From 1d7d78c6dac770060787a1d46bbb59dcc7d77863 Mon Sep 17 00:00:00 2001
From: Dana Jansens <danakj@orodu.net>
Date: Wed, 26 Mar 2025 15:59:32 -0700
Subject: [PATCH] Add more output in dump for generics, impls (#5190)

---
 toolchain/check/dump.cpp  |  7 +++++++
 toolchain/sem_ir/dump.cpp | 29 ++++++++++++++++++++++++-----
 toolchain/sem_ir/impl.h   |  3 ++-
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/toolchain/check/dump.cpp b/toolchain/check/dump.cpp
index 330251b256c4..3abeea2c0381 100644
--- a/toolchain/check/dump.cpp
+++ b/toolchain/check/dump.cpp
@@ -99,6 +99,13 @@ LLVM_DUMP_METHOD static auto Dump(const Context& context,
 LLVM_DUMP_METHOD static auto Dump(const Context& context, SemIR::ImplId impl_id)
     -> void {
   SemIR::Dump(context.sem_ir(), impl_id);
+  if (impl_id.has_value()) {
+    const auto& impl = context.sem_ir().impls().Get(impl_id);
+    auto loc_id = context.sem_ir().insts().GetLocId(impl.witness_id);
+    llvm::errs() << "witness loc: ";
+    DumpNoNewline(context, loc_id);
+    llvm::errs() << '\n';
+  }
 }
 
 LLVM_DUMP_METHOD static auto Dump(const Context& context,
diff --git a/toolchain/sem_ir/dump.cpp b/toolchain/sem_ir/dump.cpp
index c80be9363c80..5cc8eb3690cc 100644
--- a/toolchain/sem_ir/dump.cpp
+++ b/toolchain/sem_ir/dump.cpp
@@ -19,6 +19,9 @@ static auto DumpNameIfValid(const File& file, NameId name_id) -> void {
 
 static auto DumpNoNewline(const File& file, ConstantId const_id) -> void {
   llvm::errs() << const_id;
+  if (!const_id.has_value()) {
+    return;
+  }
   if (const_id.is_symbolic()) {
     llvm::errs() << ": "
                  << file.constant_values().GetSymbolicConstant(const_id);
@@ -121,18 +124,34 @@ LLVM_DUMP_METHOD auto Dump(const File& file, FunctionId function_id) -> void {
 
 LLVM_DUMP_METHOD auto Dump(const File& file, GenericId generic_id) -> void {
   llvm::errs() << generic_id;
-  if (generic_id.has_value()) {
-    llvm::errs() << ": " << file.generics().Get(generic_id);
+  if (!generic_id.has_value()) {
+    llvm::errs() << '\n';
+    return;
   }
-  llvm::errs() << '\n';
+  llvm::errs() << ": " << file.generics().Get(generic_id) << '\n';
+  Dump(file, file.generics().Get(generic_id).bindings_id);
 }
 
 LLVM_DUMP_METHOD auto Dump(const File& file, ImplId impl_id) -> void {
   llvm::errs() << impl_id;
-  if (impl_id.has_value()) {
-    llvm::errs() << ": " << file.impls().Get(impl_id);
+  if (!impl_id.has_value()) {
+    llvm::errs() << '\n';
+    return;
   }
+
+  const auto& impl = file.impls().Get(impl_id);
+  llvm::errs() << ": " << impl << '\n';
+  llvm::errs() << "  - interface_id: ";
+  DumpNoNewline(file, impl.interface.interface_id);
   llvm::errs() << '\n';
+  llvm::errs() << "  - specific_id: ";
+  DumpNoNewline(file, impl.interface.specific_id);
+  llvm::errs() << '\n';
+  if (impl.interface.specific_id.has_value()) {
+    auto inst_block_id =
+        file.specifics().Get(impl.interface.specific_id).args_id;
+    Dump(file, inst_block_id);
+  }
 }
 
 LLVM_DUMP_METHOD auto Dump(const File& file, InstBlockId inst_block_id)
diff --git a/toolchain/sem_ir/impl.h b/toolchain/sem_ir/impl.h
index 6c006190c043..ed39f488c082 100644
--- a/toolchain/sem_ir/impl.h
+++ b/toolchain/sem_ir/impl.h
@@ -49,7 +49,8 @@ struct Impl : public EntityWithParamsBase,
               public ImplFields,
               public Printable<Impl> {
   auto Print(llvm::raw_ostream& out) const -> void {
-    out << "{self: " << self_id << ", constraint: " << constraint_id << "}";
+    out << "{self: " << self_id << ", constraint: " << constraint_id
+        << ", witness: " << witness_id << "}";
   }
 
   // Determines whether this impl has been fully defined. This is false until we