diff --git a/base/compiler/ssair/EscapeAnalysis/EscapeAnalysis.jl b/base/compiler/ssair/EscapeAnalysis/EscapeAnalysis.jl
index 0ad55d6fbcd9e..a0abacb617085 100644
--- a/base/compiler/ssair/EscapeAnalysis/EscapeAnalysis.jl
+++ b/base/compiler/ssair/EscapeAnalysis/EscapeAnalysis.jl
@@ -24,10 +24,10 @@ using ._TOP_MOD:     # Base definitions
     isempty, ismutabletype, keys, last, length, max, min, missing, pop!, push!, pushfirst!,
     unwrap_unionall, !, !=, !==, &, *, +, -, :, <, <<, =>, >, |, ∈, ∉, ∩, ∪, ≠, ≤, ≥, ⊆
 using Core.Compiler: # Core.Compiler specific definitions
-    Bottom, IRCode, IR_FLAG_NOTHROW, InferenceResult, SimpleInferenceLattice,
+    AbstractLattice, Bottom, IRCode, IR_FLAG_NOTHROW, InferenceResult, SimpleInferenceLattice,
     argextype, fieldcount_noerror, hasintersect, has_flag, intrinsic_nothrow,
-    is_meta_expr_head, isbitstype, isexpr, println, setfield!_nothrow, singleton_type,
-    try_compute_field, try_compute_fieldidx, widenconst, ⊑, AbstractLattice
+    is_meta_expr_head, is_mutation_free_argtype, isexpr, println, setfield!_nothrow,
+    singleton_type, try_compute_field, try_compute_fieldidx, widenconst, ⊑
 
 include(x) = _TOP_MOD.include(@__MODULE__, x)
 if _TOP_MOD === Core.Compiler
@@ -859,7 +859,7 @@ function add_escape_change!(astate::AnalysisState, @nospecialize(x), xinfo::Esca
     xinfo === ⊥ && return nothing # performance optimization
     xidx = iridx(x, astate.estate)
     if xidx !== nothing
-        if force || !isbitstype(widenconst(argextype(x, astate.ir)))
+        if force || !is_mutation_free_argtype(argextype(x, astate.ir))
             push!(astate.changes, EscapeChange(xidx, xinfo))
         end
     end
@@ -869,7 +869,7 @@ end
 function add_liveness_change!(astate::AnalysisState, @nospecialize(x), livepc::Int)
     xidx = iridx(x, astate.estate)
     if xidx !== nothing
-        if !isbitstype(widenconst(argextype(x, astate.ir)))
+        if !is_mutation_free_argtype(argextype(x, astate.ir))
             push!(astate.changes, LivenessChange(xidx, livepc))
         end
     end
diff --git a/test/compiler/EscapeAnalysis/EscapeAnalysis.jl b/test/compiler/EscapeAnalysis/EscapeAnalysis.jl
index 99bd86228f50a..9afe49c01562d 100644
--- a/test/compiler/EscapeAnalysis/EscapeAnalysis.jl
+++ b/test/compiler/EscapeAnalysis/EscapeAnalysis.jl
@@ -290,7 +290,7 @@ end
 
     let # typeassert
         result = code_escapes((Any,)) do x
-            y = x::String
+            y = x::Base.RefValue{Any}
             return y
         end
         r = only(findall(isreturn, result.ir.stmts.stmt))
@@ -305,11 +305,6 @@ end
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r)
         @test !has_all_escape(result.state[Argument(2)])
-
-        result = code_escapes((Module,)) do m
-            isdefined(m, 10) # throws
-        end
-        @test has_thrown_escape(result.state[Argument(2)])
     end
 end
 
@@ -685,8 +680,8 @@ end
         @test has_all_escape(result.state[Argument(2)])
     end
     let result = @eval EATModule() begin
-            const Rx = SafeRef{String}("Rx")
-            $code_escapes((String,)) do s
+            const Rx = SafeRef{Any}(nothing)
+            $code_escapes((Base.RefValue{String},)) do s
                 setfield!(Rx, :x, s)
                 Core.sizeof(Rx[])
             end
@@ -712,7 +707,7 @@ end
     # ------------
 
