Stmt: Error on deprecated when/local usage

This has been around since Zeek v4.1, so it was warned about in Zeek 5.0
LTS and we could've removed it with 5.1.

Also removed merge_top_scope() from the zeek::detail namespace, it's
unused now.

Updated the when-aggregates test somehow. I'm not quite sure what had
been tested there :-/

src/Scope.cc

@@ -190,20 +190,6 @@ ScopePtr pop_scope()
 	return old_top;
 	}
 
-void merge_top_scope()
-	{
-	if ( scopes.size() < 2 )
-		reporter->InternalError("scope merge underflow");
-
-	auto t = pop_scope();
-
-	for ( const auto& v : t->OrderedVars() )
-		{
-		v->SetOffset(top_scope->Length());
-		top_scope->Insert(v->Name(), v);
-		}
-	}
-
 ScopePtr current_scope()
 	{
 	return top_scope;

src/Scope.h

@@ -93,10 +93,6 @@ extern void push_existing_scope(ScopePtr scope);
 // Returns the one popped off.
 extern ScopePtr pop_scope();
 
-// Merges the elements of the current scope with the one surrounding it,
-// popping it in the process.
-extern void merge_top_scope();
-
 extern ScopePtr current_scope();
 extern ScopePtr global_scope();
 

src/Stmt.cc

@@ -1933,11 +1933,10 @@ WhenInfo::WhenInfo(bool arg_is_return) : is_return(arg_is_return)
 
 void WhenInfo::Build(StmtPtr ws)
 	{
+	// This will call ws->Error() if it's deprecated and we can
+	// short-circuit.
 	if ( IsDeprecatedSemantics(ws) )
-		{
-		merge_top_scope();
 		return;
-		}
 
 	if ( ! cl )
 		{
@@ -2095,9 +2094,9 @@ bool WhenInfo::IsDeprecatedSemantics(StmtPtr ws)
 		}
 
 	std::string msg = util::fmt("\"when\" statement referring to locals without an "
-	                            "explicit [] capture is deprecated: %s",
+	                            "explicit [] capture: %s",
 	                            vars.c_str());
-	ws->Warn(msg.c_str());
+	ws->Error(msg.c_str());
 
 	return true;
 	}

src/Stmt.h

@@ -606,9 +606,8 @@ public:
 
 private:
 	// True if the "when" statement corresponds to old-style deprecated
-	// semantics (no captures, but needing captures).  Also generates
+	// semantics (no captures, but needing captures).  Also triggers
-	// the corresponding deprecation warnings, which are associated
+	// an error associated with "ws".
-	// with "ws".
 	bool IsDeprecatedSemantics(StmtPtr ws);
 
 	// Build those elements we'll need for invoking our lambda.

testing/btest/Baseline/language.when-aggregates/zeek..stdout

@@ -1,5 +1,5 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 [x=1, y=2], [x=11, y=12]
 [x=1, y=55], [x=11, y=12]
-[x=111, y=222], [x=13, y=14]
+[x=99, y=222], [x=13, y=14]
 [x=99, y=222], [x=13, y=14]

testing/btest/Baseline/language.when-capture-errors/out

@@ -1,7 +1,7 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-warning in <...>/when-capture-errors.zeek, lines 19-22: "when" statement referring to locals without an explicit [] capture is deprecated: orig1 (when (0 < g) { print orig1})
+error in <...>/when-capture-errors.zeek, lines 19-22: "when" statement referring to locals without an explicit [] capture: orig1 (when (0 < g) { print orig1})
-warning in <...>/when-capture-errors.zeek, lines 25-28: "when" statement referring to locals without an explicit [] capture is deprecated: orig3 (when (0 < g || orig3) { print g})
+error in <...>/when-capture-errors.zeek, lines 25-28: orig3 is used inside "when" statement but not captured (when (0 < g || orig3) { print g})
-warning in <...>/when-capture-errors.zeek, lines 34-38: "when" statement referring to locals without an explicit [] capture is deprecated: orig1 (when (0 < g) { print g} timeout 1.0 sec { print orig1})
+error in <...>/when-capture-errors.zeek, lines 34-38: orig1 is used inside "when" statement but not captured (when (0 < g) { print g} timeout 1.0 sec { print orig1})
 error in <...>/when-capture-errors.zeek, lines 66-70: orig2 is used inside "when" statement but not captured (when (0 < g) { print orig1} timeout 1.0 sec { print orig2})
 error in <...>/when-capture-errors.zeek, lines 76-80: orig3 is captured but not used inside "when" statement (when (0 < g) { print orig1} timeout 1.0 sec { print orig2})
 error in <...>/when-capture-errors.zeek, line 83: no such local identifier: l1

testing/btest/broker/store/clone.zeek

@@ -18,7 +18,7 @@ global h: opaque of Broker::Store;
 
 function print_index(k: any)
         {
-        when ( local r = Broker::get(h, k) )
+        when [k] ( local r = Broker::get(h, k) )
                 {
                 print "master", k, r$status, r$result;
                 }
@@ -88,7 +88,7 @@ global inserted: event();
 
 function print_index(k: any)
         {
-        when ( local r = Broker::get(h, k) )
+        when [k] ( local r = Broker::get(h, k) )
                 {
                 print "clone", k, r$status, r$result;
                 }

testing/btest/language/when-aggregates.zeek

@@ -8,7 +8,7 @@ global g = 0;
 
 function async_foo1(arg: r) : r
 	{
-	return when ( g > 0 )
+	return when [copy arg] ( g > 0 )
 		{
 		arg$x = 99;
 		return r($x = 11, $y = 12);
@@ -29,7 +29,7 @@ event zeek_init()
 	local orig1 = r($x = 1, $y = 2);
 	local orig2 = copy(orig1);
 
-	when ( g == 1 && local resp1 = async_foo1(orig1) )
+	when [copy orig1] ( g == 1 && local resp1 = async_foo1(orig1) )
 		{
 		++g;
 		print orig1, resp1;
@@ -41,10 +41,12 @@ event zeek_init()
 		print orig2, resp2;
 		}
 
+	# The when within async_foo2 does not copy, so orig3 and orig4
+	# within the when body are modified with.
 	local orig3 = r($x = 111, $y = 222);
 	local orig4 = copy(orig3);
 
-	when ( g == 3 && local resp4 = async_foo2(orig3) )
+	when [copy orig3] ( g == 3 && local resp4 = async_foo2(orig3) )
 		{
 		++g;
 		print orig3, resp4;

testing/btest/scripts/base/frameworks/sumstats/on-demand-cluster.zeek

@@ -43,7 +43,7 @@ global ready_for_data: event();
 event on_demand()
 	{
 	local host = 7.2.1.5;
-	when ( local result = SumStats::request_key("test sumstat", [$host=host]) )
+	when [host] ( local result = SumStats::request_key("test sumstat", [$host=host]) )
 		{
 		print "SumStat key request";
 		if ( "test" in result )