diff --git a/.github/bin/smoke-test.sh b/.github/bin/smoke-test.sh
index d10251b..5532187 100755
--- a/.github/bin/smoke-test.sh
+++ b/.github/bin/smoke-test.sh
@@ -29,17 +29,13 @@
 # crash Verible, we're good.
 ###
 
-# Suppress '... aborted' messages bash would print when a tool crashes.
-# Comment out to see syntax errors in bash while working on script.
-exec 2>/dev/null
-
 set -u   # Be strict: only allow using a variable after it is assigned
 
 BAZEL_BUILD_OPTIONS="-c opt"
 
 TMPDIR="${TMPDIR:-/tmp}"
 readonly BASE_TEST_DIR="${TMPDIR}/test/verible-smoke-test"
-readonly DEFAULT_HASH_FILE="$(dirname $0)/smoke-projects.hashes"
+readonly PROJECT_HASHES_FILE="$(dirname $0)/smoke-projects.hashes"
 
 # Write log files to this directory
 readonly SMOKE_LOGGING_DIR="${SMOKE_LOGGING_DIR:-$BASE_TEST_DIR/error-logs}"
@@ -82,7 +78,6 @@
 #
 # There are some known issues which are all recorded in the associative
 # array below, mapping them to Verible issue tracker numbers.
-readonly PROJECT_HASHES_FILE="${1:-${DEFAULT_HASH_FILE}}"
 
 if [ ! -f "${PROJECT_HASHES_FILE}" ]; then
   echo "Project hashes file not found: ${PROJECT_HASHES_FILE}"
@@ -359,8 +354,55 @@
   return ${result}
 }
 
+# --- main
+
+KEEP_LOGS=0
+VERBOSE=0
+PROJECT_FILTER=""
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --keep-logs)
+      KEEP_LOGS=1
+      shift
+      ;;
+    --verbose|-v)
+      VERBOSE=1
+      shift
+      ;;
+    --filter=*)
+      PROJECT_FILTER="${1#*=}"
+      shift
+      ;;
+    --filter|-f)
+      if [[ $# -lt 2 ]]; then
+        echo "Error: $1 requires an argument." >&2
+        exit 1
+      fi
+      PROJECT_FILTER="$2"
+      shift 2
+      ;;
+    -h|--help)
+      echo "Usage: $0 [--keep-logs] [--verbose] [--filter=<name>]"
+      exit 0
+      ;;
+    *)
+      echo "Unknown option: $1" >&2
+      echo "Usage: $0 [--keep-logs] [--verbose] [--filter=<name>]" >&2
+      exit 1
+      ;;
+  esac
+done
+
+if [ ${VERBOSE} -eq 0 ]; then
+  # Suppress '... aborted' messages bash would print when a tool crashes.
+  exec 2>/dev/null
+fi
+
 mkdir -p "${BASE_TEST_DIR}"
-trap 'rm -rf -- "${BASE_TEST_DIR}"' EXIT
+if [ ${KEEP_LOGS} -eq 0 ]; then
+  trap 'rm -rf -- "${BASE_TEST_DIR}"' EXIT
+fi
 
 status_sum=0
 
@@ -378,6 +420,9 @@
 while read -r git_hash git_project _; do
   [[ -z "${git_hash}" || "${git_hash}" =~ ^# ]] && continue
   PROJECT_NAME="$(basename "${git_project}")"
+  if [[ -n "${PROJECT_FILTER}" && "${PROJECT_NAME}" != *"${PROJECT_FILTER}"* ]]; then
+    continue
+  fi
   PROJECT_DIR="${BASE_TEST_DIR}/${PROJECT_NAME}"
   ( git clone "${git_project}" "${PROJECT_DIR}" && git -C "${PROJECT_DIR}" checkout -q "${git_hash}" ) 2>/dev/null &
 done < "${PROJECT_HASHES_FILE}"
@@ -389,6 +434,9 @@
 while read -r git_hash git_project _; do
   [[ -z "${git_hash}" || "${git_hash}" =~ ^# ]] && continue
   PROJECT_NAME="$(basename "${git_project}")"
+  if [[ -n "${PROJECT_FILTER}" && "${PROJECT_NAME}" != *"${PROJECT_FILTER}"* ]]; then
+    continue
+  fi
   PROJECT_DIR="${BASE_TEST_DIR}/${PROJECT_NAME}"
   # Already cloned above
 
@@ -411,7 +459,7 @@
 echo "There were a total of ${status_sum} mismatches"
 
 # Let's see if there are any issues that are fixed in the meantime.
-if [ "${#KnownIssue[@]}" -ne 0 ]; then
+if [ -z "${PROJECT_FILTER}" ] && [ "${#KnownIssue[@]}" -ne 0 ]; then
   echo "::warning ::There are ${#KnownIssue[@]} tool/file combinations, that no longer fail"
   declare -A DistinctIssues
   for key in "${!KnownIssue[@]}"; do
@@ -423,7 +471,10 @@
   for issue_id in "${!DistinctIssues[@]}"; do
     echo " 🐞 ${ISSUE_PREFIX}/${issue_id}"
   done
-  echo
+fi
+
+if [ ${KEEP_LOGS} -ne 0 ]; then
+  echo "Logs and project files kept in ${BASE_TEST_DIR} (error logs: ${SMOKE_LOGGING_DIR})"
 fi
 
 exit ${status_sum}
diff --git a/README.md b/README.md
index b813b76..047fb20 100644
--- a/README.md
+++ b/README.md
@@ -172,8 +172,9 @@
 
 Verible's code base is written in C++.
