diff --git a/base/compiler/abstractinterpretation.jl b/base/compiler/abstractinterpretation.jl
index 3c0f3336d64358..46e15d0c3ad79e 100644
--- a/base/compiler/abstractinterpretation.jl
+++ b/base/compiler/abstractinterpretation.jl
@@ -1709,7 +1709,7 @@ function abstract_apply(interp::AbstractInterpreter, argtypes::Vector{Any}, si::
     return CallMeta(res, exct, effects, retinfo)
 end
 
-function argtype_by_index(argtypes::Vector{Any}, i::Integer)
+function argtype_by_index(argtypes::Vector{Any}, i::Int)
     n = length(argtypes)
     na = argtypes[n]
     if isvarargtype(na)
@@ -2880,12 +2880,12 @@ end
 struct BestguessInfo{Interp<:AbstractInterpreter}
     interp::Interp
     bestguess
-    nargs::UInt
+    nargs::Int
     slottypes::Vector{Any}
     changes::VarTable
-    function BestguessInfo(interp::Interp, @nospecialize(bestguess), nargs::UInt,
+    function BestguessInfo(interp::Interp, @nospecialize(bestguess), nargs::Int,
         slottypes::Vector{Any}, changes::VarTable) where Interp<:AbstractInterpreter
-        new{Interp}(interp, bestguess, Int(nargs), slottypes, changes)
+        new{Interp}(interp, bestguess, nargs, slottypes, changes)
     end
 end
 
diff --git a/base/compiler/inferenceresult.jl b/base/compiler/inferenceresult.jl
index 8d8aec04628533..7da96c4cc2e93c 100644
--- a/base/compiler/inferenceresult.jl
+++ b/base/compiler/inferenceresult.jl
@@ -36,44 +36,44 @@ function pick_const_arg(𝕃::AbstractLattice, @nospecialize(given_argtype), @no
             # declared method signature, narrow it down using `tmeet`
             given_argtype = tmeet(𝕃, given_argtype, cache_argtype)
         end
+        return given_argtype
     else
-        given_argtype = cache_argtype
+        return cache_argtype
     end
-    return given_argtype
 end
 
 function pick_const_args!(𝕃::AbstractLattice, given_argtypes::Vector{Any}, cache_argtypes::Vector{Any})
-    if length(given_argtypes) == 0 || length(cache_argtypes) == 0
+    ngiven = length(given_argtypes)
+    ncache = length(cache_argtypes)
+    if ngiven == 0 || ncache == 0
         return Any[]
     end
     given_va = given_argtypes[end]
     cache_va = cache_argtypes[end]
     if isvarargtype(given_va)
-        ngiven = length(given_argtypes)
         va = unwrapva(given_va)
         if isvarargtype(cache_va)
             # Process the common prefix, then join
-            nprocessargs = max(length(given_argtypes)-1, length(cache_argtypes)-1)
+            nprocessargs = max(ngiven-1, ncache-1)
             resize!(given_argtypes, nprocessargs+1)
-            given_argtypes[end] = Vararg{pick_const_arg(𝕃, unwrapva(given_va), unwrapva(cache_va))}
+            given_argtypes[end] = Vararg{pick_const_arg(𝕃, va, unwrapva(cache_va))}
         else
-            nprocessargs = length(cache_argtypes)
+            nprocessargs = ncache
             resize!(given_argtypes, nprocessargs)
         end
         for i = ngiven:nprocessargs
             given_argtypes[i] = va
         end
     elseif isvarargtype(cache_va)
-        nprocessargs = length(given_argtypes)
+        nprocessargs = ngiven
     else
-        @assert length(given_argtypes) == length(cache_argtypes)
-        nprocessargs = length(given_argtypes)
+        @assert ngiven == ncache
+        nprocessargs = ngiven
     end
     for i = 1:nprocessargs
         given_argtype = given_argtypes[i]
         cache_argtype = argtype_by_index(cache_argtypes, i)
-        given_argtype = pick_const_arg(𝕃, given_argtype, cache_argtype)
-        given_argtypes[i] = given_argtype
+        given_argtypes[i] = pick_const_arg(𝕃, given_argtype, cache_argtype)
     end
     return given_argtypes
 end
@@ -90,8 +90,9 @@ function is_argtype_match(𝕃::AbstractLattice,
 end
 
