diff --git a/src/Convert/Cast.hs b/src/Convert/Cast.hs
index 7bf9eee..2b7a328 100644
--- a/src/Convert/Cast.hs
+++ b/src/Convert/Cast.hs
@@ -117,12 +117,18 @@ convertCastM (Number size) (Number value) signed =
                         ++ " is not an integer"
 convertCastM size value signed = do
     value' <- traverseExprM value
-    useFn <- embedScopes canUseCastFn size
-    if useFn then do
+    sizeUsesLocalVars <- embedScopes usesLocalVars size
+    inProcedure <- withinProcedureM
+    if not sizeUsesLocalVars || not inProcedure then do
         let name = castFnName size signed
-        details <- lookupLocalIdentM name
-        when (details == Nothing) $
-            injectItem $ castFn name size signed
+        let item = castFn name size signed
+        if sizeUsesLocalVars
+            then do
+                details <- lookupLocalIdentM name
+                when (details == Nothing) (injectItem item)
+            else do
+                details <- lookupElemM name
+                when (details == Nothing) (injectTopItem item)
         return $ Call (Ident name) (Args [value'] [])
     else do
         name <- castDeclName 0
@@ -131,16 +137,19 @@ convertCastM size value signed = do
         injectDecl $ castDecl useVar name value' size signed
         return $ Ident name
 
--- checks if a cast size can be hoisted to a cast function
-canUseCastFn :: Scopes a -> Expr -> Bool
-canUseCastFn scopes size =
-    not (inProcedure && anyNonLocal)
+-- checks if a cast size references any vars not defined at the top level scope
+usesLocalVars :: Scopes a -> Expr -> Bool
+usesLocalVars scopes =
+    getAny . execWriter . collectNestedExprsM collectLocalVarsM
     where
-        inProcedure = withinProcedure scopes
-        anyNonLocal = getAny $ execWriter $
-            collectNestedExprsM collectNonLocalExprM size
-        collectNonLocalExprM :: Expr -> Writer Any ()
-        collectNonLocalExprM expr =
+        collectLocalVarsM :: Expr -> Writer Any ()
+        collectLocalVarsM expr@(Ident x) =
+            if isLoopVar scopes x
+                then tell $ Any True
+                else resolve expr
+        collectLocalVarsM expr = resolve expr
+        resolve :: Expr -> Writer Any ()
+        resolve expr =
             case lookupElem scopes expr of
                 Nothing -> return ()
                 Just ([_, _], _, _) -> return ()
diff --git a/src/Convert/Scoper.hs b/src/Convert/Scoper.hs
index f4569c9..08b1e76 100644
--- a/src/Convert/Scoper.hs
+++ b/src/Convert/Scoper.hs
@@ -38,6 +38,7 @@ module Convert.Scoper
     , scopeType
     , insertElem
     , injectItem
+    , injectTopItem
     , injectDecl
     , lookupElem
     , lookupElemM
@@ -63,6 +64,7 @@ module Convert.Scoper
 
 import Control.Monad.State.Strict
 import Data.Functor.Identity (runIdentity)
+import Data.List (partition)
 import Data.Maybe (isNothing)
 import qualified Data.Map.Strict as Map
 
@@ -97,7 +99,7 @@ data Scopes a = Scopes
     { sCurrent :: [Tier]
     , sMapping :: Mapping a
     , sProcedureLoc :: [Access]
-    , sInjectedItems :: [ModuleItem]
+    , sInjectedItems :: [(Bool, ModuleItem)]
     , sInjectedDecls :: [Decl]
     } deriving Show
 