 
-To build, you need the [bazel] build system (Min version 7) and a C++20
-compatible compiler.
+To build, you need the [bazel] build system (get it from
+[bazel install][bazel-install] if not already on your system) and a
+C++20 compatible compiler.
 
 Use your package manager to install the dependencies; on a system with
 the nix package manager simply run `nix-shell` to get a build environment.
@@ -199,6 +200,8 @@
 bazel build -c opt --config=create_static_linked_executables //...
 ```
 
+See [Installation](#installation-1) for install.
+
 ### Optionally using local flex/bison for build
 
 Flex and Bison, that are needed for the parser generation, are compiled as part
@@ -283,6 +286,7 @@
 [UHDM] format. If you are interested in collaborating, contact us.
 
 [bazel]: https://bazel.build/
+[bazel-install]: https://bazel.build/install
 [SV-LRM]: https://ieeexplore.ieee.org/document/8299595
 [lint-rule-list]: https://chipsalliance.github.io/verible/lint.html
 [github-lint-action]: https://github.com/chipsalliance/verible-linter-action
diff --git a/shell.nix b/shell.nix
index 85163eb..408340b 100644
--- a/shell.nix
+++ b/shell.nix
@@ -8,6 +8,17 @@
   #verible_used_stdenv = pkgs.gcc15Stdenv;
   #verible_used_stdenv = pkgs.clang19Stdenv;
   bazel = pkgs.bazel_8;
+
+
+  userNixPath = ./user.nix;  # optional user config
+  userPackages =
+    if builtins.pathExists userNixPath
+    then
+      let loaded = import userNixPath;
+      in if builtins.isFunction loaded
+         then loaded { inherit pkgs; }
+         else loaded
+    else [];
 in
 verible_used_stdenv.mkDerivation {
   name = "verible-build-environment";
@@ -40,7 +51,7 @@
 
       llvmPackages_22.clang-tools    # for clang-tidy
       llvmPackages_19.clang-tools    # for clang-format
-    ];
+    ] ++ userPackages;
   shellHook = ''
       # clang tidy: use latest.
       export CLANG_TIDY=${pkgs.llvmPackages_22.clang-tools}/bin/clang-tidy
diff --git a/verible/common/util/container-proxy_test.cc b/verible/common/util/container-proxy_test.cc
index 5e8220f..4e4cd75 100644
--- a/verible/common/util/container-proxy_test.cc
+++ b/verible/common/util/container-proxy_test.cc
@@ -874,13 +874,14 @@
 
   const int new_capacity = initial_capacity + 42;
   this->proxy.reserve(new_capacity);
-  EXPECT_EQ(this->proxy.capacity(), new_capacity);
-  EXPECT_EQ(this->container.capacity(), new_capacity);
+  EXPECT_GE(this->proxy.capacity(), new_capacity);
+  EXPECT_EQ(this->proxy.capacity(), this->container.capacity());
 
+  const int capacity_after_first_reserve = this->proxy.capacity();
   const int lower_capacity = 1;
   this->proxy.reserve(lower_capacity);
-  EXPECT_EQ(this->proxy.capacity(), new_capacity);
-  EXPECT_EQ(this->container.capacity(), new_capacity);
+  EXPECT_EQ(this->proxy.capacity(), capacity_after_first_reserve);
+  EXPECT_EQ(this->container.capacity(), capacity_after_first_reserve);
 }
 
 }  // namespace
diff --git a/verible/verilog/analysis/checkers/BUILD b/verible/verilog/analysis/checkers/BUILD
index bd3a98b..4681607 100644
--- a/verible/verilog/analysis/checkers/BUILD
+++ b/verible/verilog/analysis/checkers/BUILD
@@ -817,6 +817,7 @@
         "//verible/common/analysis:syntax-tree-lint-rule",
         "//verible/common/analysis/matcher",
         "//verible/common/analysis/matcher:bound-symbol-manager",
+        "//verible/common/text:config-utils",
         "//verible/common/text:symbol",
         "//verible/common/text:syntax-tree-context",
         "//verible/common/text:token-info",
@@ -826,7 +827,9 @@
         "//verible/verilog/CST:verilog-nonterminals",
         "//verible/verilog/analysis:descriptions",
         "//verible/verilog/analysis:lint-rule-registry",
+        "@abseil-cpp//absl/status",
         "@abseil-cpp//absl/strings",
+        "@re2",
     ],
     alwayslink = 1,
 )
@@ -1821,6 +1824,7 @@
         "//verible/common/text:symbol",
         "//verible/common/text:syntax-tree-context",
         "//verible/common/text:token-info",
+        "//verible/common/util:container-util",
