Fix variable conflict when multiple cells with unused input defaults

src/V3Inline.cpp

@@ -342,7 +342,8 @@ class InlineRelinkVisitor final : public VNVisitor {
             // variable that will later be pruned (it will otherwise be unreferenced).
             if (!nodep->access().isReadOnly()) {
                 AstVar* const varp = nodep->varp();
-                const std::string name = "__vInlPlaceholder_" + std::to_string(++m_nPlaceholders);
+                const std::string name
+                    = m_cellp->name() + "__vInlPlaceholder_" + std::to_string(++m_nPlaceholders);
                 AstVar* const holdep = new AstVar{varp->fileline(), VVarType::VAR, name, varp};
                 m_modp->addStmtsp(holdep);
                 AstVarRef* const newp = new AstVarRef{nodep->fileline(), holdep, nodep->access()};

test_regress/t/t_module_input_default_value.v

@@ -82,6 +82,12 @@ module t
      /*.i(),*/
      .o(dut0_o_default));
 
+  logic dut0_o_default_b;
+  dut_default_input0 u_dut0_default_b
+    (.required_input(1),
+     /*.i(),*/
+     .o(dut0_o_default_b));
+
   logic dut1_o_default;
   dut_default_input1 u_dut1_default
     (/*.i(),*/
@@ -101,6 +107,11 @@ module t
     (.required_input(1),
      .i(),  // open
      .o(dut0_o_open));
+  logic        dut0_o_open_b;
+  dut_default_input0 u_dut0_open_b
+    (.required_input(1),
+     .i(),  // open
+     .o(dut0_o_open_b));
 
   logic        dut1_o_open;
   dut_default_input1 u_dut1_open
@@ -122,11 +133,16 @@ module t
   // 3. DUT instances with overriden values
   // instance names are u_dut*_overriden
   // Have u_dut0_overriden get its overriden value from a signal
-  logic        dut0_o_overriden;
+  logic dut0_o_overriden;
   dut_default_input0 u_dut0_overriden
     (.required_input(1),
      .i(logic1),  // from wire
      .o(dut0_o_overriden));
+  logic dut0_o_overriden_b;
+  dut_default_input0 u_dut0_overriden_b
+    (.required_input(1),
+     .i(logic1),  // from wire
+     .o(dut0_o_overriden_b));
 
   // Have u_dut1_overriden get its overriden value from a function.
   logic        dut1_o_overriden;