add check to the pass instead

src/passes.jl

@@ -256,6 +256,13 @@ end
 function short_to_long_function_def!(fst::FST, s::State)
     (fst[1].typ !== Call && fst[1].typ !== Where) && return false
 
+    # do not apply if parent is a function or macro definition
+    parent_is(
+        fst.ref[],
+        n -> is_function_or_macro_def(n) || n.head == :macrocall;
+        ignore = n -> is_block(n),
+    ) && return false
+
     # 3 cases
     #
     # case 1

src/styles/sciml/nest.jl

@@ -38,14 +38,7 @@ function n_binaryopcall!(ss::SciMLStyle, fst::FST, s::State; indent::Int = -1)
     line_margin = s.line_offset + length(fst) + fst.extra_margin
     if line_margin > s.opts.margin &&
        fst.ref !== nothing &&
-       (
-           !parent_is(
-               fst.ref[],
-               n -> is_function_or_macro_def(n) || n.head == :macrocall;
-               ignore = n -> is_block(n),
-           )
-       )
-        CSTParser.defines_function(fst.ref[])
+       CSTParser.defines_function(fst.ref[])
         transformed = short_to_long_function_def!(fst, s)
         transformed && nest!(style, fst, s)
     end

test/issues.jl

@@ -1706,4 +1706,25 @@
         """
         @test fmt(str_, 4, 92, join_lines_based_on_source = true) == str
     end
+
+    @testset "753" begin
+        str_ = """
+        using ModelingToolkit
+        @mtkmodel A begin
+                @variables begin
+                        i(t) = 0.0, [description = "Line longer than the char limit of 94 characters", unit = u"A"]
+                end
+        end
+        """
+        str = """
+        using ModelingToolkit
+        @mtkmodel A begin
+            @variables begin
+                i(t) = 0.0,
+                [description = "Line longer than the char limit of 94 characters", unit = u"A"]
+            end
+        end
+        """
+        @test format_text(str_, SciMLStyle()) == str
+    end
 end