Merge pull request JuliaLang#14823 from JuliaLang/jb/fixthing

fix UndefVarError problem

src/gf.c

@@ -443,11 +443,13 @@ void jl_type_infer(jl_lambda_info_t *li, jl_tupletype_t *argtypes, jl_lambda_inf
 #endif
 #ifdef ENABLE_INFERENCE
  jl_value_t *newast = jl_apply(jl_typeinf_func, fargs, 4);
+ jl_value_t *defast = def->ast;
  li->ast = jl_fieldref(newast, 0);
  jl_gc_wb(li, li->ast);
  li->rettype = jl_fieldref(newast, 1);
  jl_gc_wb(li, li->rettype);
- li->inferred = 1;
+ // if type inference bails out it returns def->ast
+ li->inferred = li->ast != defast;
 #endif
  li->inInference = 0;
  }

test/linalg/tridiag.jl

@@ -105,6 +105,10 @@ for elty in (Float32, Float64, Complex64, Complex128, Int)
  @test eigvecs(Ts) == eigvecs(Fs)
  #call to LAPACK.stein here
  Test.test_approx_eq_modphase(eigvecs(Ts,eigvals(Ts)),eigvecs(Fs))
+ elseif elty != Int
+ # check that undef is determined accurately even if type inference
+ # bails out due to the number of try/catch blocks in this code.
+ @test_throws UndefVarError Fs
  end
 
  # Test det(A::Matrix)