 function va_process_argtypes(𝕃::AbstractLattice, given_argtypes::Vector{Any}, nargs::UInt, isva::Bool)
+    nargs = Int(nargs)
     if isva || (!isempty(given_argtypes) && isvarargtype(given_argtypes[end]))
-        isva_given_argtypes = Vector{Any}(undef, Int(nargs))
+        isva_given_argtypes = Vector{Any}(undef, nargs)
         for i = 1:(nargs-isva)
             newarg = argtype_by_index(given_argtypes, i)
             if isva && has_conditional(𝕃) && isa(newarg, Conditional)
@@ -126,7 +127,7 @@ end
 function most_general_argtypes(method::Union{Method,Nothing}, @nospecialize(specTypes))
     mi_argtypes = Any[(unwrap_unionall(specTypes)::DataType).parameters...]
     nargtypes = length(mi_argtypes)
-    nargs = isa(method, Method) ? method.nargs : 0
+    nargs = isa(method, Method) ? Int(method.nargs) : 0
     if length(mi_argtypes) < nargs && isvarargtype(mi_argtypes[end])
         resize!(mi_argtypes, nargs)
     end
diff --git a/base/compiler/inferencestate.jl b/base/compiler/inferencestate.jl
index 75e947af6dac28..e26845b9da1f0b 100644
--- a/base/compiler/inferencestate.jl
+++ b/base/compiler/inferencestate.jl
@@ -853,7 +853,7 @@ function print_callstack(sv::InferenceState)
 end
 
 function narguments(sv::InferenceState, include_va::Bool=true)
-    nargs = sv.src.nargs
+    nargs = Int(sv.src.nargs)
     if !include_va
         nargs -= sv.src.isva
     end
diff --git a/base/compiler/optimize.jl b/base/compiler/optimize.jl
index 36b81147954109..ec206e47103ed3 100644
--- a/base/compiler/optimize.jl
+++ b/base/compiler/optimize.jl
@@ -1254,7 +1254,7 @@ function slot2reg(ir::IRCode, ci::CodeInfo, sv::OptimizationState)
     # need `ci` for the slot metadata, IR for the code
     svdef = sv.linfo.def
     @timeit "domtree 1" domtree = construct_domtree(ir)
-    defuse_insts = scan_slot_def_use(ci.nargs, ci, ir.stmts.stmt)
+    defuse_insts = scan_slot_def_use(Int(ci.nargs), ci, ir.stmts.stmt)
     𝕃ₒ = optimizer_lattice(sv.inlining.interp)
     @timeit "construct_ssa" ir = construct_ssa!(ci, ir, sv, domtree, defuse_insts, 𝕃ₒ) # consumes `ir`
     # NOTE now we have converted `ir` to the SSA form and eliminated slots
diff --git a/base/compiler/ssair/slot2ssa.jl b/base/compiler/ssair/slot2ssa.jl
index 1eedc09e015300..756dc98863af5b 100644
--- a/base/compiler/ssair/slot2ssa.jl
+++ b/base/compiler/ssair/slot2ssa.jl
@@ -33,7 +33,7 @@ function scan_entry!(result::Vector{SlotInfo}, idx::Int, @nospecialize(stmt))
     end
 end
 
-function scan_slot_def_use(nargs::Integer, ci::CodeInfo, code::Vector{Any})
+function scan_slot_def_use(nargs::Int, ci::CodeInfo, code::Vector{Any})
     nslots = length(ci.slotflags)
     result = SlotInfo[SlotInfo() for i = 1:nslots]
     # Set defs for arguments
diff --git a/base/compiler/typeinfer.jl b/base/compiler/typeinfer.jl
index ee3e93806f8531..d091fb8d2f5f8b 100644
--- a/base/compiler/typeinfer.jl
+++ b/base/compiler/typeinfer.jl
@@ -468,7 +468,7 @@ function adjust_effects(sv::InferenceState)
         # this frame is known to be safe
         ipo_effects = Effects(ipo_effects; nothrow=true)
     end
-    if is_inaccessiblemem_or_argmemonly(ipo_effects) && all(1:narguments(sv, #=include_va=#true)) do i::UInt
+    if is_inaccessiblemem_or_argmemonly(ipo_effects) && all(1:narguments(sv, #=include_va=#true)) do i::Int
             return is_mutation_free_argtype(sv.slottypes[i])
         end
         ipo_effects = Effects(ipo_effects; inaccessiblememonly=ALWAYS_TRUE)