diff --git a/src/Bridges/Bridges.jl b/src/Bridges/Bridges.jl
index ccfe3bd869..8251eb0d32 100644
--- a/src/Bridges/Bridges.jl
+++ b/src/Bridges/Bridges.jl
@@ -302,13 +302,13 @@ function runtests(
     end
     # Test other bridge functions
     for b in values(Constraint.bridges(model))
-        _general_bridge_tests(b)
+        _general_bridge_tests(something(b))
     end
     for b in values(Objective.bridges(model))
-        _general_bridge_tests(b)
+        _general_bridge_tests(something(b))
     end
     for b in values(Variable.bridges(model))
-        _general_bridge_tests(b)
+        _general_bridge_tests(something(b))
     end
     _test_delete(Bridge, model, inner)
     return
diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 7e664cc5b9..014c4847b3 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -71,7 +71,7 @@ function Base.empty!(map::Map)
         map.unbridged_function =
             Dict{MOI.VariableIndex,Tuple{Int64,MOI.AbstractScalarFunction}}()
     else
-        empty!(map.unbridged_function)
+        empty!(something(map.unbridged_function))
     end
     empty!(map.parent_index)
     map.current_context = 0
@@ -371,13 +371,14 @@ function add_keys_for_bridge(
         MOI.VariableIndex(-(bridge_index - 1 + i)) for i in 1:MOI.dimension(set)
     ]
     if map.unbridged_function !== nothing
-        mappings = unbridged_map(map.bridges[bridge_index], variables)
+        mappings =
+            unbridged_map(something(map.bridges[bridge_index]), variables)
         if mappings === nothing
             map.unbridged_function = nothing
         else
             for mapping in mappings
                 push!(
-                    map.unbridged_function,
+                    something(map.unbridged_function),
                     mapping.first => (bridge_index, mapping.second),
                 )
             end
@@ -441,7 +442,7 @@ Return the expression of `vi` in terms of bridged variables.
 """
 function unbridged_function(map::Map, vi::MOI.VariableIndex)
     throw_if_cannot_unbridge(map)
-    context_func = get(map.unbridged_function, vi, nothing)
+    context_func = get(something(map.unbridged_function), vi, nothing)
     if context_func === nothing
         return nothing
     end
diff --git a/src/FileFormats/CBF/CBF.jl b/src/FileFormats/CBF/CBF.jl
index 3bd110f840..d1895d5d28 100644
--- a/src/FileFormats/CBF/CBF.jl
+++ b/src/FileFormats/CBF/CBF.jl
@@ -59,7 +59,7 @@ end
 
 Create an empty instance of `FileFormats.CBF.Model`.
 """
-Model() = Model{Float64}()
+Model(; kwargs...) = Model{Float64}()
 
 Base.show(io::IO, ::Model) = print(io, "A Conic Benchmark Format (CBF) model")
 
diff --git a/src/FileFormats/MPS/MPS.jl b/src/FileFormats/MPS/MPS.jl
index 34ce4b941f..5bea825d7e 100644
--- a/src/FileFormats/MPS/MPS.jl
+++ b/src/FileFormats/MPS/MPS.jl
@@ -1319,7 +1319,7 @@ function parse_name_line(data::TempMPSModel, line::String)
     if m === nothing
         error("Malformed NAME line: ", line)
     end
-    data.name = strip(m[1])
+    data.name = strip(m[1]::AbstractString)
     return
 end
 
diff --git a/src/FileFormats/NL/NL.jl b/src/FileFormats/NL/NL.jl
index b22bb8f539..cc0fa0e211 100644
--- a/src/FileFormats/NL/NL.jl
+++ b/src/FileFormats/NL/NL.jl
@@ -781,11 +781,11 @@ function _assert_has_model(::Nothing, attr)
     )
 end
 
-_assert_has_model(::MOI.Utilities.UniversalFallback, ::Any) = nothing
+_assert_has_model(model::MOI.Utilities.UniversalFallback, ::Any) = model
 
 function MOI.get(model::Model, attr::MOI.AbstractModelAttribute)
-    _assert_has_model(model.model, attr)
-    return MOI.get(model.model, attr)
+    inner = _assert_has_model(model.model, attr)
+    return MOI.get(inner, attr)
 end
 
 function MOI.get(
@@ -793,8 +793,8 @@ function MOI.get(
     attr::MOI.AbstractConstraintAttribute,
     ci::MOI.ConstraintIndex,
 )
-    _assert_has_model(model.model, attr)
-    return MOI.get(model.model, attr, ci)
+    inner = _assert_has_model(model.model, attr)
+    return MOI.get(inner, attr, ci)
 end
 
