[ImportVerilog] Ignore type parameters

Ignore type parameter AST nodes since these are already handled during
Slang's type checking pass. Also tweak the diagnostics on unsupported
SV constructs to be a bit more descriptive.

lib/Conversion/ImportVerilog/Structure.cpp

@@ -97,6 +97,9 @@ struct PackageVisitor : public BaseVisitor {
   // Ignore parameters. These are materialized on-the-fly as `ConstantOp`s.
   LogicalResult visit(const slang::ast::ParameterSymbol &) { return success(); }
   LogicalResult visit(const slang::ast::SpecparamSymbol &) { return success(); }
+  LogicalResult visit(const slang::ast::TypeParameterSymbol &) {
+    return success();
+  }
 
   // Handle functions and tasks.
   LogicalResult visit(const slang::ast::SubroutineSymbol &subroutine) {
@@ -106,7 +109,7 @@ struct PackageVisitor : public BaseVisitor {
   /// Emit an error for all other members.
   template <typename T>
   LogicalResult visit(T &&node) {
-    mlir::emitError(loc, "unsupported construct: ")
+    mlir::emitError(loc, "unsupported package member: ")
         << slang::ast::toString(node.kind);
     return failure();
   }
@@ -192,6 +195,12 @@ struct ModuleVisitor : public BaseVisitor {
     return success();
   }
 
+  // Ignore type parameters. These have already been handled by Slang's type
+  // checking.
+  LogicalResult visit(const slang::ast::TypeParameterSymbol &) {
+    return success();
+  }
+
   // Handle instances.
   LogicalResult visit(const slang::ast::InstanceSymbol &instNode) {
     using slang::ast::ArgumentDirection;
@@ -515,7 +524,7 @@ struct ModuleVisitor : public BaseVisitor {
   /// Emit an error for all other members.
   template <typename T>
   LogicalResult visit(T &&node) {
-    mlir::emitError(loc, "unsupported construct: ")
+    mlir::emitError(loc, "unsupported module member: ")
         << slang::ast::toString(node.kind);
     return failure();
   }
@@ -632,7 +641,7 @@ Context::convertModuleHeader(const slang::ast::InstanceBodySymbol *module) {
   // only minor differences in semantics.
   if (module->getDefinition().definitionKind !=
       slang::ast::DefinitionKind::Module) {
-    mlir::emitError(loc) << "unsupported construct: "
+    mlir::emitError(loc) << "unsupported definition: "
                          << module->getDefinition().getKindString();
     return {};
   }

test/Conversion/ImportVerilog/basic.sv

@@ -32,7 +32,7 @@ endmodule
 // CHECK: moore.module private @DedupB(in %a : !moore.i32)
 // CHECK: moore.module private @DedupB_0(in %a : !moore.i16)
 // CHECK-NOT: @DedupB
-module DedupB #(parameter int W)(input bit [W-1:0] a);
+module DedupB #(parameter int W, parameter type T = bit [W-1:0])(input T a);
 endmodule
 
 // CHECK-LABEL: moore.module @Dedup()

test/Conversion/ImportVerilog/errors.sv

@@ -28,13 +28,13 @@ endmodule
 // -----
 module Foo;
   parameter a = 1;
-  // expected-error @below {{unsupported construct}}
+  // expected-error @below {{unsupported module member}}
   defparam a = 2;
 endmodule
 
 // -----
 module Foo;
-  // expected-error @below {{unsupported construct}}
+  // expected-error @below {{unsupported module member}}
   nettype real x;
 endmodule