From a54be8dae6854750800f0b702c1c8218d40391fc Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Sun, 17 Jul 2022 20:58:36 -0400
Subject: [PATCH] instances supply names during reordering

---
 CHANGELOG.md                |  1 +
 src/Convert/Package.hs      |  6 +++++-
 test/core/reorder_shadow.sv | 29 +++++++++++++++++++++++++++++
 test/core/reorder_shadow.v  | 30 ++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 test/core/reorder_shadow.sv
 create mode 100644 test/core/reorder_shadow.v

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fedd040..1dde2db 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,7 @@
   accessed directly
 * Fixed conversion of casts using structs containing multi-dimensional fields
 * Fixed incorrect name resolution conflicts raised during interface inlining
+* Fixed handling of interface instances which shadow other declarations
 
 ## v0.0.9
 
diff --git a/src/Convert/Package.hs b/src/Convert/Package.hs
index 71c95e3..656cf0a 100644
--- a/src/Convert/Package.hs
+++ b/src/Convert/Package.hs
@@ -652,7 +652,7 @@ reorderGenItem item = item
 -- iteratively inserts missing package items exactly where they are needed
 addItems :: PIs -> Idents -> [(ModuleItem, Idents)] -> [ModuleItem]
 addItems pis existingPIs ((item, usedPIs) : items) =
-    if not $ Set.disjoint existingPIs thisPI then
+    if not $ forceKeep || Set.disjoint existingPIs thisPI then
         -- this item was re-imported earlier in the module
         addItems pis existingPIs items
     else if Map.null itemsToAdd then
@@ -666,7 +666,11 @@ addItems pis existingPIs ((item, usedPIs) : items) =
         thisPI = case item of
             MIPackageItem packageItem ->
                 Set.fromList $ piNames packageItem
+            Instance _ _ x _ _ -> Set.singleton x
             _ -> Set.empty
+        forceKeep = case item of
+            Instance{} -> True
+            _ -> False
         neededPIs = Set.difference (Set.difference usedPIs existingPIs) thisPI
         itemsToAdd = Map.restrictKeys pis neededPIs
         (chosenName, chosenPI) = Map.findMin itemsToAdd
diff --git a/test/core/reorder_shadow.sv b/test/core/reorder_shadow.sv
new file mode 100644
index 0000000..7192e15
--- /dev/null
+++ b/test/core/reorder_shadow.sv
@@ -0,0 +1,29 @@
+typedef logic over;
+
+interface intf;
+    logic [3:0] x;
+    assign x[0] = 0;
+    initial $display("intf x %b", x);
+endinterface
+
+module mod(intf i);
+    assign i.x[1] = 1;
+    initial $display("mod i.x %b", i.x);
+endmodule
+
+module check;
+    over y;
+    intf over();
+    mod m(over);
+    assign over.x[2] = 1'bz;
+    initial $display("check over.x %b", over.x);
+    initial $display("check y %b", y);
+endmodule
+
+module top;
+    check c();
+    intf over();
+    mod m(over);
+    assign over.x[2] = 1'bz;
+    initial $display("top over.x %b", over.x);
+endmodule
diff --git a/test/core/reorder_shadow.v b/test/core/reorder_shadow.v
new file mode 100644
index 0000000..333c05d
--- /dev/null
+++ b/test/core/reorder_shadow.v
@@ -0,0 +1,30 @@
+module check;
+    wire y;
+    if (1) begin : over
+        wire [3:0] x;
+        assign x[0] = 0;
+        initial $display("intf x %b", x);
+    end
+    if (1) begin : m
+        assign over.x[1] = 1;
+        initial $display("mod i.x %b", over.x);
+    end
+    assign over.x[2] = 1'bz;
+    initial $display("check over.x %b", over.x);
+    initial $display("check y %b", y);
+endmodule
+
+module top;
+    check c();
+    if (1) begin : over
+        wire [3:0] x;
+        assign x[0] = 0;
+        initial $display("intf x %b", x);
+    end
+    if (1) begin : m
+        assign over.x[1] = 1;
+        initial $display("mod i.x %b", over.x);
+    end
+    assign over.x[2] = 1'bz;
+    initial $display("top over.x %b", over.x);
+endmodule