     # field escape should propagate to :new arguments
-    let result = code_escapes((String,)) do a
+    let result = code_escapes((Base.RefValue{String},)) do a
             o = SafeRef(a)
             Core.donotdelete(o)
             return o[]
@@ -722,7 +717,7 @@ end
         @test has_return_escape(result.state[Argument(2)], r)
         @test is_load_forwardable(result.state[SSAValue(i)])
     end
-    let result = code_escapes((String,)) do a
+    let result = code_escapes((Base.RefValue{String},)) do a
             t = SafeRef((a,))
             f = t[][1]
             return f
@@ -731,9 +726,8 @@ end
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r)
         @test is_load_forwardable(result.state[SSAValue(i)])
-        result.state[SSAValue(i)].AliasInfo
     end
-    let result = code_escapes((String, String)) do a, b
+    let result = code_escapes((Base.RefValue{String}, Base.RefValue{String})) do a, b
             obj = SafeRefs(a, b)
             Core.donotdelete(obj)
             fld1 = obj[1]
@@ -748,31 +742,31 @@ end
     end
 
     # field escape should propagate to `setfield!` argument
-    let result = code_escapes((String,)) do a
-            o = SafeRef("foo")
+    let result = code_escapes((Base.RefValue{String},)) do a
+            o = SafeRef(Ref("foo"))
             Core.donotdelete(o)
             o[] = a
             return o[]
         end
-        i = only(findall(isnew, result.ir.stmts.stmt))
+        i = last(findall(isnew, result.ir.stmts.stmt))
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r)
         @test is_load_forwardable(result.state[SSAValue(i)])
     end
     # propagate escape information imposed on return value of `setfield!` call
-    let result = code_escapes((String,)) do a
-            obj = SafeRef("foo")
+    let result = code_escapes((Base.RefValue{String},)) do a
+            obj = SafeRef(Ref("foo"))
             Core.donotdelete(obj)
             return (obj[] = a)
         end
-        i = only(findall(isnew, result.ir.stmts.stmt))
+        i = last(findall(isnew, result.ir.stmts.stmt))
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r)
         @test is_load_forwardable(result.state[SSAValue(i)])
     end
 
     # nested allocations
-    let result = code_escapes((String,)) do a
+    let result = code_escapes((Base.RefValue{String},)) do a
             o1 = SafeRef(a)
             o2 = SafeRef(o1)
             return o2[]
@@ -787,7 +781,7 @@ end
             end
         end
     end
-    let result = code_escapes((String,)) do a
+    let result = code_escapes((Base.RefValue{String},)) do a
             o1 = (a,)
             o2 = (o1,)
             return o2[1]
@@ -802,7 +796,7 @@ end
             end
         end
     end
-    let result = code_escapes((String,)) do a
+    let result = code_escapes((Base.RefValue{String},)) do a
             o1  = SafeRef(a)
             o2  = SafeRef(o1)
             o1′ = o2[]
@@ -844,7 +838,7 @@ end
             @test has_return_escape(result.state[SSAValue(i)], r)
         end
     end
-    let result = code_escapes((String,)) do x
+    let result = code_escapes((Base.RefValue{String},)) do x
             o = Ref(x)
             Core.donotdelete(o)
             broadcast(identity, o)
@@ -892,7 +886,7 @@ end
         end
     end
     # when ϕ-node merges values with different types
-    let result = code_escapes((Bool,String,String,String)) do cond, x, y, z
+    let result = code_escapes((Bool,Base.RefValue{String},Base.RefValue{String},Base.RefValue{String})) do cond, x, y, z
             local out
             if cond
                 ϕ = SafeRef(x)
@@ -904,7 +898,7 @@ end
         end
         r = only(findall(isreturn, result.ir.stmts.stmt))
         t = only(findall(iscall((result.ir, throw)), result.ir.stmts.stmt))
-        ϕ = only(findall(==(Union{SafeRef{String},SafeRefs{String,String}}), result.ir.stmts.type))
+        ϕ = only(findall(==(Union{SafeRef{Base.RefValue{String}},SafeRefs{Base.RefValue{String},Base.RefValue{String}}}), result.ir.stmts.type))
         @test has_return_escape(result.state[Argument(3)], r) # x
         @test !has_return_escape(result.state[Argument(4)], r) # y
         @test has_return_escape(result.state[Argument(5)], r) # z
@@ -1038,7 +1032,7 @@ end
     end
     # alias via typeassert
     let result = code_escapes((Any,)) do a
-            r = a::String
+            r = a::Base.RefValue{String}
             return r
         end
         r = only(findall(isreturn, result.ir.stmts.stmt))
@@ -1077,11 +1071,11 @@ end
         @test has_all_escape(result.state[Argument(3)]) # a
     end
     # alias via ϕ-node
-    let result = code_escapes((Bool,String)) do cond, x
+    let result = code_escapes((Bool,Base.RefValue{String})) do cond, x
             if cond
-                ϕ2 = ϕ1 = SafeRef("foo")
+                ϕ2 = ϕ1 = SafeRef(Ref("foo"))
             else
-                ϕ2 = ϕ1 = SafeRef("bar")
+                ϕ2 = ϕ1 = SafeRef(Ref("bar"))
             end
             ϕ2[] = x
             return ϕ1[]
@@ -1094,14 +1088,16 @@ end
             @test is_load_forwardable(result.state[SSAValue(i)])
         end
         for i in findall(isnew, result.ir.stmts.stmt)
-            @test is_load_forwardable(result.state[SSAValue(i)])
+            if result.ir[SSAValue(i)][:type] <: SafeRef
+                @test is_load_forwardable(result.state[SSAValue(i)])
+            end
         end
     end
-    let result = code_escapes((Bool,Bool,String)) do cond1, cond2, x
+    let result = code_escapes((Bool,Bool,Base.RefValue{String})) do cond1, cond2, x
             if cond1
-                ϕ2 = ϕ1 = SafeRef("foo")
+                ϕ2 = ϕ1 = SafeRef(Ref("foo"))
             else
-                ϕ2 = ϕ1 = SafeRef("bar")
+                ϕ2 = ϕ1 = SafeRef(Ref("bar"))
             end
             cond2 && (ϕ2[] = x)
             return ϕ1[]
@@ -1114,12 +1110,14 @@ end
             @test is_load_forwardable(result.state[SSAValue(i)])
         end
         for i in findall(isnew, result.ir.stmts.stmt)
-            @test is_load_forwardable(result.state[SSAValue(i)])
+            if result.ir[SSAValue(i)][:type] <: SafeRef
+                @test is_load_forwardable(result.state[SSAValue(i)])
+            end
         end
     end
     # alias via π-node
     let result = code_escapes((Any,)) do x
-            if isa(x, String)
+            if isa(x, Base.RefValue{String})
                 return x
             end
             throw("error!")
@@ -1213,7 +1211,7 @@ end
 