 function MOI.get(
@@ -802,8 +802,8 @@ function MOI.get(
     attr::MOI.AbstractVariableAttribute,
     x::MOI.VariableIndex,
 )
-    _assert_has_model(model.model, attr)
-    return MOI.get(model.model, attr, x)
+    inner = _assert_has_model(model.model, attr)
+    return MOI.get(inner, attr, x)
 end
 
 end
diff --git a/src/FileFormats/SDPA/SDPA.jl b/src/FileFormats/SDPA/SDPA.jl
index f3f0b4837f..8599013bf5 100644
--- a/src/FileFormats/SDPA/SDPA.jl
+++ b/src/FileFormats/SDPA/SDPA.jl
@@ -302,20 +302,17 @@ function _dim_to_set(s::AbstractString)
         return MOI.Nonnegatives(-block_dim)
     end
 end
-function _parse_dimensions(dims)
+function _parse_dimensions(dims::AbstractString)
     isvalid(char) = isdigit(char) || char == '-'
+    is_delimiter(char) = isspace(char) || char == ','
     start = findfirst(isvalid, dims)
-    stop = findlast(isvalid, dims)
-    if isnothing(start)
+    if start === nothing
         return Union{MOI.PositiveSemidefiniteConeTriangle,MOI.Nonnegatives}[]
     end
-    function is_delimiter(char)
-        return isspace(char) || char == ','
-    end
+    stop = findlast(isvalid, dims)::Int
     s = split(dims[start:stop], is_delimiter)
-    s = filter(!isempty, s)
     return Union{MOI.PositiveSemidefiniteConeTriangle,MOI.Nonnegatives}[
-        _dim_to_set(dim) for dim in s
+        _dim_to_set(dim) for dim in filter!(!isempty, s)
     ]
 end
 
