From 86b0432350276da2626b9e9771f8b7db7baa8040 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Fri, 10 Jan 2020 13:42:34 +0100
Subject: [PATCH 1/7] remove N field

---
 src/Utilities/mockoptimizer.jl |  4 +--
 src/attributes.jl              | 54 ++++++++++++++++------------------
 src/nlp.jl                     | 10 +++----
 3 files changed, 33 insertions(+), 35 deletions(-)

diff --git a/src/Utilities/mockoptimizer.jl b/src/Utilities/mockoptimizer.jl
index cf7246af3c..56c0f950d1 100644
--- a/src/Utilities/mockoptimizer.jl
+++ b/src/Utilities/mockoptimizer.jl
@@ -307,14 +307,14 @@ function MOI.get(mock::MockOptimizer, attr::MOI.DualObjectiveValue)
     end
 end
 function MOI.get(mock::MockOptimizer, attr::MOI.PrimalStatus)
-    if attr.N > mock.result_count
+    if attr.result_index > mock.result_count
         return MOI.NO_SOLUTION
     else
         return mock.primalstatus
     end
 end
 function MOI.get(mock::MockOptimizer, attr::MOI.DualStatus)
-    if attr.N > mock.result_count
+    if attr.result_index > mock.result_count
         return MOI.NO_SOLUTION
     else
         return mock.dualstatus
diff --git a/src/attributes.jl b/src/attributes.jl
index 7604eb1446..15e4fee745 100644
--- a/src/attributes.jl
+++ b/src/attributes.jl
@@ -123,13 +123,11 @@ struct ResultIndexBoundsError{AttrType} <: Exception
     attr::AttrType
     result_count::Int
 end
-# TODO: rename the .N -> .result_index field in necessary attributes (e.g.,
-# VariablePrimal, ConstraintPrimal, ConstraintDual), and remove this helper
-# function.
+
 _result_index_field(attr) = attr.result_index
 function check_result_index_bounds(model::ModelLike, attr)
     result_count = get(model, ResultCount())
-    if !(1 <= _result_index_field(attr) <= result_count)
+    if !(1 <= attr.result_index <= result_count)
         throw(ResultIndexBoundsError(attr, result_count))
     end
 end
@@ -946,10 +944,10 @@ A variable attribute for the assignment to some primal variable's value in resul
 If `N` is omitted, it is 1 by default.
 """
 struct VariablePrimal <: AbstractVariableAttribute
-    N::Int
+    result_index::Int
 end
 VariablePrimal() = VariablePrimal(1)
-_result_index_field(attr::VariablePrimal) = attr.N
+_result_index_field(attr::VariablePrimal) = attr.result_index
 
 """
     CallbackVariablePrimal(callback_data)
@@ -1025,11 +1023,11 @@ A constraint attribute for the initial assignment to some constraint's dual valu
 struct ConstraintDualStart <: AbstractConstraintAttribute end
 
 """
-    ConstraintPrimal(N)
+    ConstraintPrimal(result_index::Int)
     ConstraintPrimal()
 
-A constraint attribute for the assignment to some constraint's primal value(s) in result `N`.
-If `N` is omitted, it is 1 by default.
+A constraint attribute for the assignment to some constraint's primal value(s)
+in result `result_index`. If `result_index` is omitted, it is 1 by default.
 
 Given a constraint `function-in-set`, the `ConstraintPrimal` is the value of the
 function evaluated at the primal solution of the variables. For example, given
@@ -1038,23 +1036,23 @@ a primal solution of `(x,y) = (4,5)`, the `ConstraintPrimal` solution of the
 constraint is `1 * 4 + 2 * 5 + 3 = 17`.
 """
 struct ConstraintPrimal <: AbstractConstraintAttribute
-    N::Int
+    result_index::Int
 end
 ConstraintPrimal() = ConstraintPrimal(1)
-_result_index_field(attr::ConstraintPrimal) = attr.N
+_result_index_field(attr::ConstraintPrimal) = attr.result_index
 
