From b09fdaf76a75292d7be7183aad040e2831d2b370 Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Tue, 8 Aug 2023 22:30:36 -0400
Subject: [PATCH] simplify shadowing notes non-trivial localparams too

---
 CHANGELOG.md                             |  1 +
 src/Convert/Simplify.hs                  | 11 +++++------
 test/basic/simplify_localparam_shadow.sv | 10 ++++++++++
 3 files changed, 16 insertions(+), 6 deletions(-)
 create mode 100644 test/basic/simplify_localparam_shadow.sv

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8ea7d50..b09695a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 ### Bug Fixes
 
 * Fixed an issue that prevented parsing tasks and functions with `inout` ports
+* Fixed errant constant folding of shadowed non-trivial localparams
 * Fixed certain non-ANSI style port declarations being incorrectly reported as
   incompatible
 
diff --git a/src/Convert/Simplify.hs b/src/Convert/Simplify.hs
index 2734b84..d1aad2c 100644
--- a/src/Convert/Simplify.hs
+++ b/src/Convert/Simplify.hs
@@ -17,8 +17,6 @@
 
 module Convert.Simplify (convert) where
 
-import Control.Monad (when)
-
 import Convert.ExprUtils
 import Convert.Scoper
 import Convert.Traverse
@@ -53,13 +51,14 @@ pattern SimpleVector sg l r <- IntegerVector _ sg [(RawNum l, RawNum r)]
 insertExpr :: Identifier -> Expr -> Scoper Expr ()
 insertExpr ident expr = do
     expr' <- substituteExprM expr
-    case expr' of
+    insertElem ident $ case expr' of
         Cast (Left (SimpleVector sg l r)) (Number n) ->
-            insertElem ident $ Number $ numberCast signed size n
+            Number $ numberCast signed size n
             where
                 signed = sg == Signed
                 size = fromIntegral $ abs $ l - r + 1
-        _ -> when (isSimpleExpr expr') $ insertElem ident expr'
+        _ | isSimpleExpr expr' -> expr'
+        _ -> Nil
 
 isSimpleExpr :: Expr -> Bool
 isSimpleExpr Number{}  = True
@@ -84,7 +83,7 @@ traverseGenItemM :: GenItem -> Scoper Expr GenItem
 traverseGenItemM = traverseGenItemExprsM traverseExprM
 
 traverseStmtM :: Stmt -> Scoper Expr Stmt
-traverseStmtM stmt = traverseStmtExprsM traverseExprM stmt
+traverseStmtM = traverseStmtExprsM traverseExprM
 
 traverseExprM :: Expr -> Scoper Expr Expr
 traverseExprM = embedScopes convertExpr
diff --git a/test/basic/simplify_localparam_shadow.sv b/test/basic/simplify_localparam_shadow.sv
new file mode 100644
index 0000000..0146d80
--- /dev/null
+++ b/test/basic/simplify_localparam_shadow.sv
@@ -0,0 +1,10 @@
+module top;
+    localparam i = 1234;
+    if (1) begin
+        genvar j;
+        for (j = 0; j < 10; j = j + 1) begin
+            localparam i = j;
+            initial $display(i > 5 ? i + 100 : i - 100);
+        end
+    end
+endmodule