From a4ba071e2a93583ed7984a849914a4fcdba2d1ff Mon Sep 17 00:00:00 2001
From: cstjean <st-jean.cb@om.asahi-kasei.co.jp>
Date: Tue, 20 May 2025 10:49:00 +0900
Subject: [PATCH 1/4] Fix @mtkmodel to work without `using ModelingToolkit`

See https://github.com/SciML/ModelingToolkit.jl/issues/3640

Feels like `const MTK = ModelingToolkit` should be at the top-level for
convenience.
---
 src/systems/model_parsing.jl | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/systems/model_parsing.jl b/src/systems/model_parsing.jl
index 024c249363..85a7cf354b 100644
--- a/src/systems/model_parsing.jl
+++ b/src/systems/model_parsing.jl
@@ -42,8 +42,9 @@ function flatten_equations(eqs::Vector{Union{Equation, Vector{Equation}}})
 end
 
 function _model_macro(mod, fullname::Union{Expr, Symbol}, expr, isconnector)
+    MTK = ModelingToolkit
     if fullname isa Symbol
-        name, type = fullname, :System
+        name, type = fullname, :($MTK.System)
     else
         if fullname.head == :(::)
             name, type = fullname.args
@@ -74,9 +75,9 @@ function _model_macro(mod, fullname::Union{Expr, Symbol}, expr, isconnector)
     push!(exprs.args, :(parameters = []))
     # We build `System` by default; vectors can't be created for `System` as it is
     # a function.
-    push!(exprs.args, :(systems = ModelingToolkit.AbstractSystem[]))
-    push!(exprs.args, :(equations = Union{Equation, Vector{Equation}}[]))
-    push!(exprs.args, :(defaults = Dict{Num, Union{Number, Symbol, Function}}()))
+    push!(exprs.args, :(systems = $MTK.AbstractSystem[]))
+    push!(exprs.args, :(equations = Union{$MTK.Equation, Vector{$MTK.Equation}}[]))
+    push!(exprs.args, :(defaults = Dict{$MTK.Num, Union{Number, Symbol, Function}}()))
 
     Base.remove_linenums!(expr)
     for arg in expr.args

From 23db74ee509033322e2739c8e96894076e9703db Mon Sep 17 00:00:00 2001
From: cstjean <st-jean.cb@om.asahi-kasei.co.jp>
Date: Tue, 20 May 2025 11:05:18 +0900
Subject: [PATCH 2/4] Write test for #3640

---
 test/model_parsing.jl | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/test/model_parsing.jl b/test/model_parsing.jl
index fe2bcbfca6..7d1d661139 100644
--- a/test/model_parsing.jl
+++ b/test/model_parsing.jl
@@ -1058,3 +1058,24 @@ end
     @test isequal(constrs[2], -4 + ex.y ≲ 0)
     @test ModelingToolkit.get_consolidate(ex)([1, 2]) ≈ 1 + log(2)
 end
+
+module NoUsingMTK  # From #3640
+using ModelingToolkit: @mtkmodel, @variables, @parameters, t_nounits as t
+
+@mtkmodel MyModel begin
+    @variables begin
+        x(t)
+        y(t)
+    end
+    @parameters begin
+        a
+    end
+    @equations begin
+        y ~ a * x
+    end
+end
+end
+
+@testset "Model can be defined even without `using MTK` (#3640)" begin
+    @test NoUsingMTK.MyModel(; name=:foo) isa ModelingToolkit.AbstractSystem  # just test that it ran fine
+end

From 52de720cd7b36d68fa03b441f6dac47249198859 Mon Sep 17 00:00:00 2001
From: cstjean <st-jean.cb@om.asahi-kasei.co.jp>
Date: Tue, 20 May 2025 11:17:49 +0900
Subject: [PATCH 3/4] Respect 92 char line length limit

---
 test/model_parsing.jl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/model_parsing.jl b/test/model_parsing.jl
index 7d1d661139..01c850110d 100644
--- a/test/model_parsing.jl
+++ b/test/model_parsing.jl
@@ -1077,5 +1077,6 @@ end
 end
 
 @testset "Model can be defined even without `using MTK` (#3640)" begin
-    @test NoUsingMTK.MyModel(; name=:foo) isa ModelingToolkit.AbstractSystem  # just test that it ran fine
+    # Just test that it runs without error
+    @test NoUsingMTK.MyModel(; name=:foo) isa ModelingToolkit.AbstractSystem
 end

From 321836b5c16871c509ede3083dcbb91978784986 Mon Sep 17 00:00:00 2001
From: cstjean <st-jean.cb@om.asahi-kasei.co.jp>
Date: Tue, 20 May 2025 11:20:33 +0900
Subject: [PATCH 4/4] Run JuliaFormatter

---
 test/model_parsing.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/model_parsing.jl b/test/model_parsing.jl
index 01c850110d..91b122f87c 100644
--- a/test/model_parsing.jl
+++ b/test/model_parsing.jl
@@ -1078,5 +1078,5 @@ end
 
 @testset "Model can be defined even without `using MTK` (#3640)" begin
     # Just test that it runs without error
-    @test NoUsingMTK.MyModel(; name=:foo) isa ModelingToolkit.AbstractSystem
+    @test NoUsingMTK.MyModel(; name = :foo) isa ModelingToolkit.AbstractSystem
 end