 """
-    ConstraintDual(N)
+    ConstraintDual(result_index)
     ConstraintDual()
 
-A constraint attribute for the assignment to some constraint's dual value(s) in result `N`.
-If `N` is omitted, it is 1 by default.
+A constraint attribute for the assignment to some constraint's dual value(s) in result `result_index`.
+If `result_index` is omitted, it is 1 by default.
 """
 struct ConstraintDual <: AbstractConstraintAttribute
-    N::Int
+    result_index::Int
 end
 ConstraintDual() = ConstraintDual(1)
-_result_index_field(attr::ConstraintDual) = attr.N
+_result_index_field(attr::ConstraintDual) = attr.result_index
 
 """
     ConstraintBasisStatus(result_index)
@@ -1268,32 +1266,32 @@ The values indicate how to interpret the result vector.
       UNKNOWN_RESULT_STATUS, OTHER_RESULT_STATUS)
 
 """
-    PrimalStatus(N)
+    PrimalStatus(result_index::Int)
     PrimalStatus()
 
-A model attribute for the `ResultStatusCode` of the primal result `N`.
-If `N` is omitted, it defaults to 1. If `N` is larger than the value of
-[`ResultCount`](@ref) then `NO_SOLUTION` is returned.
+A model attribute for the `ResultStatusCode` of the primal result `result_index`.
+If `result_index` is omitted, it defaults to 1. If `result_index` is larger than
+the value of [`ResultCount`](@ref) then `NO_SOLUTION` is returned.
 """
 struct PrimalStatus <: AbstractModelAttribute
-    N::Int
+    result_index::Int
 end
 PrimalStatus() = PrimalStatus(1)
-_result_index_field(attr::PrimalStatus) = attr.N
+_result_index_field(attr::PrimalStatus) = attr.result_index
 
 """
-    DualStatus(N)
+    DualStatus(result_index)
     DualStatus()
 
-A model attribute for the `ResultStatusCode` of the dual result `N`.
-If `N` is omitted, it defaults to 1. If `N` is larger than the value of
-[`ResultCount`](@ref) then `NO_SOLUTION` is returned.
+A model attribute for the `ResultStatusCode` of the dual result `result_index`.
+If `result_index` is omitted, it defaults to 1. If `result_index` is larger than
+the value of [`ResultCount`](@ref) then `NO_SOLUTION` is returned.
 """
 struct DualStatus <: AbstractModelAttribute
-    N::Int
+    result_index::Int
 end
 DualStatus() = DualStatus(1)
-_result_index_field(attr::DualStatus) = attr.N
+_result_index_field(attr::DualStatus) = attr.result_index
 
 """
     is_set_by_optimize(::AnyAttribute)
diff --git a/src/nlp.jl b/src/nlp.jl
index 33c1fc3bd3..5eecbfb997 100644
--- a/src/nlp.jl
+++ b/src/nlp.jl
@@ -22,17 +22,17 @@ optionally a nonlinear objective.
 struct NLPBlock <: AbstractModelAttribute end
 
 """
-    NLPBlockDual(N)
+    NLPBlockDual(result_index::Int)
     NLPBlockDual()
 
-The Lagrange multipliers on the constraints from the `NLPBlock` in result `N`.
-If `N` is omitted, it is 1 by default.
+The Lagrange multipliers on the constraints from the `NLPBlock` in result `result_index`.
+If `result_index` is omitted, it is 1 by default.
 """
 struct NLPBlockDual <: AbstractModelAttribute
-    N::Int
+    result_index::Int
 end
 NLPBlockDual() = NLPBlockDual(1)
-_result_index_field(attr::NLPBlockDual) = attr.N
+_result_index_field(attr::NLPBlockDual) = attr.result_index
 
 is_set_by_optimize(::NLPBlockDual) = true
 

From a0e3bebac55c259a5fe8d8b0b5def1443dbba087 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Fri, 10 Jan 2020 13:50:01 +0100
Subject: [PATCH 2/7] fix tests

