diff --git a/src/V3AstNodes.cpp b/src/V3AstNodes.cpp
index 7f4c57e0e..62596a32d 100644
--- a/src/V3AstNodes.cpp
+++ b/src/V3AstNodes.cpp
@@ -794,7 +794,7 @@ const AstNodeDType* AstNodeDType::skipRefIterp(bool skipConst, bool skipEnum) co
                 nodep = subp;
                 continue;
             } else {
-                v3fatalSrc("Typedef not linked");
+                nodep->v3fatalSrc(nodep->prettyTypeName() << " not linked to type");
                 return nullptr;
             }
         }
diff --git a/src/V3Error.h b/src/V3Error.h
index d0a2bf77f..62cb9af52 100644
--- a/src/V3Error.h
+++ b/src/V3Error.h
@@ -564,9 +564,9 @@ void v3errorEndFatal(std::ostringstream& sstr)
 #define v3info(msg) v3warnCode(V3ErrorCode::EC_INFO, msg)
 #define v3error(msg) v3warnCode(V3ErrorCode::EC_ERROR, msg)
 #define v3fatal(msg) v3warnCodeFatal(V3ErrorCode::EC_FATAL, msg)
-// Use this instead of fatal() if message gets suppressed with --quiet-exit
+// Fatal exit; used instead of fatal() if message gets suppressed with --quiet-exit
 #define v3fatalExit(msg) v3warnCodeFatal(V3ErrorCode::EC_FATALEXIT, msg)
-// Use this instead of fatal() to mention the source code line.
+// Fatal exit; used instead of fatal() to mention the source code line
 #define v3fatalSrc(msg) \
     v3errorEndFatal(v3errorBuildMessage( \
         V3Error::v3errorPrepFileLine(V3ErrorCode::EC_FATALSRC, __FILE__, __LINE__), msg))
@@ -574,6 +574,10 @@ void v3errorEndFatal(std::ostringstream& sstr)
 #define v3fatalStatic(msg) \
     ::v3errorEndFatal(v3errorBuildMessage(V3Error::v3errorPrep(V3ErrorCode::EC_FATAL), msg))
 
+/// Print a message when debug() >= level.  stmsg is stream; e.g. use as '"foo=" << foo'
+//
+// Requires debug() function to exist in current scope, to hack this in temporarily:
+// auto debug = []() -> bool { return V3Error::debugDefault(); };
 #define UINFO(level, stmsg) \
     do { \
         if (VL_UNCOVERABLE(debug() >= (level))) { \
@@ -585,6 +589,7 @@ void v3errorEndFatal(std::ostringstream& sstr)
         if (VL_UNCOVERABLE(debug() >= (level))) { std::cout << stmsg; } \
     } while (false)
 
+/// Compile statements only when debug build
 #ifdef VL_DEBUG
 #define UDEBUGONLY(stmts) \
     do { stmts } while (false)
@@ -595,12 +600,12 @@ void v3errorEndFatal(std::ostringstream& sstr)
     } while (false)
 #endif
 
-// Assertion without object, generally UOBJASSERT preferred
+/// Assert without error location, generally UASSERT_OBJ preferred
 #define UASSERT(condition, stmsg) \
     do { \
         if (VL_UNCOVERABLE(!(condition))) v3fatalSrc(stmsg); \
     } while (false)
-// Assertion with object
+/// Assert with object to provide error location
 #define UASSERT_OBJ(condition, obj, stmsg) \
     do { \
         if (VL_UNCOVERABLE(!(condition))) (obj)->v3fatalSrc(stmsg); \
@@ -614,7 +619,7 @@ void v3errorEndFatal(std::ostringstream& sstr)
             V3Error::vlAbort(); \
         } \
     } while (false)
-// Check self test values for expected value.  Safe from side-effects.
+/// Check self test values for expected value.  Safe from side-effects.
 // Type argument can be removed when go to C++11 (use auto).
 #define UASSERT_SELFTEST(Type, got, exp) \
     do { \
@@ -625,6 +630,7 @@ void v3errorEndFatal(std::ostringstream& sstr)
                             << g << " expected=" << e); \
     } while (false)
 
+// Error that call not supported; only for some Ast functions
 #define V3ERROR_NA \
     do { \
         v3error("Internal: Unexpected Call"); \
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index 304bd4529..95a200463 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -1692,7 +1692,6 @@ public:
     LinkDotFindVisitor(AstNetlist* rootp, LinkDotState* statep)
         : m_statep{statep} {
         UINFO(4, __FUNCTION__ << ": " << endl);
-
         iterate(rootp);
     }
     ~LinkDotFindVisitor() override = default;
@@ -4063,7 +4062,8 @@ class LinkDotResolveVisitor final : public VNVisitor {
                 const AstClass* const clsp = VN_CAST(cpackagerefp->classOrPackageNodep(), Class);
                 if (clsp && clsp->isParameterized()) {
                     // Unable to link before the instantiation of parameter classes.
-                    // The class reference node has to be visited to properly link parameters.
+                    // The class reference node still has to be visited now to later link
+                    // parameters.
                     iterate(cpackagep);
                     return;
                 }