     # conservatively handle unknown field:
     # all fields should be escaped, but the allocation itself doesn't need to be escaped
-    let result = code_escapes((String, Symbol)) do a, fld
+    let result = code_escapes((Base.RefValue{String}, Symbol)) do a, fld
             obj = SafeRef(a)
             return getfield(obj, fld)
         end
@@ -1222,7 +1220,7 @@ end
         @test has_return_escape(result.state[Argument(2)], r) # a
         @test !is_load_forwardable(result.state[SSAValue(i)]) # obj
     end
-    let result = code_escapes((String, String, Symbol)) do a, b, fld
+    let result = code_escapes((Base.RefValue{String}, Base.RefValue{String}, Symbol)) do a, b, fld
             obj = SafeRefs(a, b)
             return getfield(obj, fld) # should escape both `a` and `b`
         end
@@ -1232,7 +1230,7 @@ end
         @test has_return_escape(result.state[Argument(3)], r) # b
         @test !is_load_forwardable(result.state[SSAValue(i)]) # obj
     end
-    let result = code_escapes((String, String, Int)) do a, b, idx
+    let result = code_escapes((Base.RefValue{String}, Base.RefValue{String}, Int)) do a, b, idx
             obj = SafeRefs(a, b)
             return obj[idx] # should escape both `a` and `b`
         end
@@ -1242,33 +1240,33 @@ end
         @test has_return_escape(result.state[Argument(3)], r) # b
         @test !is_load_forwardable(result.state[SSAValue(i)]) # obj
     end
-    let result = code_escapes((String, String, Symbol)) do a, b, fld
-            obj = SafeRefs("a", "b")
+    let result = code_escapes((Base.RefValue{String}, Base.RefValue{String}, Symbol)) do a, b, fld
+            obj = SafeRefs(Ref("a"), Ref("b"))
             setfield!(obj, fld, a)
             return obj[2] # should escape `a`
         end
-        i = only(findall(isnew, result.ir.stmts.stmt))
+        i = last(findall(isnew, result.ir.stmts.stmt))
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r) # a
         @test !has_return_escape(result.state[Argument(3)], r) # b
         @test !is_load_forwardable(result.state[SSAValue(i)]) # obj
     end
-    let result = code_escapes((String, Symbol)) do a, fld
-            obj = SafeRefs("a", "b")
+    let result = code_escapes((Base.RefValue{String}, Symbol)) do a, fld
+            obj = SafeRefs(Ref("a"), Ref("b"))
             setfield!(obj, fld, a)
             return obj[1] # this should escape `a`
         end
-        i = only(findall(isnew, result.ir.stmts.stmt))
+        i = last(findall(isnew, result.ir.stmts.stmt))
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r) # a
         @test !is_load_forwardable(result.state[SSAValue(i)]) # obj
     end
-    let result = code_escapes((String, String, Int)) do a, b, idx
-            obj = SafeRefs("a", "b")
+    let result = code_escapes((Base.RefValue{String}, Base.RefValue{String}, Int)) do a, b, idx
+        obj = SafeRefs(Ref("a"), Ref("b"))
             obj[idx] = a
             return obj[2] # should escape `a`
         end
-        i = only(findall(isnew, result.ir.stmts.stmt))
+        i = last(findall(isnew, result.ir.stmts.stmt))
         r = only(findall(isreturn, result.ir.stmts.stmt))
         @test has_return_escape(result.state[Argument(2)], r) # a
         @test !has_return_escape(result.state[Argument(3)], r) # b
@@ -1280,7 +1278,7 @@ end
 