---
 src/Bridges/Constraint/indicator_sos.jl | 4 ++--
 src/Bridges/Constraint/vectorize.jl     | 2 +-
 src/Bridges/Variable/vectorize.jl       | 4 ++--
 src/Utilities/results.jl                | 6 +++---
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/Bridges/Constraint/indicator_sos.jl b/src/Bridges/Constraint/indicator_sos.jl
index 93505b570a..c4fd9d4ed1 100644
--- a/src/Bridges/Constraint/indicator_sos.jl
+++ b/src/Bridges/Constraint/indicator_sos.jl
@@ -159,8 +159,8 @@ function MOI.supports(
 end
 
 function MOI.get(model::MOI.ModelLike, attr::MOI.ConstraintPrimal, bridge::IndicatorSOS1Bridge)
-    zvalue = MOI.get(model, MOI.VariablePrimal(attr.N), bridge.z_variable_index)
-    wvalue = MOI.get(model, MOI.VariablePrimal(attr.N), bridge.w_variable_index)
+    zvalue = MOI.get(model, MOI.VariablePrimal(attr.result_index), bridge.z_variable_index)
+    wvalue = MOI.get(model, MOI.VariablePrimal(attr.result_index), bridge.w_variable_index)
     lin_primal_start = MOI.get(model, attr, bridge.linear_constraint_index)
     return [zvalue, lin_primal_start - wvalue]
 end
diff --git a/src/Bridges/Constraint/vectorize.jl b/src/Bridges/Constraint/vectorize.jl
index 44666d941d..247176efee 100644
--- a/src/Bridges/Constraint/vectorize.jl
+++ b/src/Bridges/Constraint/vectorize.jl
@@ -72,7 +72,7 @@ function MOI.get(model::MOI.ModelLike,
     @assert length(x) == 1
     y = x[1]
     if !(attr isa MOI.ConstraintPrimal &&
-         MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.N))))
+         MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.result_index))))
        # If it is an infeasibility certificate, it is a ray and satisfies the
        # homogenized problem, see https://github.com/JuliaOpt/MathOptInterface.jl/issues/433
        # Otherwise, we need to add the set constant since the ConstraintPrimal
diff --git a/src/Bridges/Variable/vectorize.jl b/src/Bridges/Variable/vectorize.jl
index f29e489e4e..2642c91375 100644
--- a/src/Bridges/Variable/vectorize.jl
+++ b/src/Bridges/Variable/vectorize.jl
@@ -76,7 +76,7 @@ function MOI.get(model::MOI.ModelLike, attr::MOI.ConstraintPrimal,
     x = MOI.get(model, attr, bridge.vector_constraint)
     @assert length(x) == 1
     y = x[1]
-    if !MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.N)))
+    if !MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.result_index)))
        # If it is an infeasibility certificate, it is a ray and satisfies the
        # homogenized problem, see https://github.com/JuliaOpt/MathOptInterface.jl/issues/433
        # Otherwise, we need to add the set constant since the ConstraintPrimal
@@ -98,7 +98,7 @@ function MOI.get(model::MOI.ModelLike,
                  bridge::VectorizeBridge)
     value = MOI.get(model, attr, bridge.variable)
     if !(attr isa MOI.VariablePrimal &&
-         MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.N))))
+         MOIU.is_ray(MOI.get(model, MOI.PrimalStatus(attr.result_index))))
         value += bridge.set_constant
     end
     return value
diff --git a/src/Utilities/results.jl b/src/Utilities/results.jl
index c0b8e5d488..0bb395d0c7 100644
--- a/src/Utilities/results.jl
+++ b/src/Utilities/results.jl
@@ -267,7 +267,7 @@ function variable_dual(model::MOI.ModelLike,
                        ci::MOI.ConstraintIndex{<:MOI.VectorQuadraticFunction})
     func = MOI.get(model, MOI.ConstraintFunction(), ci)
     set = MOI.get(model, MOI.ConstraintSet(), ci)
-    primal_attr = MOI.VariablePrimal(attr.N)
+    primal_attr = MOI.VariablePrimal(attr.result_index)
     coef = variable_coefficient(func, vi, vi -> MOI.get(model, primal_attr, vi))
     dual = MOI.get(model, attr, ci)
     return set_dot(coef, dual, set)
@@ -286,7 +286,7 @@ function variable_dual(model::MOI.ModelLike,
                        vi::MOI.VariableIndex,
                        ci::MOI.ConstraintIndex{<:MOI.ScalarQuadraticFunction})
     func = MOI.get(model, MOI.ConstraintFunction(), ci)
-    primal_attr = MOI.VariablePrimal(attr.N)
+    primal_attr = MOI.VariablePrimal(attr.result_index)
     coef = variable_coefficient(func, vi, vi -> MOI.get(model, primal_attr, vi))
     dual = MOI.get(model, attr, ci)
     return coef * dual
@@ -369,7 +369,7 @@ function variable_dual(model::MOI.ModelLike,
             dual += sign * variable_coefficient(f, vi)
         elseif F <: MOI.ScalarQuadraticFunction
             f = MOI.get(model, obj_attr)
-            primal_attr = MOI.VariablePrimal(attr.N)
+            primal_attr = MOI.VariablePrimal(attr.result_index)
             dual += sign * variable_coefficient(f, vi, vi -> MOI.get(model, primal_attr, vi))
         else
             error("Fallback getter for variable constraint dual does not",

