   f::$RuntimeGeneratedFunctions.RuntimeGeneratedFunction{ 
        
                       argnames, 
        
                       cache_tag, 
        
                       $_tagname, 
        
                       id, 
        
                   }, 
        
                   __args... 
        
               ) where {

Different error if you use __args because of the same root cause:

julia> __args(x) = x + 1
__args (generic function with 1 method)

julia> rgf = @RuntimeGeneratedFunction(:(function(x); __args(x); end))
RuntimeGeneratedFunction(#=in Main=#, #=using Main=#, :((x,)->begin
          #= REPL[4]:1 =#
          #= REPL[4]:1 =#
          __args(x)
      end))

julia> rgf(3)
ERROR: MethodError: objects of type Tuple{Int64} are not callable
The object of type `Tuple{Int64}` exists, but no method is defined for this combination of argument types when trying to treat it as a callable object.
Stacktrace:
 [1] macro expansion
   @ ./REPL[4]:1 [inlined]
 [2] macro expansion
   @ ~/jl/RuntimeGeneratedFunctions.jl/src/RuntimeGeneratedFunctions.jl:243 [inlined]
 [3] macro expansion
   @ ./none:0 [inlined]
 [4] generated_callfunc(f::RuntimeGeneratedFunction{…}, __args::Int64)
   @ Main ./none:0
 [5] (::RuntimeGeneratedFunction{…})(args::Int64)
   @ RuntimeGeneratedFunctions ~/jl/RuntimeGeneratedFunctions.jl/src/RuntimeGeneratedFunctions.jl:230
 [6] top-level scope
   @ REPL[5]:1
 [7] top-level scope
   @ REPL:1
Some type information was truncated. Use `show(err)` to see complete types.

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Stack overflow when calling a function named `f` outside the RGF #146

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	@inline @generated function $RuntimeGeneratedFunctions.generated_callfunc(
	f::$RuntimeGeneratedFunctions.RuntimeGeneratedFunction{
	argnames,
	cache_tag,
	$_tagname,
	id,
	},
	__args...
	) where {

Stack overflow when calling a function named f outside the RGF #146

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penelopeysm commented on Aug 21, 2026

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Stack overflow when calling a function named `f` outside the RGF #146