groebner bug and correct solve_for deprecation

ext/SymbolicsGroebnerExt.jl

@@ -91,7 +91,13 @@ function Symbolics.solve_multivar(eqs::Vector, vars::Vector{Num}; dropmultiplici
         for i = 1:(old_len)
             eq += BigInt(rand(-n_iterations:n_iterations))*vars[i]
         end
+
+        if isequal(eq, new_var)
+            continue
+        end
+
         push!(new_eqs, eq)
+
         new_eqs = convert(Vector{Any}, Symbolics.groebner_basis(new_eqs, ordering=Lex(vars)))
 
         if length(new_eqs) <= length(vars) 
@@ -102,6 +108,10 @@ function Symbolics.solve_multivar(eqs::Vector, vars::Vector{Num}; dropmultiplici
             generating |= all(Symbolics.degree(var) > 1 for var in Symbolics.get_variables(new_eqs[i]))
         end
 
+        if isequal(new_eqs[1], new_var)
+            generating = true
+        end
+
         n_iterations += 1
     end
 

src/linear_algebra.jl

@@ -67,7 +67,7 @@ function A_b(eqs::AbstractArray, vars::AbstractArray, check)
     A, b
 end
 
-function solve_for(eq::Any, var::Any)
+function solve_for(eq::Any, var::Any; simplify=false, check=true)
     Base.depwarn("solve_for is deprecated, please use symbolic_linear_solve instead.", :solve_for, force=true)
     return symbolic_linear_solve(eq, var)
 end