From 29de5620d89e398ac3d78d5ea5786169e1baac1e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Fri, 10 Jan 2020 15:13:44 +0100
Subject: [PATCH 3/7] deprecate helper function

---
 src/attributes.jl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/attributes.jl b/src/attributes.jl
index 15e4fee745..56460b2b60 100644
--- a/src/attributes.jl
+++ b/src/attributes.jl
@@ -124,7 +124,9 @@ struct ResultIndexBoundsError{AttrType} <: Exception
     result_count::Int
 end
 
-_result_index_field(attr) = attr.result_index
+# deprecate _result_index_field, no export
+@deprecate _result_index_field(attr) attr.result_index false
+
 function check_result_index_bounds(model::ModelLike, attr)
     result_count = get(model, ResultCount())
     if !(1 <= attr.result_index <= result_count)

From 5a5ac6f67d28606499f7e9f01eedc428bd4e63a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Fri, 10 Jan 2020 19:09:41 +0100
Subject: [PATCH 4/7] remove methods for result field

---
 src/attributes.jl  | 5 -----
 src/nlp.jl         | 1 -
 test/attributes.jl | 2 ++
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/attributes.jl b/src/attributes.jl
index 56460b2b60..0368c51852 100644
--- a/src/attributes.jl
+++ b/src/attributes.jl
@@ -949,7 +949,6 @@ struct VariablePrimal <: AbstractVariableAttribute
     result_index::Int
 end
 VariablePrimal() = VariablePrimal(1)
-_result_index_field(attr::VariablePrimal) = attr.result_index
 
 """
     CallbackVariablePrimal(callback_data)
@@ -1041,7 +1040,6 @@ struct ConstraintPrimal <: AbstractConstraintAttribute
     result_index::Int
 end
 ConstraintPrimal() = ConstraintPrimal(1)
-_result_index_field(attr::ConstraintPrimal) = attr.result_index
 
 """
     ConstraintDual(result_index)
@@ -1054,7 +1052,6 @@ struct ConstraintDual <: AbstractConstraintAttribute
     result_index::Int
 end
 ConstraintDual() = ConstraintDual(1)
-_result_index_field(attr::ConstraintDual) = attr.result_index
 
 """
     ConstraintBasisStatus(result_index)
@@ -1279,7 +1276,6 @@ struct PrimalStatus <: AbstractModelAttribute
     result_index::Int
 end
 PrimalStatus() = PrimalStatus(1)
-_result_index_field(attr::PrimalStatus) = attr.result_index
 
