Segregate loctrigs by callee

Sometimes multiple inference triggers occur on the same
source-code line, and it's better to keep them separated by callee.

src/parcel_snoopi_deep.jl

@@ -997,13 +997,17 @@ julia> accumulate_by_source(itrigs)
 ```
 """
 function accumulate_by_source(itrigs::AbstractVector{InferenceTrigger})
-    cs = Dict{Location,Vector{InferenceTrigger}}()
+    cs = IdDict{Tuple{Location,Any},Vector{InferenceTrigger}}()
     for itrig in itrigs
+        # Identify a trigger by both its location and what it calls, since some lines can have multiple callees
         loc = Location(itrig)
-        itrigs_loc = get!(Vector{InferenceTrigger}, cs, loc)
+        callee = MethodInstance(itrig.node)
+        ft = Base.unwrap_unionall(callee.specTypes).parameters[1]
+        f = ft <: Type ? ft.parameters[1] : ft.instance
+        itrigs_loc = get!(Vector{InferenceTrigger}, cs, (loc, f))
         push!(itrigs_loc, itrig)
     end
-    return sort([LocationTrigger(loc, itrigs_loc) for (loc, itrigs_loc) in cs]; by=loctrig->length(loctrig.itrigs))
+    return sort([LocationTrigger(loc, itrigs_loc) for ((loc, _), itrigs_loc) in cs]; by=loctrig->length(loctrig.itrigs))
 end
 
 function linetable_match(linetable::Vector{Core.LineInfoNode}, sffile::String, sffunc::String, sfline::Int)

test/snoopi_deep.jl

@@ -192,6 +192,17 @@ fdouble(x) = 2x
     show(io, loctrigs)
     @test any(str->occursin("4 callees from 2 callers", str), split(String(take!(io)), '\n'))
 
+    # Multiple callees on the same line
+    fline(x) = 2*x[]
+    gline(x) = x[]
+    fg(x) = fline(gline(x[]))
+    cc = Ref{Any}(Ref{Base.RefValue}(Ref(3)))
+    tinf = @snoopi_deep fg(cc)
+    itrigs = inference_triggers(tinf)
+    loctrigs = accumulate_by_source(itrigs)
+    @test length(loctrigs) == 2
+    loctrigs[1].loc == loctrigs[2].loc
+
     # Higher order function attribution
     @noinline function mymap!(f, dst, src)
         for i in eachindex(dst, src)