@@ -324,19 +321,20 @@ end
 
 Read `io` in the SDPA file format and store the result in `model`.
 """
-function Base.read!(io::IO, model::Model{T}) where {T}
+function Base.read!(io::IO, model::Model{T}) where {T<:Real}
     if !MOI.is_empty(model)
         error("Cannot read in file because model is not empty.")
     end
     num_variables_read = false
     num_blocks = nothing
-    block_sets = nothing
+    block_sets = Union{MOI.PositiveSemidefiniteConeTriangle,MOI.Nonnegatives}[]
+    block_sets_read = false
     objective_read = false
     integer_read = false
-    scalar_vars = nothing
+    scalar_vars = MOI.VariableIndex[]
     intvar_idx = Int[]
     c = nothing
-    funcs = nothing
+    funcs = MOI.VectorAffineFunction{T}[]
     MOI.set(model, MOI.ObjectiveSense(), MOI.MIN_SENSE)
     while !eof(io)
         line = strip(readline(io))
@@ -375,22 +373,26 @@ function Base.read!(io::IO, model::Model{T}) where {T}
             # According to http://plato.asu.edu/ftp/sdpa_format.txt,
             # additional text after the number of blocks should be ignored.
             num_blocks = parse(Int, split(line)[1])
-        elseif block_sets === nothing
+        elseif !block_sets_read
             if isempty(line) && !iszero(num_blocks)
                 continue
             end
             block_sets = _parse_dimensions(line)
+            block_sets_read = true
             if length(block_sets) != num_blocks
                 error(
                     "The number of blocks ($num_blocks) does not match the length of the list of blocks dimensions ($(length(block_sets))).",
                 )
             end
-            funcs = [
-                MOI.VectorAffineFunction(
-                    MOI.VectorAffineTerm{T}[],
-                    zeros(T, MOI.dimension(block_sets[i])),
-                ) for i in 1:num_blocks
-            ]
+            for i in 1:num_blocks
+                push!(
+                    funcs,
+                    MOI.VectorAffineFunction(
+                        MOI.VectorAffineTerm{T}[],
+                        zeros(T, MOI.dimension(block_sets[i])),
+                    ),
+                )
+            end
         elseif !objective_read
             num_vars = MOI.get(model, MOI.NumberOfVariables())
             if isempty(line) && !iszero(num_vars)
@@ -452,7 +454,7 @@ function Base.read!(io::IO, model::Model{T}) where {T}
             end
         end
     end
-    for block in 1:num_blocks
+    for block in 1:(num_blocks::Int)
         MOI.add_constraint(model, funcs[block], block_sets[block])
     end
     for var_idx in intvar_idx
diff --git a/src/Nonlinear/evaluator.jl b/src/Nonlinear/evaluator.jl
index 21955c14d1..2414ac7db1 100644
--- a/src/Nonlinear/evaluator.jl
+++ b/src/Nonlinear/evaluator.jl
@@ -90,7 +90,7 @@ function MOI.objective_expr(evaluator::Evaluator)
     end
     return convert_to_expr(
         evaluator,
-        evaluator.model.objective;
+        something(evaluator.model.objective);
         moi_output_format = true,
     )
 end
diff --git a/src/Nonlinear/operators.jl b/src/Nonlinear/operators.jl
index ee49768111..d318fdb241 100644
--- a/src/Nonlinear/operators.jl
+++ b/src/Nonlinear/operators.jl
@@ -575,7 +575,7 @@ function eval_univariate_hessian(
 ) where {T}
     id = registry.univariate_operator_to_id[op]
     if id <= registry.univariate_user_operator_start
-        return _eval_univariate_2nd_deriv(id, x)
+        return _eval_univariate_2nd_deriv(id, x)::T
     end
     offset = id - registry.univariate_user_operator_start
     operator = registry.registered_univariate_operators[offset]
diff --git a/src/Utilities/objective_container.jl b/src/Utilities/objective_container.jl
index 2dafc71974..30fa031c52 100644
--- a/src/Utilities/objective_container.jl
+++ b/src/Utilities/objective_container.jl
@@ -121,21 +121,21 @@ function MOI.get(
     ::MOI.ObjectiveFunction{F},
 ) where {T,F}
     if o.scalar_affine !== nothing
-        return convert(F, o.scalar_affine)
+        return convert(F, something(o.scalar_affine))
     elseif o.single_variable !== nothing
-        return convert(F, o.single_variable)
+        return convert(F, something(o.single_variable))
     elseif o.scalar_quadratic !== nothing
-        return convert(F, o.scalar_quadratic)
+        return convert(F, something(o.scalar_quadratic))
     elseif o.scalar_nonlinear !== nothing
-        return convert(F, o.scalar_nonlinear)
+        return convert(F, something(o.scalar_nonlinear))
     elseif o.vector_variables !== nothing
-        return convert(F, o.vector_variables)
+        return convert(F, something(o.vector_variables))
     elseif o.vector_affine !== nothing
-        return convert(F, o.vector_affine)
+        return convert(F, something(o.vector_affine))
     elseif o.vector_quadratic !== nothing
-        return convert(F, o.vector_quadratic)
+        return convert(F, something(o.vector_quadratic))
     elseif o.vector_nonlinear !== nothing
-        return convert(F, o.vector_nonlinear)
+        return convert(F, something(o.vector_nonlinear))
     end
     # The default if no objective is set.
     return convert(F, zero(MOI.ScalarAffineFunction{T}))
@@ -262,11 +262,13 @@ function MOI.modify(
     change::MOI.AbstractFunctionModification,
 ) where {T}
     if o.single_variable !== nothing
-        o.single_variable = modify_function!(o.single_variable, change)
+        o.single_variable =
+            modify_function!(something(o.single_variable), change)
     elseif o.scalar_affine !== nothing
-        o.scalar_affine = modify_function!(o.scalar_affine, change)
+        o.scalar_affine = modify_function!(something(o.scalar_affine), change)
     elseif o.scalar_quadratic !== nothing
-        o.scalar_quadratic = modify_function!(o.scalar_quadratic, change)
+        o.scalar_quadratic =
+            modify_function!(something(o.scalar_quadratic), change)
     elseif o.scalar_nonlinear !== nothing
         throw(
             MOI.ModifyObjectiveNotAllowed(
@@ -276,11 +278,13 @@ function MOI.modify(
             ),
         )
     elseif o.vector_variables !== nothing
-        o.vector_variables = modify_function!(o.vector_variables, change)
+        o.vector_variables =
+            modify_function!(something(o.vector_variables), change)
     elseif o.vector_quadratic !== nothing
-        o.vector_quadratic = modify_function!(o.vector_quadratic, change)
+        o.vector_quadratic =
+            modify_function!(something(o.vector_quadratic), change)
     elseif o.vector_affine !== nothing
-        o.vector_affine = modify_function!(o.vector_affine, change)
+        o.vector_affine = modify_function!(something(o.vector_affine), change)
     elseif o.vector_nonlinear !== nothing
         throw(
             MOI.ModifyObjectiveNotAllowed(
@@ -304,13 +308,13 @@ end
 