         "//verible/verilog/CST:port",
         "//verible/verilog/CST:verilog-matchers",
         "//verible/verilog/analysis:descriptions",
diff --git a/verible/verilog/analysis/checkers/generate-label-prefix-rule.cc b/verible/verilog/analysis/checkers/generate-label-prefix-rule.cc
index c8822ce..e678ad5 100644
--- a/verible/verilog/analysis/checkers/generate-label-prefix-rule.cc
+++ b/verible/verilog/analysis/checkers/generate-label-prefix-rule.cc
@@ -14,12 +14,17 @@
 
 #include "verible/verilog/analysis/checkers/generate-label-prefix-rule.h"
 
+#include <memory>
+#include <string>
 #include <string_view>
 
-#include "absl/strings/match.h"
+#include "absl/status/status.h"
+#include "absl/strings/str_cat.h"
+#include "re2/re2.h"
 #include "verible/common/analysis/lint-rule-status.h"
 #include "verible/common/analysis/matcher/bound-symbol-manager.h"
 #include "verible/common/analysis/matcher/matcher.h"
+#include "verible/common/text/config-utils.h"
 #include "verible/common/text/symbol.h"
 #include "verible/common/text/syntax-tree-context.h"
 #include "verible/common/text/token-info.h"
@@ -38,22 +43,36 @@
 // Register the lint rule
 VERILOG_REGISTER_LINT_RULE(GenerateLabelPrefixRule);
 
-static constexpr std::string_view kMessage =
-    "All generate block labels must start with g_ or gen_";
+static constexpr std::string_view kDefaultStyleRegex = "(g_|gen_).*";
 
-// TODO(fangism): and be lower_snake_case?
-// TODO(fangism): generalize to a configurable pattern and
-// rename this class/rule to GenerateLabelNamingStyle?
+GenerateLabelPrefixRule::GenerateLabelPrefixRule()
+    : style_regex_(
+          std::make_unique<re2::RE2>(kDefaultStyleRegex, re2::RE2::Quiet)) {}
 
 const LintRuleDescriptor &GenerateLabelPrefixRule::GetDescriptor() {
   static const LintRuleDescriptor d{
       .name = "generate-label-prefix",
       .topic = "generate-constructs",
-      .desc = "Checks that every generate block label starts with g_ or gen_.",
+      .desc =
+          "Checks that every generate block label matches the regex defined by "
+          "style_regex. The default regex requires labels to start with g_ or "
+          "gen_. Refer to https://github.com/chipsalliance/verible/tree/master/"
+          "verilog/tools/lint#readme for more detail on verible regex "
+          "patterns.",
+      // NOLINTNEXTLINE(misc-include-cleaner)
+      .param = {{"style_regex", std::string(kDefaultStyleRegex),
+                 "A regex used to check generate label style."}},
   };
   return d;
 }
 
+std::string GenerateLabelPrefixRule::CreateViolationMessage() const {
+  return absl::StrCat(
+      "Generate block label does not match the naming convention defined by "
+      "regex pattern: ",
+      style_regex_->pattern());
+}
+
 // Matches begin statements
 static const Matcher &BlockMatcher() {
   static const Matcher matcher(NodekGenerateBlock());
@@ -84,15 +103,24 @@
       }
 
       if (label != nullptr) {
-        if (!(absl::StartsWith(label->text(), "g_") ||
-              absl::StartsWith(label->text(), "gen_"))) {
-          violations_.insert(verible::LintViolation(*label, kMessage, context));
+        if (!RE2::FullMatch(label->text(), *style_regex_)) {
+          violations_.insert(verible::LintViolation(
+              *label, CreateViolationMessage(), context));
         }
       }
     }
   }
 }
 
+// NOLINTNEXTLINE(misc-include-cleaner)
+absl::Status GenerateLabelPrefixRule::Configure(
+    std::string_view configuration) {
+  using verible::config::SetRegex;
+  absl::Status s = verible::ParseNameValues(
+      configuration, {{"style_regex", SetRegex(&style_regex_)}});
+  return s;
+}
+
 verible::LintRuleStatus GenerateLabelPrefixRule::Report() const {
   return verible::LintRuleStatus(violations_, GetDescriptor());
 }
diff --git a/verible/verilog/analysis/checkers/generate-label-prefix-rule.h b/verible/verilog/analysis/checkers/generate-label-prefix-rule.h
index 9090cf3..e18df9c 100644
