more fixes

Author: shashi

src/systems/abstractsystem.jl

@@ -193,10 +193,11 @@ function namespace_expr(O::Sym,name,ivname)
     O.name == ivname ? O : rename(O,renamespace(name,O.name))
 end
 
+_symparam(s::Symbolic{T}) where {T} = T
 function namespace_expr(O,name,ivname) where {T}
     if istree(O)
         if operation(O) isa Sym
-            Term{symtype(O)}(rename(operation(O),renamespace(name,operation(O).name)),namespace_expr.(arguments(O),name,ivname))
+            Term{_symparam(O)}(rename(operation(O),renamespace(name,operation(O).name)),namespace_expr.(arguments(O),name,ivname))
         else
             similarterm(O,operation(O),namespace_expr.(arguments(O),name,ivname))
         end

src/utils.jl

@@ -131,7 +131,10 @@ julia> substitute(ex, Dict([x => z, sin(z) => z^2]))
 (z(t) + y) + (z(t) ^ 2)
 ```
 """
-substitute(expr::Num, s::Union{Pair, Vector, Dict}; kw...) = Num(substituter(s)(value(expr); kw...))
+# cannot use Union{Pair, Vector, Dict} -- leads to ambiguity
+substitute(expr::Num, s::Pair; kw...) = Num(substituter(s)(value(expr); kw...))
+substitute(expr::Num, s::Vector; kw...) = Num(substituter(s)(value(expr); kw...))
+substitute(expr::Num, s::Dict; kw...) = Num(substituter(s)(value(expr); kw...))
 # TODO: move this to SymbolicUtils
 substitute(expr, s::Pair; kw...) = substituter([s[1] => s[2]])(expr; kw...)
 substitute(expr, s::Vector; kw...) = substituter(s)(expr; kw...)

test/function_registration.jl

@@ -76,7 +76,7 @@ foo(x, y) = sin(x) * cos(y)
 @parameters t; @variables x(t) y(t) z(t); @derivatives D'~t;
 @register foo(x, y)
 
-using ModelingToolkit: value
+using ModelingToolkit: value, arguments, operation
 expr = value(foo(x, y))
 @test operation(expr) === foo
 @test arguments(expr)[1] === value(x)