@@ -225,7 +227,11 @@ insertElem key element = do
 
 injectItem :: Monad m => ModuleItem -> ScoperT a m ()
 injectItem item =
-    modify' $ \s -> s { sInjectedItems = item : sInjectedItems s }
+    modify' $ \s -> s { sInjectedItems = (True, item) : sInjectedItems s }
+
+injectTopItem :: Monad m => ModuleItem -> ScoperT a m ()
+injectTopItem item =
+    modify' $ \s -> s { sInjectedItems = (False, item) : sInjectedItems s }
 
 injectDecl :: Monad m => Decl -> ScoperT a m ()
 injectDecl decl =
@@ -233,10 +239,13 @@ injectDecl decl =
 
 consumeInjectedItems :: Monad m => ScoperT a m [ModuleItem]
 consumeInjectedItems = do
-    injected <- gets sInjectedItems
+    -- only pull out top items if in the top scope
+    inTopLevelScope <- gets $ (== 1) . length . sCurrent
+    let op = if inTopLevelScope then const True else fst
+    (injected, remaining) <- gets $ partition op . sInjectedItems
     when (not $ null injected) $
-        modify' $ \s -> s { sInjectedItems = [] }
-    return $ reverse injected
+        modify' $ \s -> s { sInjectedItems = remaining }
+    return $ reverse $ map snd $ injected
 
 consumeInjectedDecls :: Monad m => ScoperT a m [Decl]
 consumeInjectedDecls = do
@@ -517,7 +526,7 @@ scopeModuleItemT declMapper moduleItemMapper genItemMapper stmtMapper =
             exitProcedure
             return $ Final stmt'
         fullModuleItemMapper (Generate genItems) =
-            mapM fullGenItemMapper genItems >>= return . Generate
+            fullGenItemBlockMapper genItems >>= return . Generate
         fullModuleItemMapper (MIAttr attr item) =
             fullModuleItemMapper item >>= return . MIAttr attr
         fullModuleItemMapper item = moduleItemMapper item
@@ -526,43 +535,48 @@ scopeModuleItemT declMapper moduleItemMapper genItemMapper stmtMapper =
         fullGenItemMapper genItem = do
             genItem' <- genItemMapper genItem
             injected <- consumeInjectedItems
+            genItem'' <- scopeGenItemMapper genItem'
+            mapM_ injectItem injected -- defer until enclosing block
+            return genItem''
+
+        -- akin to fullGenItemMapper, but for lists of generate items, and
+        -- allowing module items to be injected in the middle of the list
+        fullGenItemBlockMapper :: [GenItem] -> ScoperT a m [GenItem]
+        fullGenItemBlockMapper = fmap concat . mapM genblkStep
+        genblkStep :: GenItem -> ScoperT a m [GenItem]
+        genblkStep genItem = do
+            genItem' <- fullGenItemMapper genItem
+            injected <- consumeInjectedItems
             if null injected
-                then scopeGenItemMapper genItem'
+                then return [genItem']
                 else do
                     injected' <- mapM fullModuleItemMapper injected
-                    genItem'' <- scopeGenItemMapper genItem'
-                    let genItems = map GenModuleItem injected' ++ [genItem'']
-                    -- flattened during traversal
-                    return $ GenModuleItem $ Generate genItems
+                    return $ map GenModuleItem injected' ++ [genItem']
+
+        -- enters and exits generate block scopes as appropriate
         scopeGenItemMapper :: GenItem -> ScoperT a m GenItem
+        scopeGenItemMapper (GenFor _ _ _ GenNull) = return GenNull
         scopeGenItemMapper (GenFor (index, a) b c genItem) = do
-            genItem' <- scopeGenItemBranchMapper index genItem
+            let GenBlock name genItems = genItem
+            enterScope name index
+            genItems' <- fullGenItemBlockMapper genItems
+            exitScope
+            let genItem' = GenBlock name genItems'
             return $ GenFor (index, a) b c genItem'
         scopeGenItemMapper (GenIf cond thenItem elseItem) = do
-            thenItem' <- scopeGenItemBranchMapper "" thenItem
-            elseItem' <- scopeGenItemBranchMapper "" elseItem
+            thenItem' <- fullGenItemMapper thenItem
+            elseItem' <- fullGenItemMapper elseItem
             return $ GenIf cond thenItem' elseItem'
         scopeGenItemMapper (GenBlock name genItems) = do
             enterScope name ""
-            genItems' <- mapM fullGenItemMapper genItems
+            genItems' <- fullGenItemBlockMapper genItems
             exitScope
             return $ GenBlock name genItems'
         scopeGenItemMapper (GenModuleItem moduleItem) =
             wrappedModuleItemMapper moduleItem >>= return . GenModuleItem
-        scopeGenItemMapper genItem =
+        scopeGenItemMapper genItem@GenCase{} =
             traverseSinglyNestedGenItemsM fullGenItemMapper genItem
-
-        scopeGenItemBranchMapper :: Identifier -> GenItem -> ScoperT a m GenItem
-        scopeGenItemBranchMapper index (GenBlock name genItems) = do
-            enterScope name index
-            genItems' <- mapM fullGenItemMapper genItems
-            exitScope
-            return $ GenBlock name genItems'
-        scopeGenItemBranchMapper index genItem = do
-            enterScope "" index
-            genItem' <- fullGenItemMapper genItem
-            exitScope
-            return genItem'
+        scopeGenItemMapper GenNull = return GenNull
 