--- a/verible/verilog/analysis/checkers/generate-label-prefix-rule.h
+++ b/verible/verilog/analysis/checkers/generate-label-prefix-rule.h
@@ -15,8 +15,13 @@
 #ifndef VERIBLE_VERILOG_ANALYSIS_CHECKERS_GENERATE_LABEL_PREFIX_RULE_H_
 #define VERIBLE_VERILOG_ANALYSIS_CHECKERS_GENERATE_LABEL_PREFIX_RULE_H_
 
+#include <memory>
 #include <set>
+#include <string>
+#include <string_view>
 
+#include "absl/status/status.h"
+#include "re2/re2.h"
 #include "verible/common/analysis/lint-rule-status.h"
 #include "verible/common/analysis/syntax-tree-lint-rule.h"
 #include "verible/common/text/symbol.h"
@@ -27,20 +32,28 @@
 namespace analysis {
 
 // GenerateLabelPrefixRule checks that all generate block labels start
-// with g_ or gen_
+// with g_ or gen_ (configurable via style_regex)
 class GenerateLabelPrefixRule : public verible::SyntaxTreeLintRule {
  public:
   using rule_type = verible::SyntaxTreeLintRule;
 
+  GenerateLabelPrefixRule();
+
   static const LintRuleDescriptor &GetDescriptor();
 
+  std::string CreateViolationMessage() const;
+
   void HandleSymbol(const verible::Symbol &symbol,
                     const verible::SyntaxTreeContext &context) final;
 
   verible::LintRuleStatus Report() const final;
 
+  absl::Status Configure(std::string_view configuration) final;
+
  private:
   std::set<verible::LintViolation> violations_;
+
+  std::unique_ptr<re2::RE2> style_regex_;
 };
 
 }  // namespace analysis
diff --git a/verible/verilog/analysis/checkers/generate-label-prefix-rule_test.cc b/verible/verilog/analysis/checkers/generate-label-prefix-rule_test.cc
index b46bfe4..cb43501 100644
--- a/verible/verilog/analysis/checkers/generate-label-prefix-rule_test.cc
+++ b/verible/verilog/analysis/checkers/generate-label-prefix-rule_test.cc
@@ -27,6 +27,7 @@
 namespace {
 
 using verible::LintTestCase;
+using verible::RunConfiguredLintTestCases;
 using verible::RunLintTestCases;
 
 TEST(GenerateLabelPrefixRuleTest, Various) {
@@ -229,6 +230,40 @@
   RunLintTestCases<VerilogAnalyzer, GenerateLabelPrefixRule>(kTestCases);
 }
 
+TEST(GenerateLabelPrefixRuleTest, CustomRegex) {
+  const std::initializer_list<LintTestCase> kTestCases = {
+      {"module m;\n"
+       "generate\n"
+       "if (1) begin : my_custom_label\n"
+       "end\n"
+       "endgenerate\nendmodule\n"},
+      {"module m;\n"
+       "generate\n"
+       "for (genvar i=0; i<5; i++) begin : my_custom_label\n"
+       "end\n"
+       "endgenerate\nendmodule\n"},
+  };
+  RunConfiguredLintTestCases<VerilogAnalyzer, GenerateLabelPrefixRule>(
+      kTestCases, "style_regex:my_.*");
+
+  const std::initializer_list<LintTestCase> kFailCases = {
+      {"module m;\n"
+       "generate\n"
+       "if (1) begin : ",
+       {SymbolIdentifier, "g_label"},
+       "\nend\n"
+       "endgenerate\nendmodule\n"},
+      {"module m;\n"
+       "generate\n"
+       "if (1) begin : ",
+       {SymbolIdentifier, "gen_label"},
+       "\nend\n"
+       "endgenerate\nendmodule\n"},
+  };
+  RunConfiguredLintTestCases<VerilogAnalyzer, GenerateLabelPrefixRule>(
+      kFailCases, "style_regex:my_.*");
+}
+
 }  // namespace
 }  // namespace analysis
 }  // namespace verilog
diff --git a/verible/verilog/analysis/checkers/port-name-suffix-rule.cc b/verible/verilog/analysis/checkers/port-name-suffix-rule.cc
index 85a0db3..ffecef3 100644
--- a/verible/verilog/analysis/checkers/port-name-suffix-rule.cc
+++ b/verible/verilog/analysis/checkers/port-name-suffix-rule.cc
@@ -28,6 +28,7 @@
 #include "verible/common/text/symbol.h"
 #include "verible/common/text/syntax-tree-context.h"
 #include "verible/common/text/token-info.h"
+#include "verible/common/util/container-util.h"
 #include "verible/verilog/CST/port.h"
 #include "verible/verilog/CST/verilog-matchers.h"
 #include "verible/verilog/analysis/descriptions.h"
@@ -90,10 +91,16 @@
        {"output", {"o", "no", "po"}},
        {"inout", {"io", "nio", "pio"}}};
 
-  // At this point it is guaranteed that the direction will be set to
-  // one of the expected values (used as keys in the map above).