 """
     DualStatus(result_index)
@@ -1293,7 +1289,6 @@ struct DualStatus <: AbstractModelAttribute
     result_index::Int
 end
 DualStatus() = DualStatus(1)
-_result_index_field(attr::DualStatus) = attr.result_index
 
 """
     is_set_by_optimize(::AnyAttribute)
diff --git a/src/nlp.jl b/src/nlp.jl
index 5eecbfb997..be25e5310f 100644
--- a/src/nlp.jl
+++ b/src/nlp.jl
@@ -32,7 +32,6 @@ struct NLPBlockDual <: AbstractModelAttribute
     result_index::Int
 end
 NLPBlockDual() = NLPBlockDual(1)
-_result_index_field(attr::NLPBlockDual) = attr.result_index
 
 is_set_by_optimize(::NLPBlockDual) = true
 
diff --git a/test/attributes.jl b/test/attributes.jl
index e503cf5999..3fb9e32611 100644
--- a/test/attributes.jl
+++ b/test/attributes.jl
@@ -28,4 +28,6 @@
         @test_throws err MOI.set(model, MOI.VariablePrimalStart(), [x],
                                  ones(2))
     end
+    attr = MOI.VariablePrimal()
+    @test_deprecated MOI._result_index_field(attr)
 end

From 6488b9945c39f309db839b2d4ea99e346737f4c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Thu, 3 Dec 2020 20:28:12 +0100
Subject: [PATCH 5/7] fix indexing

---
 src/Bridges/Constraint/semi_to_binary.jl        | 2 +-
 src/Bridges/Constraint/soc_to_nonconvex_quad.jl | 2 +-
 src/Utilities/mockoptimizer.jl                  | 4 ++--
 src/Utilities/results.jl                        | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Bridges/Constraint/semi_to_binary.jl b/src/Bridges/Constraint/semi_to_binary.jl
index aeef00099f..e3a4a0099e 100644
--- a/src/Bridges/Constraint/semi_to_binary.jl
+++ b/src/Bridges/Constraint/semi_to_binary.jl
@@ -115,7 +115,7 @@ end
 
 function MOI.get(model::MOI.ModelLike, attr::MOI.ConstraintPrimal,
     bridge::SemiToBinaryBridge)
-    MOI.get(model, MOI.VariablePrimal(attr.N), bridge.variable_index)
+    MOI.get(model, MOI.VariablePrimal(attr.result_index), bridge.variable_index)
 end
 
 function MOI.supports(
diff --git a/src/Bridges/Constraint/soc_to_nonconvex_quad.jl b/src/Bridges/Constraint/soc_to_nonconvex_quad.jl
index 6f6c143f1b..abb0a49bd0 100644
--- a/src/Bridges/Constraint/soc_to_nonconvex_quad.jl
+++ b/src/Bridges/Constraint/soc_to_nonconvex_quad.jl
@@ -180,7 +180,7 @@ end
 # Attributes, Bridge acting as a constraint
 function MOI.get(model::MOI.ModelLike, attr::MOI.ConstraintPrimal,
                  bridge::AbstractSOCtoNonConvexQuadBridge)
-    vals = MOI.get.(model, MOI.VariablePrimal(attr.N), bridge.vars)
+    vals = MOI.get.(model, MOI.VariablePrimal(attr.result_index), bridge.vars)
     return vals
 end
 