 partScoper
     :: MapperM (Scoper a) Decl
diff --git a/test/core/cast_top_item.sv b/test/core/cast_top_item.sv
new file mode 100644
index 0000000..31bfad1
--- /dev/null
+++ b/test/core/cast_top_item.sv
@@ -0,0 +1,39 @@
+`ifdef REF
+    `define CHECK(N) (P & (1 << (Z+N+1) - 1))
+`else
+    `define CHECK(N) ((Z+N+1)'(P) & (1 << (Z+N+1) - 1))
+`endif
+
+`define PRINT(N) initial #P $display(`"%b bit N is set`", P);
+
+module mod;
+    parameter unsigned P = 1;
+    parameter Z = 0;
+
+    if (!Z) begin : blk1
+             if (`CHECK(0)) `PRINT(0)
+        else if (`CHECK(1)) `PRINT(1)
+        else if (`CHECK(2)) `PRINT(2)
+    end
+
+    if (!Z) begin : blk2
+        genvar i;
+        if (`CHECK(3))
+            `PRINT(3)
+        else
+            for (i = 1; i == 1 && `CHECK(4); i = i + 1)
+                `PRINT(4)
+    end
+
+    if (!Z) begin : blk3
+        wire signed x = 1;
+        `ifdef REF
+            wire [P - 1:0] tmp = x;
+            wire [7:0] y = tmp;
+        `else
+            wire [7:0] y = $unsigned(P'(x));
+        `endif
+    end
+    wire [7:0] x = blk3.y;
+    initial #P $display("%b x = %b", P, x);
+endmodule
diff --git a/test/core/cast_top_item.v b/test/core/cast_top_item.v
new file mode 100644
index 0000000..8bb983d
--- /dev/null
+++ b/test/core/cast_top_item.v
@@ -0,0 +1,2 @@
+`define REF
+`include "cast_top_item.sv"
diff --git a/test/core/cast_top_item_tb.v b/test/core/cast_top_item_tb.v
new file mode 100644
index 0000000..a3647a6
--- /dev/null
+++ b/test/core/cast_top_item_tb.v
@@ -0,0 +1,7 @@
+module top;
+    genvar i;
+    generate
+        for (i = 0; i < 32; i = i + 1)
+            mod #(i) m();
+    endgenerate
+endmodule
diff --git a/test/core/local_cast.sv b/test/core/local_cast.sv
index b5204a7..ca99121 100644
--- a/test/core/local_cast.sv
+++ b/test/core/local_cast.sv
@@ -1,17 +1,20 @@
 module top;
     generate
         for (genvar i = 1; i < 5; ++i) begin
+            localparam A = $unsigned(i'(1'sb1));
+            localparam B = $unsigned((i + 5)'(1'sb1));
             initial begin
                 integer x, y;
                 x = $unsigned(i'(1'sb1));
                 y = $unsigned((i + 5)'(1'sb1));
-                $display("%0d %b %b", i, x, y);
+                $display("%0d %b %b %b %b", i, x, y, A, B);
             end
             for (genvar j = 3; j < 6; ++j) begin
+                localparam C = $unsigned((i * j)'(1'sb1));
                 initial begin
                     integer x;
                     x = $unsigned((i * j)'(1'sb1));
-                    $display("%0d %0d %b", i, j, x);
+                    $display("%0d %0d %b %b", i, j, x, C);