-  // Therefore checking the suffix like this is safe
-  return suffixes.at(direction).count(suffix) == 1;
+  // `direction` is usually one of the map keys, but the grammar also permits a
+  // `ref` port direction, which has no suffix convention. FindWithDefault looks
+  // the direction up with an empty-set fallback, so an unknown direction (e.g.
+  // `ref`) has no required suffixes and is treated as "correct" (no violation),
+  // consistent with Violation() which also ignores non-input/output/inout
+  // directions.
+  static const std::set<std::string_view> kNoConvention;
+  const std::set<std::string_view> &valid =
+      verible::container::FindWithDefault(suffixes, direction, kNoConvention);
+  return valid.empty() || valid.count(suffix) == 1;
 }
 
 void PortNameSuffixRule::HandleSymbol(const Symbol &symbol,
@@ -113,8 +120,11 @@
         absl::StrSplit(name, '_', absl::SkipEmpty());
 
     if (name_parts.size() < 2) {
-      // No suffix at all
+      // No suffix at all. This also covers an all-underscore name (e.g. "_"),
+      // for which SkipEmpty leaves name_parts empty; return here so the
+      // name_parts.back() access below is not reached on an empty vector.
       Violation(direction, token, context);
+      return;
     }
 
     if (!IsSuffixCorrect(name_parts.back(), direction)) {
diff --git a/verible/verilog/analysis/checkers/port-name-suffix-rule_test.cc b/verible/verilog/analysis/checkers/port-name-suffix-rule_test.cc
index 69f18f4..db69d71 100644
--- a/verible/verilog/analysis/checkers/port-name-suffix-rule_test.cc
+++ b/verible/verilog/analysis/checkers/port-name-suffix-rule_test.cc
@@ -57,6 +57,9 @@
       {"module t (input bit name_i); endmodule;"},
       {"module t (output bit abc_o); endmodule;"},
       {"module t (inout bit xyz_io); endmodule;"},
+      // A `ref` port has no suffix convention and must not be flagged (and must
+      // not crash the rule via std::map::at).
+      {"module t (ref logic data_x); endmodule;"},
       {"module t (input logic name_i,\n"
        "output logic abc_o,\n"
        "inout logic xyz_io,\n"
@@ -90,6 +93,10 @@
       {"module t (output logic ", {kToken, "_o"}, "); endmodule;"},
       {"module t (inout logic ", {kToken, "_io"}, "); endmodule;"},
 
+      // An all-underscore name splits (SkipEmpty) to an empty parts list; it
+      // must report a suffix violation, not dereference an empty vector.
+      {"module t (input logic ", {kToken, "_"}, "); endmodule;"},
+
       {"module t (input logic ", {kToken, "namei"}, "); endmodule;"},
       {"module t (input logic ", {kToken, "nam_ei"}, "); endmodule;"},
       {"module t (input logic ", {kToken, "name_o"}, "); endmodule;"},
diff --git a/verible/verilog/analysis/verilog-equivalence.cc b/verible/verilog/analysis/verilog-equivalence.cc
index f8a47d0..68c8c98 100644
--- a/verible/verilog/analysis/verilog-equivalence.cc
+++ b/verible/verilog/analysis/verilog-equivalence.cc
@@ -89,6 +89,20 @@
   return IsUnlexed(verilog_tokentype(token.token_enum()));
 }
 
+// MacroIdentifier vs MacroIdItem depends only on whether the macro ends the
+// line (see POST_MACRO_ID in verilog.lex). Spelling-equal macros are
+// format-equivalent across that reclassification.
+static bool AreSpellingEqualLineEndingMacros(const TokenInfo &left,
+                                             const TokenInfo &right) {
+  const auto is_line_ending_macro = [](int token_enum) {
+    return token_enum == verilog_tokentype::MacroIdentifier ||
+           token_enum == verilog_tokentype::MacroIdItem;
+  };
+  return is_line_ending_macro(left.token_enum()) &&
+         is_line_ending_macro(right.token_enum()) &&
+         left.text() == right.text();
+}
+
 DiffStatus VerilogLexicallyEquivalent(
     std::string_view left, std::string_view right,
     const std::function<bool(const verible::TokenInfo &)> &remove_predicate,
@@ -167,11 +181,17 @@
   DiffStatus diff_status = DiffStatus::kEquivalent;
   auto recursive_comparator = [&](const TokenSequence::const_iterator l,
                                   const TokenSequence::const_iterator r) {
+    // Some token enums differ only by surrounding whitespace (e.g. whether a
+    // macro or ')' ends a line). Treat those pairs as matching enums when the
+    // spelling is unchanged so FormatEquivalent tolerates re-wrapping.