 function MOI.delete(o::ObjectiveContainer, x::MOI.VariableIndex)
     if o.single_variable !== nothing
-        if x == o.single_variable
+        if x == something(o.single_variable)
             _empty_keeping_sense(o)
         end
     elseif o.scalar_affine !== nothing
-        o.scalar_affine = remove_variable(o.scalar_affine, x)
+        o.scalar_affine = remove_variable(something(o.scalar_affine), x)
     elseif o.scalar_quadratic !== nothing
-        o.scalar_quadratic = remove_variable(o.scalar_quadratic, x)
+        o.scalar_quadratic = remove_variable(something(o.scalar_quadratic), x)
     elseif o.scalar_nonlinear !== nothing
         throw(
             MOI.DeleteNotAllowed(
@@ -320,14 +324,14 @@ function MOI.delete(o::ObjectiveContainer, x::MOI.VariableIndex)
             ),
         )
     elseif o.vector_variables !== nothing
-        o.vector_variables = remove_variable(o.vector_variables, x)
-        if isempty(o.vector_variables.variables)
+        o.vector_variables = remove_variable(something(o.vector_variables), x)
+        if isempty(something(o.vector_variables).variables)
             _empty_keeping_sense(o)
         end
     elseif o.vector_affine !== nothing
-        o.vector_affine = remove_variable(o.vector_affine, x)
+        o.vector_affine = remove_variable(something(o.vector_affine), x)
     elseif o.vector_quadratic !== nothing
-        o.vector_quadratic = remove_variable(o.vector_quadratic, x)
+        o.vector_quadratic = remove_variable(something(o.vector_quadratic), x)
     elseif o.vector_nonlinear !== nothing
         throw(
             MOI.DeleteNotAllowed(
@@ -343,13 +347,14 @@ end
 function MOI.delete(o::ObjectiveContainer, x::Vector{MOI.VariableIndex})
     keep = v -> !(v in x)
     if o.single_variable !== nothing
-        if o.single_variable in x
+        if something(o.single_variable) in x
             _empty_keeping_sense(o)
         end
     elseif o.scalar_affine !== nothing
-        o.scalar_affine = filter_variables(keep, o.scalar_affine)
+        o.scalar_affine = filter_variables(keep, something(o.scalar_affine))
     elseif o.scalar_quadratic !== nothing
-        o.scalar_quadratic = filter_variables(keep, o.scalar_quadratic)
+        o.scalar_quadratic =
+            filter_variables(keep, something(o.scalar_quadratic))
     elseif o.scalar_nonlinear !== nothing
         throw(
             MOI.DeleteNotAllowed(
@@ -359,14 +364,16 @@ function MOI.delete(o::ObjectiveContainer, x::Vector{MOI.VariableIndex})
             ),
         )
     elseif o.vector_variables !== nothing
-        o.vector_variables = filter_variables(keep, o.vector_variables)
-        if isempty(o.vector_variables.variables)
+        o.vector_variables =
+            filter_variables(keep, something(o.vector_variables))
+        if isempty(something(o.vector_variables).variables)
             _empty_keeping_sense(o)
         end
     elseif o.vector_affine !== nothing
-        o.vector_affine = filter_variables(keep, o.vector_affine)
+        o.vector_affine = filter_variables(keep, something(o.vector_affine))
     elseif o.vector_quadratic !== nothing
-        o.vector_quadratic = filter_variables(keep, o.vector_quadratic)
+        o.vector_quadratic =
+            filter_variables(keep, something(o.vector_quadratic))
     elseif o.vector_nonlinear !== nothing
         throw(
             MOI.DeleteNotAllowed(
diff --git a/src/Utilities/universalfallback.jl b/src/Utilities/universalfallback.jl
index 21842f53a5..c57df71d7b 100644
--- a/src/Utilities/universalfallback.jl
+++ b/src/Utilities/universalfallback.jl
@@ -280,7 +280,7 @@ function MOI.delete(uf::UniversalFallback, vi::MOI.VariableIndex)
         delete!(d, vi)
     end
     if uf.objective !== nothing
-        uf.objective = remove_variable(uf.objective, vi)
+        uf.objective = remove_variable(something(uf.objective), vi)
     end
     for constraints in values(uf.single_variable_constraints)
         _remove_variable(uf, constraints, vi)
@@ -309,7 +309,7 @@ function MOI.delete(uf::UniversalFallback, vis::Vector{MOI.VariableIndex})
         end
     end
     if uf.objective !== nothing
-        uf.objective = remove_variable(uf.objective, vis)
+        uf.objective = remove_variable(something(uf.objective), vis)
     end
     for constraints in values(uf.single_variable_constraints)
         for vi in vis
@@ -678,7 +678,7 @@ function MOI.get(
         # to check for duplicate names.
         MOI.get(uf.model, MOI.ConstraintIndex, name)
     end
-    ci_uf = get(uf.name_to_con, name, nothing)
+    ci_uf = get(something(uf.name_to_con), name, nothing)
     throw_if_multiple_with_name(ci_uf, name)
     c = check_type_and_multiple_names(MOI.ConstraintIndex{F,S}, ci_uf, ci, name)
     return c
@@ -692,7 +692,7 @@ function MOI.get(
     if uf.name_to_con === nothing
         uf.name_to_con = build_name_to_con_map(uf.con_to_name)
     end
-    ci_uf = get(uf.name_to_con, name, nothing)
+    ci_uf = get(something(uf.name_to_con), name, nothing)
     throw_if_multiple_with_name(ci_uf, name)
     return check_type_and_multiple_names(
         MOI.ConstraintIndex,