Minor type stability improvements (#73)

Fixing several type instabilities that I noticed while reviewing the
code. Probably does not have much impact on compilation/runtime
performance.

Author: aviatesk

src/eval.jl

@@ -287,21 +287,25 @@ function _to_lowered_expr(ex::SyntaxTree, stmt_offset::Int)
     elseif k == K"method"
         cs = map(e->_to_lowered_expr(e, stmt_offset), children(ex))
         # Ad-hoc unwrapping to satisfy `Expr(:method)` expectations
-        c1 = cs[1] isa QuoteNode ? cs[1].value : cs[1]
+        cs1 = cs[1]
+        c1 = cs1 isa QuoteNode ? cs1.value : cs1
         Expr(:method, c1, cs[2:end]...)
     elseif k == K"newvar"
         Core.NewvarNode(_to_lowered_expr(ex[1], stmt_offset))
     elseif k == K"opaque_closure_method"
         args = map(e->_to_lowered_expr(e, stmt_offset), children(ex))
         # opaque_closure_method has special non-evaluated semantics for the
         # `functionloc` line number node so we need to undo a level of quoting
-        @assert args[4] isa QuoteNode
-        args[4] = args[4].value
+        arg4 = args[4]
+        @assert arg4 isa QuoteNode
+        args[4] = arg4.value
         Expr(:opaque_closure_method, args...)
     elseif k == K"meta"
         args = Any[_to_lowered_expr(e, stmt_offset) for e in children(ex)]
         # Unpack K"Symbol" QuoteNode as `Expr(:meta)` requires an identifier here.
-        args[1] = args[1].value
+        arg1 = args[1]
+        @assert arg1 isa QuoteNode
+        args[1] = arg1.value
         Expr(:meta, args...)
     elseif k == K"static_eval"
         @assert numchildren(ex) == 1
@@ -339,7 +343,11 @@ function _to_lowered_expr(ex::SyntaxTree, stmt_offset::Int)
         if isnothing(head)
             throw(LoweringError(ex, "Unhandled form for kind $k"))
         end
-        Expr(head, map(e->_to_lowered_expr(e, stmt_offset), children(ex))...)
+        ret = Expr(head)
+        for e in children(ex)
+            push!(ret.args, _to_lowered_expr(e, stmt_offset))
+        end
+        return ret
     end
 end
 

src/macro_expansion.jl

@@ -216,7 +216,7 @@ function expand_macro(ctx, ex)
     # We use a specific well defined world age for the next checks and macro
     # expansion invocations. This avoids inconsistencies if the latest world
     # age changes concurrently.
-    # 
+    #
     # TODO: Allow this to be passed in
     if hasmethod(macfunc, Tuple{typeof(mctx), typeof.(raw_args)...}; world=ctx.macro_world)
         macro_args = prepare_macro_args(ctx, mctx, raw_args)

src/runtime.jl

@@ -195,10 +195,10 @@ function eval_closure_type(mod::Module, closure_type_name::Symbol, field_names,
 end
 
 # Interpolate captured local variables into the CodeInfo for a global method
-function replace_captured_locals!(codeinfo, locals)
+function replace_captured_locals!(codeinfo::Core.CodeInfo, locals::Core.SimpleVector)
     for (i, ex) in enumerate(codeinfo.code)
         if Meta.isexpr(ex, :captured_local)
-            codeinfo.code[i] = locals[ex.args[1]]
+            codeinfo.code[i] = locals[ex.args[1]::Int]
         end
     end
     codeinfo