     let result = @eval EATModule() begin
             @noinline getx(obj) = obj[]
-            $code_escapes((String,)) do a
+            $code_escapes((Base.RefValue{String},)) do a
                 obj = SafeRef(a)
                 fld = getx(obj)
                 return fld
@@ -1294,8 +1292,8 @@ end
     end
 
     # TODO interprocedural alias analysis
-    let result = code_escapes((SafeRef{String},)) do s
-            s[] = "bar"
+    let result = code_escapes((SafeRef{Base.RefValue{String}},)) do s
+            s[] = Ref("bar")
             global GV = s[]
             nothing
         end
@@ -1335,7 +1333,7 @@ end
     let result = @eval EATModule() begin
             @noinline mysetindex!(x, a) = x[1] = a
             const Ax = Vector{Any}(undef, 1)
-            $code_escapes((String,)) do s
+            $code_escapes((Base.RefValue{String},)) do s
                 mysetindex!(Ax, s)
             end
         end
@@ -1391,11 +1389,11 @@ end
     end
 
     # handle conflicting field information correctly
-    let result = code_escapes((Bool,String,String,)) do cnd, baz, qux
+    let result = code_escapes((Bool,Base.RefValue{String},Base.RefValue{String},)) do cnd, baz, qux
             if cnd
-                o = SafeRef("foo")
+                o = SafeRef(Ref("foo"))
             else
-                o = SafeRefs("bar", baz)
+                o = SafeRefs(Ref("bar"), baz)
                 r = getfield(o, 2)
             end
             if cnd
@@ -1409,12 +1407,14 @@ end
         @test has_return_escape(result.state[Argument(3)], r) # baz
         @test has_return_escape(result.state[Argument(4)], r) # qux
         for new in findall(isnew, result.ir.stmts.stmt)
-            @test is_load_forwardable(result.state[SSAValue(new)])
+            if !(result.ir[SSAValue(new)][:type] <: Base.RefValue)
+                @test is_load_forwardable(result.state[SSAValue(new)])
+            end
         end
     end
-    let result = code_escapes((Bool,String,String,)) do cnd, baz, qux
+    let result = code_escapes((Bool,Base.RefValue{String},Base.RefValue{String},)) do cnd, baz, qux
             if cnd
-                o = SafeRefs("foo", "bar")
+                o = SafeRefs(Ref("foo"), Ref("bar"))
                 r = setfield!(o, 2, baz)
             else
                 o = SafeRef(qux)
@@ -2141,9 +2141,9 @@ end
 # propagate escapes imposed on call arguments
 @noinline broadcast_noescape2(b) = broadcast(identity, b)
 let result = code_escapes() do
-        broadcast_noescape2(Ref("Hi"))
+        broadcast_noescape2(Ref(Ref("Hi")))
     end
-    i = only(findall(isnew, result.ir.stmts.stmt))
+    i = last(findall(isnew, result.ir.stmts.stmt))
     @test_broken !has_return_escape(result.state[SSAValue(i)]) # TODO interprocedural alias analysis
     @test !has_thrown_escape(result.state[SSAValue(i)])
 end