diff --git a/src/Utilities/mockoptimizer.jl b/src/Utilities/mockoptimizer.jl
index 81b7af9d8f..076607fe5e 100644
--- a/src/Utilities/mockoptimizer.jl
+++ b/src/Utilities/mockoptimizer.jl
@@ -160,10 +160,10 @@ function MOI.set(mock::MockOptimizer, attr::MOI.DualObjectiveValue, value::Real)
     mock.dual_objective_value[attr.result_index] = value
 end
 function MOI.set(mock::MockOptimizer, attr::MOI.PrimalStatus, value::MOI.ResultStatusCode)
-    mock.primal_status[attr.N] = value
+    mock.primal_status[attr.result_index] = value
 end
 function MOI.set(mock::MockOptimizer, attr::MOI.DualStatus, value::MOI.ResultStatusCode)
-    mock.dual_status[attr.N] = value
+    mock.dual_status[attr.result_index] = value
 end
 MOI.set(mock::MockOptimizer, ::MockModelAttribute, value::Integer) = (mock.attribute = value)
 function MOI.supports(mock::MockOptimizer, attr::MOI.AbstractOptimizerAttribute)
diff --git a/src/Utilities/results.jl b/src/Utilities/results.jl
index 94ff6858be..9fcba71448 100644
--- a/src/Utilities/results.jl
+++ b/src/Utilities/results.jl
@@ -149,7 +149,7 @@ function get_fallback(model::MOI.ModelLike, attr::MOI.ConstraintPrimal,
                       idx::MOI.ConstraintIndex)
     f = MOI.get(model, MOI.ConstraintFunction(), idx)
     # TODO do not include constant if primal solution is a ray
-    return eval_variables(vi -> MOI.get(model, MOI.VariablePrimal(attr.N), vi), f)
+    return eval_variables(vi -> MOI.get(model, MOI.VariablePrimal(attr.result_index), vi), f)
 end
 
 ################ Constraint Dual for Variable-wise constraints #################

From f7ae306207e39f93b8a9e106137e1666840cafa4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Thu, 3 Dec 2020 21:22:35 +0100
Subject: [PATCH 6/7] fix deprecations

---
 src/Utilities/mockoptimizer.jl | 10 +++++-----
 src/attributes.jl              |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/Utilities/mockoptimizer.jl b/src/Utilities/mockoptimizer.jl
index 076607fe5e..9b1d58f6f4 100644
--- a/src/Utilities/mockoptimizer.jl
+++ b/src/Utilities/mockoptimizer.jl
@@ -318,14 +318,14 @@ function MOI.get(mock::MockOptimizer, attr::MOI.PrimalStatus)
     if attr.result_index > mock.result_count
         return MOI.NO_SOLUTION
     else
-        return get(mock.primal_status, attr.N, MOI.NO_SOLUTION)
+        return get(mock.primal_status, attr.result_index, MOI.NO_SOLUTION)
     end
 end
 function MOI.get(mock::MockOptimizer, attr::MOI.DualStatus)
     if attr.result_index > mock.result_count
         return MOI.NO_SOLUTION
     else
-        return get(mock.dual_status, attr.N, MOI.NO_SOLUTION)
+        return get(mock.dual_status, attr.result_index, MOI.NO_SOLUTION)
     end
 end
 MOI.get(mock::MockOptimizer, ::MockModelAttribute) = mock.attribute
@@ -402,7 +402,7 @@ function _safe_set_result(dict::Dict{K,V}, attr::MOI.AnyAttribute, index::K,
     if !haskey(dict, xored)
         dict[xored] = V()
     end
-    dict[xored][MOI._result_index_field(attr)] = value
+    dict[xored][attr.result_index] = value
 end
 function _safe_get_result(dict::Dict, attr::MOI.AnyAttribute, index::MOI.Index,
                           name::String)
@@ -411,9 +411,9 @@ function _safe_get_result(dict::Dict, attr::MOI.AnyAttribute, index::MOI.Index,
     if result_to_value === nothing
         error("No mock $name is set for ", index_name, " `", index, "`.")
     end
-    value = get(result_to_value, MOI._result_index_field(attr), nothing)
+    value = get(result_to_value, attr.result_index, nothing)
     if value === nothing
-        error("No mock $name is set for ", index_name, " `", index, "` at result index `", MOI._result_index_field(attr), "`.")
+        error("No mock $name is set for ", index_name, " `", index, "` at result index `", attr.result_index, "`.")
     end
     return value
 end
diff --git a/src/attributes.jl b/src/attributes.jl
index 49f772105a..99aa562d97 100644
--- a/src/attributes.jl
+++ b/src/attributes.jl
@@ -1004,11 +1004,11 @@ A variable attribute for the initial assignment to some primal variable's value
 struct VariablePrimalStart <: AbstractVariableAttribute end
 