+    const bool whitespace_dependent_macro_enum_match =
+        ((l->token_enum() == verilog_tokentype::MacroCallCloseToEndLine &&
+          r->text() == ")") ||
+         (r->token_enum() == verilog_tokentype::MacroCallCloseToEndLine &&
+          l->text() == ")") ||
+         AreSpellingEqualLineEndingMacros(*l, *r));
     if (l->token_enum() != r->token_enum() &&
-        !((l->token_enum() == verilog_tokentype::MacroCallCloseToEndLine &&
-           r->text() == ")") ||
-          (r->token_enum() == verilog_tokentype::MacroCallCloseToEndLine &&
-           l->text() == ")"))) {
+        !whitespace_dependent_macro_enum_match) {
       if (errstream != nullptr) {
         *errstream << "Mismatched token enums.  got: ";
         token_printer(*l, *errstream);
@@ -258,6 +278,9 @@
              (r.text() == ")"))) {
           return true;
         }
+        if (AreSpellingEqualLineEndingMacros(l, r)) {
+          return true;
+        }
         return l.EquivalentWithoutLocation(r);
       },
       errstream);
diff --git a/verible/verilog/analysis/verilog-equivalence_test.cc b/verible/verilog/analysis/verilog-equivalence_test.cc
index 90b0ee1..1cb9436 100644
--- a/verible/verilog/analysis/verilog-equivalence_test.cc
+++ b/verible/verilog/analysis/verilog-equivalence_test.cc
@@ -255,6 +255,21 @@
   }
 }
 
+// MacroIdentifier vs MacroIdItem depends on whether the macro ends the line.
+TEST(FormatEquivalentTest, EquivalenceOfMacroIdentifierAndMacroIdItem) {
+  const char *kSameSpelling[] = {
+      "assign x = f(`TOKEN);\n",
+      "assign x = f(\n`TOKEN\n);\n",
+  };
+  ExpectCompareWithErrstream(FormatEquivalent, DiffStatus::kEquivalent,
+                             kSameSpelling[0], kSameSpelling[1]);
+
+  // Different macro names remain different.
+  ExpectCompareWithErrstream(FormatEquivalent, DiffStatus::kDifferent,
+                             "assign x = f(`TOKEN);\n",
+                             "assign x = f(`OTHER);\n");
+}
+
 TEST(FormatEquivalentTest, DiagnosticMismatch) {
   const char *kTestCases[] = {
       "module foo;\n",
diff --git a/verible/verilog/formatting/format-style-init.cc b/verible/verilog/formatting/format-style-init.cc
index 2dde818..a6d010b 100644
--- a/verible/verilog/formatting/format-style-init.cc
+++ b/verible/verilog/formatting/format-style-init.cc
@@ -140,6 +140,13 @@
           "Use compact binary expressions inside indexing / bit selection "
           "operators");
 
+ABSL_FLAG(bool, class_parameter_space, false,
+          "If true, keep/insert a space before '#' in a class"
+          "parameterized typedef, e.g. \"typedef my_class #(.P(P)) "
+          "my_class_t;\".  If false (default), no space is inserted, "
+          "matching the convention used for IEEE parameterized class "
+          "instantiations, e.g. \"type#(params...)::method(...)\".");
+
 ABSL_FLAG(bool, wrap_end_else_clauses, false,
           "Split end and else keywords into separate lines");
 
@@ -197,6 +204,7 @@
   STYLE_FROM_FLAG(try_wrap_long_lines);
   STYLE_FROM_FLAG(expand_coverpoints);
   STYLE_FROM_FLAG(compact_indexing_and_selections);
+  STYLE_FROM_FLAG(class_parameter_space);
   STYLE_FROM_FLAG(wrap_end_else_clauses);
   STYLE_FROM_FLAG(alignment_group_boundary);
 
diff --git a/verible/verilog/formatting/format-style.h b/verible/verilog/formatting/format-style.h
index 2fad329..55347c5 100644
--- a/verible/verilog/formatting/format-style.h
+++ b/verible/verilog/formatting/format-style.h
@@ -146,6 +146,9 @@
   // Compact binary expressions inside indexing / bit selection operators
   bool compact_indexing_and_selections = true;
 
+  // Keep/insert a space before '#' in a parameterized class typedef
+  bool class_parameter_space = false;
+
   // Split with a \n end and else clauses
   bool wrap_end_else_clauses = false;
 
diff --git a/verible/verilog/formatting/formatter_test.cc b/verible/verilog/formatting/formatter_test.cc
index 5205a01..13a9fb4 100644
--- a/verible/verilog/formatting/formatter_test.cc
+++ b/verible/verilog/formatting/formatter_test.cc
@@ -4478,19 +4478,42 @@
      "    .L(L),\n"
      "    .W(W)\n"
      ") bar_t;\n"},
-    // unqualified parameterized type keeps a space before '#'
+    // By default (class_parameter_space == false), no space before '#'
     {"typedef dv_base_env_cov #(.CFG_T(tl_agent_env_cfg)) tl_agent_env_cov;\n",
-     "typedef dv_base_env_cov #(\n"
+     "typedef dv_base_env_cov#(\n"
      "    .CFG_T(tl_agent_env_cfg)\n"
      ") tl_agent_env_cov;\n"},
-    // ... and is inserted when absent
     {"typedef dv_base_env_cov#(.CFG_T(tl_agent_env_cfg)) tl_agent_env_cov;\n",
-     "typedef dv_base_env_cov #(\n"
+     "typedef dv_base_env_cov#(\n"
      "    .CFG_T(tl_agent_env_cfg)\n"
      ") tl_agent_env_cov;\n"},
     // single short parameter stays on one line
     {"typedef my_class #(.P(P)) my_class_t;\n",
-     "typedef my_class #(.P(P)) my_class_t;\n"},
+     "typedef my_class#(.P(P)) my_class_t;\n"},
+
+    // let declarations each stay on their own line
+    {"module t;\n"
+     "let OFF = 4;\n"
+     "let UNIQUE = 32;\n"
+     "let PP(a) = 30 + a;\n"
+     "endmodule\n",
+     "module t;\n"
+     "  let OFF = 4;\n"
+     "  let UNIQUE = 32;\n"
+     "  let PP(a) = 30 + a;\n"
+     "endmodule\n"},
+
+    // let declarations each stay on their own line
+    {"module t;\n"
+     "let OFF = 4;\n"
+     "let UNIQUE = 32;\n"
+     "let PP(a) = 30 + a;\n"
+     "endmodule\n",
+     "module t;\n"
+     "  let OFF = 4;\n"
+     "  let UNIQUE = 32;\n"
+     "  let PP(a) = 30 + a;\n"
+     "endmodule\n"},
 
     // package test cases
     {"package fedex;localparam  int  www=3 ;endpackage   :  fedex\n",
@@ -4707,6 +4730,15 @@
      "  for (int i = 0; i < f(m); i--) begin\n"
      "  end\n"
      "endfunction\n"},
+    {// for loop with an attribute instance in the initializer.
+     // Regression: this used to abort with a CHECK failure while reshaping
+     // the kForSpec partitions when an attribute appears in the header.
+     "module m; initial for(int i=0(* a *);i<4;i++) x=i; endmodule",
+     "module m;\n"
+     "  initial\n"
+     "    for (int i = 0 (* a *); i < 4; i++)\n"
+     "      x = i;\n"
+     "endmodule\n"},
     {// forever loop
      "function\nvoid\tforevah;forever  begin "
      "++k\n;end endfunction\n",
@@ -18788,6 +18820,50 @@
   }
 }
 
+static constexpr FormatterTestCase
+    kSpaceBeforeHashInUnqualifiedTypedefTestCases[] = {
+        // unqualified parameterized type keeps a space before '#'
+        {"typedef dv_base_env_cov #(.CFG_T(tl_agent_env_cfg)) "
+         "tl_agent_env_cov;\n",
+         "typedef dv_base_env_cov #(\n"
+         "    .CFG_T(tl_agent_env_cfg)\n"
+         ") tl_agent_env_cov;\n"},
+        // ... and is inserted when absent
+        {"typedef dv_base_env_cov#(.CFG_T(tl_agent_env_cfg)) "
+         "tl_agent_env_cov;\n",
+         "typedef dv_base_env_cov #(\n"
+         "    .CFG_T(tl_agent_env_cfg)\n"
+         ") tl_agent_env_cov;\n"},
+        // single short parameter stays on one line
+        {"typedef my_class #(.P(P)) my_class_t;\n",
+         "typedef my_class #(.P(P)) my_class_t;\n"},
+        // package-qualified types are unaffected (no space before '#')
+        {"typedef foo_pkg::baz_t#(.L(L), .W(W)) bar_t;\n",
+         "typedef foo_pkg::baz_t#(\n"
+         "    .L(L),\n"
+         "    .W(W)\n"
+         ") bar_t;\n"},
+};
+
+TEST(FormatterEndToEndTest, SpaceBeforeHashInUnqualifiedTypedefTestCases) {
+  // Use a fixed style.
+  FormatStyle style;
+  style.column_limit = 40;
+  style.indentation_spaces = 2;
+  style.wrap_spaces = 4;
+  style.class_parameter_space = true;
+
+  for (const auto &test_case : kSpaceBeforeHashInUnqualifiedTypedefTestCases) {
+    VLOG(1) << "code-to-format:\n" << test_case.input << "<EOF>";
+    std::ostringstream stream;
+    const auto status =
+        FormatVerilog(test_case.input, "<filename>", style, stream);
+    // Require these test cases to be valid.
+    EXPECT_OK(status) << status.message();
+    EXPECT_EQ(stream.str(), test_case.expected) << "code:\n" << test_case.input;
+  }
+}
+
 static constexpr FormatterTestCase kFunctionCallsWithComments[] = {
     {// no comments
      "module foo;\n"
@@ -19380,6 +19456,24 @@
   }
 }
 
+// Regression for https://github.com/chipsalliance/verible/issues/2544:
+// Wrapping a $bits(...)'(...) cast may leave `MACRO at EOL, reclassifying
+// MacroIdentifier as MacroIdItem. FormatEquivalent must accept that, and
+// formatting must still pass verification.
