From 68ff835b856471391a49c68636bcdd46063d5b9f Mon Sep 17 00:00:00 2001
From: Shuhei Kadowaki <40514306+aviatesk@users.noreply.github.com>
Date: Thu, 14 Jul 2022 08:14:59 +0900
Subject: [PATCH] mark `Symbol(::String)` as `:foldable` method (#46014)

---
 base/boot.jl | 19 +++++++++++++++----
 test/core.jl |  4 ++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/base/boot.jl b/base/boot.jl
index 057767db295fe..ddf82b9823453 100644
--- a/base/boot.jl
+++ b/base/boot.jl
@@ -453,6 +453,18 @@ convert(::Type{T}, x::T) where {T} = x
 cconvert(::Type{T}, x) where {T} = convert(T, x)
 unsafe_convert(::Type{T}, x::T) where {T} = x
 
+_is_internal(__module__) = __module__ === Core
+# can be used in place of `@assume_effects :foldable` (supposed to be used for bootstrapping)
+macro _foldable_meta()
+    return _is_internal(__module__) && Expr(:meta, Expr(:purity,
+        #=:consistent=#true,
+        #=:effect_free=#true,
+        #=:nothrow=#false,
+        #=:terminates_globally=#true,
+        #=:terminates_locally=#false,
+        #=:notaskstate=#false))
+end
+
 const NTuple{N,T} = Tuple{Vararg{T,N}}
 
 ## primitive Array constructors
@@ -480,7 +492,6 @@ Array{T}(::UndefInitializer, d::NTuple{N,Int}) where {T,N} = Array{T,N}(undef, d
 # empty vector constructor
 Array{T,1}() where {T} = Array{T,1}(undef, 0)
 
-
 (Array{T,N} where T)(x::AbstractArray{S,N}) where {S,N} = Array{S,N}(x)
 
 Array(A::AbstractArray{T,N})    where {T,N}   = Array{T,N}(A)
@@ -489,12 +500,12 @@ Array{T}(A::AbstractArray{S,N}) where {T,N,S} = Array{T,N}(A)
 AbstractArray{T}(A::AbstractArray{S,N}) where {T,S,N} = AbstractArray{T,N}(A)
 
 # primitive Symbol constructors
-eval(Core, :(function Symbol(s::String)
-    $(Expr(:meta, :pure))
+function Symbol(s::String)
+    @_foldable_meta
     return ccall(:jl_symbol_n, Ref{Symbol}, (Ptr{UInt8}, Int),
                  ccall(:jl_string_ptr, Ptr{UInt8}, (Any,), s),
                  sizeof(s))
-end))
+end
 function Symbol(a::Array{UInt8,1})
     return ccall(:jl_symbol_n, Ref{Symbol}, (Ptr{UInt8}, Int),
                  ccall(:jl_array_ptr, Ptr{UInt8}, (Any,), a),
diff --git a/test/core.jl b/test/core.jl
index ddd501412955a..dfb7414e034a8 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -7808,3 +7808,7 @@ end
 import .Foo45350: x45350
 f45350() = (global x45350 = 2)
 @test_throws ErrorException f45350()
+
+@testset "effect override on Symbol(::String)" begin
+    @test Core.Compiler.is_foldable(Base.infer_effects(Symbol, (String,)))
+end