inference: handle cases where :the_exception is used independently

`Expr(:the_exception)` is handled by the interpreter in all cases,
however, inference assumes it is only used within frames containing
`try/catch`. This commit corrects that assumption.

Compiler/src/abstractinterpretation.jl

@@ -3240,7 +3240,11 @@ function abstract_eval_throw_undef_if_not(interp::AbstractInterpreter, e::Expr,
 end
 
 function abstract_eval_the_exception(::AbstractInterpreter, sv::InferenceState)
-    (;handlers, handler_at) = sv.handler_info::HandlerInfo
+    (;handler_info) = sv
+    if handler_info === nothing
+        return the_exception_info(Any)
+    end
+    (;handlers, handler_at) = handler_info
     return the_exception_info(handlers[handler_at[sv.currpc][2]].exct)
 end
 abstract_eval_the_exception(::AbstractInterpreter, ::IRInterpretationState) = the_exception_info(Any)

Compiler/test/inference.jl

@@ -6125,3 +6125,8 @@ function func_swapglobal!_must_throw(x)
 end
 @test Base.infer_return_type(func_swapglobal!_must_throw, (Int,); interp=SwapGlobalInterp()) === Union{}
 @test !Compiler.is_effect_free(Base.infer_effects(func_swapglobal!_must_throw, (Int,); interp=SwapGlobalInterp()) )
+
+@eval get_exception() = $(Expr(:the_exception))
+@test Base.infer_return_type() do
+    get_exception()
+end <: Any