Merge pull request #2585 from EylonKrause/fix-forspec-attribute-crash

formatter: avoid crash on attribute instance in for-loop header
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/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..2151eaa 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,
 )
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/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 f9bb19e..bd0f775 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",
@@ -18797,6 +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"
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 c373590..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:
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: