diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index f8cc1ce36..a7d6e53b0 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -3647,7 +3647,11 @@ void DerivationGoal::registerOutputs()
         /* Apply hash rewriting if necessary. */
         bool rewritten = false;
         if (!outputRewrites.empty()) {
-            printError("warning: rewriting hashes in '%1%'; cross fingers", path);
+            logWarning(
+                ErrorInfo {
+                    .name = "Rewriting hashes", 
+                    .hint = hintfmt("rewriting hashes in '%1%'; cross fingers", path)
+                    });
 
             /* Canonicalise first.  This ensures that the path we're
                rewriting doesn't contain a hard link to /etc/shadow or
@@ -4414,8 +4418,12 @@ void SubstitutionGoal::tryNext()
         && !sub->isTrusted
         && !info->checkSignatures(worker.store, worker.store.getPublicKeys()))
     {
-        printError("warning: substituter '%s' does not have a valid signature for path '%s'",
-            sub->getUri(), worker.store.printStorePath(storePath));
+        logWarning(
+            ErrorInfo {
+                .name = "Invalid path signature", 
+                .hint = hintfmt("substituter '%s' does not have a valid signature for path '%s'",
+            sub->getUri(), worker.store.printStorePath(storePath))
+            });
         tryNext();
         return;
     }
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 542e5c552..d1281d130 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -769,7 +769,11 @@ void ValidPathInfo::sign(const Store & store, const SecretKey & secretKey)
 bool ValidPathInfo::isContentAddressed(const Store & store) const
 {
     auto warn = [&]() {
-        printError("warning: path '%s' claims to be content-addressed but isn't", store.printStorePath(path));
+        logWarning(
+            ErrorInfo{
+                .name = "Path not content-addressed", 
+                .hint = hintfmt("path '%s' claims to be content-addressed but isn't", store.printStorePath(path))
+            });
     };
 
     if (hasPrefix(ca, "text:")) {
diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index ce5dde6c3..e4f45a2d3 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -161,7 +161,7 @@ std::ostream& operator<<(std::ostream &out, const ErrorInfo &einfo)
             einfo.programName.value_or(""))
             << std::endl;
 
-    // filename.
+    // filename, line, column.
     if (einfo.nixCode.has_value()) {
         if (einfo.nixCode->errPos.file != "") {
             out << fmt("%1%in file: " ANSI_BLUE "%2% %3%" ANSI_NORMAL,
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 8201549fd..35f7ee917 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -52,7 +52,10 @@ size_t threshold = 256 * 1024 * 1024;
 
 static void warnLargeDump()
 {
-    printError("warning: dumping very large path (> 256 MiB); this may run out of memory");
+    logWarning(ErrorInfo {
+        .name = "Large path",
+        .description = "dumping very large path (> 256 MiB); this may run out of memory"
+        });
 }
 
 
diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 3c2f4f00c..03200d050 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -368,9 +368,12 @@ static void _main(int argc, char * * argv)
                 shell = drv->queryOutPath() + "/bin/bash";
 
             } catch (Error & e) {
-                // TODO: append error msg; warn()?
-                logError(e.info());
-                printError("warning: %s; will use bash from your environment", e.what());
+                logWarning(
+                    ErrorInfo {
+                        .name = "bashInteractive",
+                        .hint = hintfmt("%s; will use bash from your environment", 
+                            (e.info().hint ? e.info().hint->str() : ""))
+                    });
                 shell = "bash";
             }
         }
diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index 57063d42f..9b5cceccf 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -704,7 +704,10 @@ static void opVerify(Strings opFlags, Strings opArgs)
         else throw UsageError("unknown flag '%1%'", i);
 
     if (store->verifyStore(checkContents, repair)) {
-        printError("warning: not all errors were fixed");
+        logWarning(ErrorInfo { 
+            .name = "Store consistency",
+            .description = "not all errors were fixed"
+            });
         throw Exit(1);
     }
 }