diff --git a/base/compiler/ssair/passes.jl b/base/compiler/ssair/passes.jl
index 7bf1b70487087..4bfb5f3fcde56 100644
--- a/base/compiler/ssair/passes.jl
+++ b/base/compiler/ssair/passes.jl
@@ -1265,6 +1265,7 @@ function sroa_mutables!(ir::IRCode, defuses::IdDict{Int, Tuple{SPCSet, SSADefUse
         typ = unwrap_unionall(ir.stmts[newidx][:type])
         # Could still end up here if we tried to setfield! on an immutable, which would
         # error at runtime, but is not illegal to have in the IR.
+        typ = widenconst(typ)
         ismutabletype(typ) || continue
         typ = typ::DataType
         # First check for any finalizer calls
diff --git a/test/compiler/irpasses.jl b/test/compiler/irpasses.jl
index 43371b51f6a64..c704a8cf1c434 100644
--- a/test/compiler/irpasses.jl
+++ b/test/compiler/irpasses.jl
@@ -1230,3 +1230,18 @@ let src = code_typed1(named_tuple_elim, Tuple{Symbol, Tuple})
           count(iscall((src, Core._svec_ref)), src.code) == 0 &&
           count(iscall(x->!isa(argextype(x, src).val, Core.Builtin)), src.code) == 0
 end
+
+# Test that sroa works if the struct type is a PartialStruct
+mutable struct OneConstField
+    const a::Int
+    b::Int
+end
+
+@eval function one_const_field_partial()
+    # Use explicit :new here to avoid inlining messing with the type
+    strct = $(Expr(:new, OneConstField, 1, 2))
+    strct.b = 4
+    strct.b = 5
+    return strct.b
+end
+@test fully_eliminated(one_const_field_partial; retval=5)