fix partially_inline! with isdefined (#40628)

ref #40562 (comment)

Author: simeonschaub

base/meta.jl

@@ -370,7 +370,10 @@ function _partially_inline!(@nospecialize(x), slot_replacements::Vector{Any},
     if isa(x, Expr)
         head = x.head
         if head === :static_parameter
-            return QuoteNode(static_param_values[x.args[1]])
+            if isassigned(static_param_values, x.args[1])
+                return QuoteNode(static_param_values[x.args[1]])
+            end
+            return x
         elseif head === :cfunction
             @assert !isa(type_signature, UnionAll) || !isempty(spvals)
             if !isa(x.args[2], QuoteNode) # very common no-op
@@ -413,6 +416,30 @@ function _partially_inline!(@nospecialize(x), slot_replacements::Vector{Any},
             x.args[2] += statement_offset
         elseif head === :enter
             x.args[1] += statement_offset
+        elseif head === :isdefined
+            arg = x.args[1]
+            # inlining a QuoteNode or literal into `Expr(:isdefined, x)` is invalid, replace with true
+            if isa(arg, Core.SlotNumber)
+                id = arg.id
+                if 1 <= id <= length(slot_replacements)
+                    replacement = slot_replacements[id]
+                    if isa(replacement, Union{Core.SlotNumber, GlobalRef, Symbol})
+                        return Expr(:isdefined, replacement)
+                    else
+                        @assert !isa(replacement, Expr)
+                        return true
+                    end
+                end
+                return Expr(:isdefined, Core.SlotNumber(id + slot_offset))
+            elseif isexpr(arg, :static_parameter)
+                if isassigned(static_param_values, arg.args[1])
+                    return true
+                end
+                return x
+            else
+                @assert isa(arg, Union{GlobalRef, Symbol})
+                return x
+            end
         elseif !is_meta_expr_head(head)
             partially_inline!(x.args, slot_replacements, type_signature, static_param_values,
                               slot_offset, statement_offset, boundscheck)

test/meta.jl

@@ -241,7 +241,29 @@ ci = code_lowered(f, Tuple{Int})[1]
 
 g(::Val{x}) where {x} = x ? 1 : 0
 ci = code_lowered(g, Tuple{Val{true}})[1]
-@test Meta.partially_inline!(ci.code, [], Tuple{typeof(g),Val{true}}, Any[Val{true}], 0, 0, :propagate)[1] ==
-   Core.GotoIfNot(QuoteNode(Val{true}), 3)
-@test Meta.partially_inline!(ci.code, [], Tuple{typeof(g),Val{true}}, Any[Val{true}], 0, 2, :propagate)[1] ==
-   Core.GotoIfNot(QuoteNode(Val{true}), 5)
+@test Meta.partially_inline!(ci.code, [], Tuple{typeof(g),Val{true}}, Any[true], 0, 0, :propagate)[1] ==
+   Core.GotoIfNot(QuoteNode(true), 3)
+@test Meta.partially_inline!(ci.code, [], Tuple{typeof(g),Val{true}}, Any[true], 0, 2, :propagate)[1] ==
+   Core.GotoIfNot(QuoteNode(true), 5)
+
+@testset "inlining with isdefined" begin
+    isdefined_slot(x) = @isdefined(x)
+    ci = code_lowered(isdefined_slot, Tuple{Int})[1]
+    @test Meta.partially_inline!(copy(ci.code), [], Tuple{typeof(isdefined_slot), Int},
+                                 [], 0, 0, :propagate)[1] == Expr(:isdefined, Core.SlotNumber(2))
+    @test Meta.partially_inline!(copy(ci.code), [isdefined_slot, 1], Tuple{typeof(isdefined_slot), Int},
+                                 [], 0, 0, :propagate)[1] == true
+
+    isdefined_sparam(::T) where {T} = @isdefined(T)
+    ci = code_lowered(isdefined_sparam, Tuple{Int})[1]
+    @test Meta.partially_inline!(copy(ci.code), [], Tuple{typeof(isdefined_sparam), Int},
+                                 Any[Int], 0, 0, :propagate)[1] == true
+    @test Meta.partially_inline!(copy(ci.code), [], Tuple{typeof(isdefined_sparam), Int},
+                                 [], 0, 0, :propagate)[1] == Expr(:isdefined, Expr(:static_parameter, 1))
+
+    @eval isdefined_globalref(x) = $(Expr(:isdefined, GlobalRef(Base, :foo)))
+    ci = code_lowered(isdefined_globalref, Tuple{Int})[1]
+    @test Meta.partially_inline!(copy(ci.code), Any[isdefined_globalref, 1], Tuple{typeof(isdefined_globalref), Int},
+                                 [], 0, 0, :propagate)[1] == Expr(:isdefined, GlobalRef(Base, :foo))
+
+end