 """
-    VariablePrimal(N)
+    VariablePrimal(result_index)
     VariablePrimal()
 
-A variable attribute for the assignment to some primal variable's value in result `N`.
-If `N` is omitted, it is 1 by default.
+A variable attribute for the assignment to some primal variable's value in result `result_index`.
+If `result_index` is omitted, it is 1 by default.
 """
 struct VariablePrimal <: AbstractVariableAttribute
     result_index::Int

From 952c087208c411ad1f71173a788723172690d273 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mathieu=20Besan=C3=A7on?= <mathieu.besancon@gmail.com>
Date: Fri, 4 Dec 2020 15:33:02 +0100
Subject: [PATCH 7/7] test deprecation

---
 src/MathOptInterface.jl |  2 ++
 src/attributes.jl       |  3 ---
 src/deprecate.jl        | 20 ++++++++++++++++++++
 test/attributes.jl      | 19 ++++++++++++++++++-
 4 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 src/deprecate.jl

diff --git a/src/MathOptInterface.jl b/src/MathOptInterface.jl
index 6153434604..88f84aa49a 100644
--- a/src/MathOptInterface.jl
+++ b/src/MathOptInterface.jl
@@ -139,6 +139,8 @@ include("modifications.jl")
 include("variables.jl")
 include("nlp.jl")
 
+include("deprecate.jl")
+
 # submodules
 include("Utilities/Utilities.jl") # MOI.Utilities
 include("Test/Test.jl")           # MOI.Test
diff --git a/src/attributes.jl b/src/attributes.jl
index 99aa562d97..7d4ce8859e 100644
--- a/src/attributes.jl
+++ b/src/attributes.jl
@@ -124,9 +124,6 @@ struct ResultIndexBoundsError{AttrType} <: Exception
     result_count::Int
 end
 
-# deprecate _result_index_field, no export
-@deprecate _result_index_field(attr) attr.result_index false
-
 function check_result_index_bounds(model::ModelLike, attr)
     result_count = get(model, ResultCount())
     if !(1 <= attr.result_index <= result_count)
diff --git a/src/deprecate.jl b/src/deprecate.jl
new file mode 100644
index 0000000000..63b496e3d9
--- /dev/null
+++ b/src/deprecate.jl
@@ -0,0 +1,20 @@
+# deprecate _result_index_field and accessing attr.N, no export
+@deprecate _result_index_field(attr) attr.result_index false
+
+function Base.getproperty(attr::Attr, f::Symbol) where Attr <:Union{
+                    ObjectiveValue,
+                    DualObjectiveValue,
+                    VariablePrimal,
+                    ConstraintPrimal,
+                    ConstraintDual,
+                    ConstraintBasisStatus,
+                    PrimalStatus,
+                    DualStatus,
+                    NLPBlockDual,
+                }
+    if f === :N
+        @warn "Field attr.N is deprecated, use attr.result_index"
+        return getfield(attr, :result_index)
+    end
+    return getfield(attr, f)
+end
diff --git a/test/attributes.jl b/test/attributes.jl
index de34b791ba..c8c0057153 100644
--- a/test/attributes.jl
+++ b/test/attributes.jl
@@ -30,5 +30,22 @@
                                  ones(2))
     end
     attr = MOI.VariablePrimal()
-    @test_deprecated MOI._result_index_field(attr)
+    @test_deprecated begin
+        @test MOI._result_index_field(attr) == 1
+    end
+
+    for attr_type in (
+                MOI.ObjectiveValue,
+                MOI.DualObjectiveValue,
+                MOI.VariablePrimal,
+                MOI.ConstraintPrimal,
+                MOI.ConstraintDual,
+                MOI.ConstraintBasisStatus,
+                MOI.PrimalStatus,
+                MOI.DualStatus,
+                MOI.NLPBlockDual,
+            )
+        attr = attr_type(1)
+        @test_logs (:warn, "Field attr.N is deprecated, use attr.result_index") attr.N
+    end
 end