Fix invalidation in eval_rex (#729)

This invalidation was triggered by
    convert(::Type{T}, i::LoopVectorization.UpperBoundedInteger) where T<:Number
It turns out `eval_rex` had a `Core.Box` and various issues stemming from
too many small Unions for inference to succeed. Some of the later calls
imply that the type must be specific (there are no methods that can
handle the alternative type). By type-asserting that type early we avoid
the inference failures.

Author: timholy

src/packagedef.jl

@@ -311,8 +311,8 @@ function delete_missing!(mod_exs_sigs_old::ModuleExprsSigs, mod_exs_sigs_new)
 end
 
 function eval_rex(rex::RelocatableExpr, exs_sigs_old::ExprsSigs, mod::Module; mode::Symbol=:eval)
-    sigs, includes = nothing, nothing
-    with_logger(_debug_logger) do
+    return with_logger(_debug_logger) do
+        sigs, includes = nothing, nothing
         rexo = getkey(exs_sigs_old, rex, nothing)
         # extract the signatures and update the line info
         if rexo === nothing
@@ -338,9 +338,10 @@ function eval_rex(rex::RelocatableExpr, exs_sigs_old::ExprsSigs, mod::Module; mo
             # Update location info
             ln, lno = firstline(unwrap(rex)), firstline(unwrap(rexo))
             if sigs !== nothing && !isempty(sigs) && ln != lno
+                ln, lno = ln::LineNumberNode, lno::LineNumberNode
                 @debug "LineOffset" _group="Action" time=time() deltainfo=(sigs, lno=>ln)
                 for sig in sigs
-                    locdefs = CodeTracking.method_info[sig]
+                    locdefs = CodeTracking.method_info[sig]::AbstractVector
                     ld = map(pr->linediff(lno, pr[1]), locdefs)
                     idx = argmin(ld)
                     if ld[idx] === typemax(eltype(ld))
@@ -352,8 +353,8 @@ function eval_rex(rex::RelocatableExpr, exs_sigs_old::ExprsSigs, mod::Module; mo
                 end
             end
         end
+        return sigs, includes
     end
-    return sigs, includes
 end
 
 # These are typically bypassed in favor of expression-by-expression evaluation to