Fix accidental shadowing

Author: YingboMa

test/reduction.jl

@@ -218,15 +218,15 @@ sys = structural_simplify(sys′)
 @variables E(t) C(t) S(t) P(t)
 D = Differential(t)
 
-equations = [
-             D(E) ~ k₋₁ * C - k₁ * E * S
-             D(C) ~ k₁ * E * S - k₋₁ * C - k₂ * C
-             D(S) ~ k₋₁ * C - k₁ * E * S
-             D(P) ~ k₂ * C
-             E₀ ~ E + C
-            ]
-
-@named sys = ODESystem(equations, t, [E, C, S, P], [k₁, k₂, k₋₁, E₀])
+eqs = [
+       D(E) ~ k₋₁ * C - k₁ * E * S
+       D(C) ~ k₁ * E * S - k₋₁ * C - k₂ * C
+       D(S) ~ k₋₁ * C - k₁ * E * S
+       D(P) ~ k₂ * C
+       E₀ ~ E + C
+      ]
+
+@named sys = ODESystem(eqs, t, [E, C, S, P], [k₁, k₂, k₋₁, E₀])
 @test_throws ModelingToolkit.InvalidSystemException structural_simplify(sys)
 
 # Example 5 from Pantelides' original paper