diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index bbaeea1a40..7f934a5769 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -224,6 +224,34 @@ PrecompileTools.@compile_workload begin
     @variables x(ModelingToolkit.t_nounits)
     @named sys = ODESystem([ModelingToolkit.D_nounits(x) ~ -x], ModelingToolkit.t_nounits)
     prob = ODEProblem(structural_simplify(sys), [x => 30.0], (0, 100), [], jac = true)
+    @mtkmodel __testmod__ begin
+        @constants begin
+            c = 1.0
+        end
+        @structural_parameters begin
+            structp = false
+        end
+        if structp
+            @variables begin
+                x(t) = 0.0, [description = "foo", guess = 1.0]
+            end
+        else
+            @variables begin
+                x(t) = 0.0, [description = "foo w/o structp", guess = 1.0]
+            end
+        end
+        @parameters begin
+            a = 1.0, [description = "bar"]
+            if structp
+                b = 2 * a, [description = "if"]
+            else
+                c
+            end
+        end
+        @equations begin
+            x ~ a + b
+        end
+    end
 end
 
 export AbstractTimeDependentSystem,
diff --git a/src/systems/model_parsing.jl b/src/systems/model_parsing.jl
index 1976e89aa2..4632c1b889 100644
--- a/src/systems/model_parsing.jl
+++ b/src/systems/model_parsing.jl
@@ -246,8 +246,10 @@ end
 # The comments indicate the syntax matched by a block; either when parsed directly
 # when it is called recursively for parsing a part of an expression.
 # These variable definitions are part of test suite in `test/model_parsing.jl`
-function parse_variable_def!(dict, mod, arg, varclass, kwargs, where_types;
+Base.@nospecializeinfer function parse_variable_def!(
+        dict, mod, arg, varclass, kwargs, where_types;
         def = nothing, type::Type = Real, meta = Dict{DataType, Expr}())
+    @nospecialize
     arg isa LineNumberNode && return
     MLStyle.@match arg begin
         # Parses: `a`
@@ -1355,7 +1357,9 @@ push_something!(v, x...) = push_something!.(Ref(v), x)
 
 define_blocks(branch) = [Expr(branch), Expr(branch), Expr(branch), Expr(branch)]
 
-function parse_top_level_branch(condition, x, y = nothing, branch = :if)
+Base.@nospecializeinfer function parse_top_level_branch(
+        condition, x, y = nothing, branch::Symbol = :if)
+    @nospecialize
     blocks::Vector{Union{Expr, Nothing}} = component_blk, equations_blk, parameter_blk, variable_blk = define_blocks(branch)
 
     for arg in x