+TEST(FormatterEndToEndTest, MacroBeforeCloseParenFormatEquivalent) {
+  static constexpr std::string_view kInput =
+      "module m;\n"
+      "  assign result_value = $bits(result_value)'( "
+      "compare_bytes(input_data[DATA_WIDTH_INT-1:0], "
+      "input_datak[STROBE_WIDTH_INT-1:0], `TOKEN_BYTE) );\n"
+      "endmodule\n";
+  FormatStyle style;
+  std::ostringstream stream;
+  const auto status = FormatVerilog(kInput, "<filename>", style, stream);
+  EXPECT_OK(status) << status.message();
+  EXPECT_THAT(stream.str(), testing::HasSubstr("`TOKEN_BYTE"));
+}
+
 // Regression for https://github.com/chipsalliance/verible/issues/2542:
 // Continuation EOL comments after a wrapped assign must keep a stable column
 // across re-format (convergence).
diff --git a/verible/verilog/formatting/token-annotator.cc b/verible/verilog/formatting/token-annotator.cc
index def1349..ebaeb21 100644
--- a/verible/verilog/formatting/token-annotator.cc
+++ b/verible/verilog/formatting/token-annotator.cc
@@ -510,7 +510,8 @@
     // This may be controversial or context-dependent, as parameterized
     // classes often appear with method calls like:
     //   type#(params...)::method(...);
-    // A parameterized type in a typedef keeps the space before '#':
+    // If style.class_parameter_space is enabled, a
+    // parameterized type in a typedef keeps the space before '#':
     //   typedef my_class #(.P(P)) my_class_t;
     // but a package-qualified type does not, matching the existing
     // "type#(params...)::method(...)" convention:
@@ -518,6 +519,7 @@
     // Kept as separate IsInsideFirst() calls because MatchesTagAnyOf()
     // only unrolls up to four tags.
     const bool inside_unqualified_typedef =
+        style.class_parameter_space &&
         left_context.IsInsideFirst({NodeEnum::kTypeDeclaration}, {}) &&
         !left_context.IsInsideFirst({NodeEnum::kQualifiedId}, {});
 
diff --git a/verible/verilog/formatting/tree-unwrapper.cc b/verible/verilog/formatting/tree-unwrapper.cc
index a6601ac..2286f8c 100644
--- a/verible/verilog/formatting/tree-unwrapper.cc
+++ b/verible/verilog/formatting/tree-unwrapper.cc
@@ -801,6 +801,7 @@
     case NodeEnum::kPreprocessorUndef:
     case NodeEnum::kTFPortDeclaration:
     case NodeEnum::kTypeDeclaration:
+    case NodeEnum::kLetDeclaration:
     case NodeEnum::kNetTypeDeclaration:
     case NodeEnum::kForwardDeclaration:
     case NodeEnum::kInterfaceClassMethod:
@@ -2990,10 +2991,15 @@
       auto &children = partition.Children();
       const auto iter1 = std::find_if(children.begin(), children.end(),
                                       PartitionStartsWithSemicolon);
-      CHECK(iter1 != children.end());
+      // An attribute instance ((* ... *)) in the for-loop header can change
+      // the partition structure so that the expected semicolon-leading
+      // partitions are not present.  When they are missing, leave the
+      // partitions unreshaped rather than aborting (avoids a CHECK-failure
+      // crash on attributed/unusual for-headers).
+      if (iter1 == children.end()) break;
       const auto iter2 =
           std::find_if(iter1 + 1, children.end(), PartitionStartsWithSemicolon);
-      CHECK(iter2 != children.end());
+      if (iter2 == children.end()) break;
       const int dist1 = std::distance(children.begin(), iter1);
       const int dist2 = std::distance(children.begin(), iter2);
       VLOG(4) << "kForSpec got ';' at child " << dist1 << " and " << dist2;
diff --git a/verible/verilog/tools/formatter/README.md b/verible/verilog/tools/formatter/README.md
index 01b2869..a3ffb45 100644
--- a/verible/verilog/tools/formatter/README.md
+++ b/verible/verilog/tools/formatter/README.md
@@ -42,6 +42,11 @@
       {align,flush-left,preserve,infer}); default: infer;
     --class_member_variable_alignment (Format class member variables:
       {align,flush-left,preserve,infer}); default: infer;
+    --class_parameter_space (If true, keep/insert a space
+      before '#' in a class parameterized typedef, e.g. "typedef
+      my_class #(.P(P)) my_class_t;". If false (default), no space is
+      inserted, matching the IEEE convention used for parameterized class
+      instantiations, e.g. "type#(params...)::method(...)".); default: false;
     --compact_indexing_and_selections (Use compact binary expressions inside
       indexing / bit selection operators); default: true;
     --distribution_items_alignment (Align distribution items: