[REPLCompletions] improve REPLInterpreter effects of dict operations (

#52347)

This should allow more completions for cases involving dict operations.

base/dict.jl

@@ -271,7 +271,7 @@ function empty!(h::Dict{K,V}) where V where K
 end
 
 # get the index where a key is stored, or -1 if not present
-@assume_effects :terminates_locally function ht_keyindex(h::Dict{K,V}, key) where V where K
+function ht_keyindex(h::Dict{K,V}, key) where V where K
     isempty(h) && return -1
     sz = length(h.keys)
     iter = 0
@@ -280,9 +280,9 @@ end
     index, sh = hashindex(key, sz)
     keys = h.keys
 
-    @inbounds while true
+    @assume_effects :terminates_locally :noub @inbounds while true
         isslotempty(h,index) && return -1
-        if h.slots[index] == sh
+        if sh == h.slots[index]
             k = keys[index]
             if (key ===  k || isequal(key, k))
                 return index
@@ -507,7 +507,7 @@ end
 
 function getindex(h::Dict{K,V}, key) where V where K
     index = ht_keyindex(h, key)
-    @inbounds return (index < 0) ? throw(KeyError(key)) : h.vals[index]::V
+    return index < 0 ? throw(KeyError(key)) : @assume_effects :noub @inbounds h.vals[index]::V
 end
 
 """

stdlib/REPL/test/replcompletions.jl

@@ -2156,3 +2156,21 @@ let t = REPLCompletions.repl_eval_ex(:(Base.PersistentDict(issue52099 => 3)), @_
         @test length(t.val) == 1
     end
 end
+
+# test REPLInterpreter effects for `getindex(::Dict, key)`
+for (DictT, KeyT) = Any[(Dict{Symbol,Any}, Symbol),
+                        (Dict{Int,Any}, Int),
+                        (Dict{String,Any}, String)]
+    @testset let DictT=DictT, KeyT=KeyT
+        effects = Base.infer_effects(getindex, (DictT,KeyT); interp=REPL.REPLCompletions.REPLInterpreter())
+        @test Core.Compiler.is_effect_free(effects)
+        @test Core.Compiler.is_terminates(effects)
+        @test Core.Compiler.is_noub(effects)
+        effects = Base.infer_effects((DictT,KeyT); interp=REPL.REPLCompletions.REPLInterpreter()) do d, key
+            key in keys(d)
+        end
+        @test Core.Compiler.is_effect_free(effects)
+        @test Core.Compiler.is_terminates(effects)
+        @test Core.Compiler.is_noub(effects)
+    end
+end