                 end
             end
         end
diff --git a/test/core/local_cast.v b/test/core/local_cast.v
index 930c287..d81f107 100644
--- a/test/core/local_cast.v
+++ b/test/core/local_cast.v
@@ -2,17 +2,20 @@ module top;
     generate
         genvar i, j;
         for (i = 1; i < 5; i = i + 1) begin
+            localparam [i - 1:0] A = 1'sb1;
+            localparam [i + 4:0] B = 1'sb1;
             initial begin : foo
                 integer x, y;
                 x = $unsigned(cast_i(1'sb1));
                 y = (1 << (i + 5)) - 1;
-                $display("%0d %b %b", i, x, y);
+                $display("%0d %b %b %b %b", i, x, y, A, B);
             end
             for (j = 3; j < 6; j = j + 1) begin
+                localparam [i * j - 1:0] C = 1'sb1;
                 initial begin : bar
                     integer x;
                     x = (1 << (i * j)) - 1;
-                    $display("%0d %0d %b", i, j, x);
+                    $display("%0d %0d %b %b", i, j, x, C);
                 end
             end
             function signed [i-1:0] cast_i;
diff --git a/test/core/named_genblk_cascade.sv b/test/core/named_genblk_cascade.sv
new file mode 100644
index 0000000..2e5f4e5
--- /dev/null
+++ b/test/core/named_genblk_cascade.sv
@@ -0,0 +1,25 @@
+module mod(
+    output wire [31:0] out
+);
+    parameter P = 0;
+    if (P == 1) begin : blk1
+        wire w [2];
+    end
+    else if (P == 2) begin : blk2
+        wire x [3];
+    end
+    else if (P == 3) begin : blk3
+        wire y [5];
+    end
+    else begin : blk4
+        wire z [7];
+    end
+    if (P == 1)
+        assign out = $bits(blk1.w);
+    else if (P == 2)
+        assign out = $bits(blk2.x);
+    else if (P == 3)
+        assign out = $bits(blk3.y);
+    else
+        assign out = $bits(blk4.z);
+endmodule
diff --git a/test/core/named_genblk_cascade.v b/test/core/named_genblk_cascade.v
new file mode 100644
index 0000000..1232d87
--- /dev/null
+++ b/test/core/named_genblk_cascade.v
@@ -0,0 +1,13 @@
+module mod(
+    output wire [31:0] out
+);
+    parameter P = 0;
+    if (P == 1)
+        assign out = 2;
+    else if (P == 2)
+        assign out = 3;
+    else if (P == 3)
+        assign out = 5;
+    else
+        assign out = 7;
+endmodule
diff --git a/test/core/named_genblk_cascade_tb.v b/test/core/named_genblk_cascade_tb.v
new file mode 100644
index 0000000..532fa56
--- /dev/null
+++ b/test/core/named_genblk_cascade_tb.v
@@ -0,0 +1,7 @@
+module top;
+    wire [31:0] out1, out2, out3, out4;
+    mod #(1) m1(out1);
+    mod #(2) m2(out2);
+    mod #(3) m3(out3);
+    mod #(4) m4(out4);
+endmodule