Fix and test case for Mantis bug 2070

inform7/Tests/Test Problems/PM_LoopWithoutBody.txt

@@ -0,0 +1,16 @@
+Lab is a room.
+
+Explaining is an action out of world applying to one topic.
+Understand "explain [text]" as explaining.
+
+Report explaining:
+	let L be the topic understood;
+	repeat with I running from 1 to the number of rows in the Table of Explanations;
+	choose row I in the Table of Explanations;
+	if there is a subject entry:
+		if L is the subject entry:
+			say "Explanation here."
+
+Table of Explanations
+subject (text)
+"bug"

inform7/Tests/Test Problems/_Results_Ideal/PM_LoopWithoutBody.txt

@@ -0,0 +1,11 @@
+Inform 7 v10.1.0 has started.
+I've now read your source text, which is 73 words long.
+I've also read Basic Inform by Graham Nelson, which is 7691 words long.
+I've also read English Language by Graham Nelson, which is 2328 words long.
+I've also read Standard Rules by Graham Nelson, which is 32092 words long.
+Problem__ PM_LoopWithoutBody
+  >--> You wrote 'repeat with I running from 1 to the number of rows in the
+    Table of Explanations' (source text, line 8): but there doesn't seem to be
+    any body to this phrase, in the way that a 'repeat', 'if' or 'while' is
+    expected to have.
+Inform 7 has finished.

inform7/imperative-module/Chapter 3/Code Blocks.w

@@ -134,7 +134,7 @@ void CodeBlocks::beginning_block_phrase(control_structure_phrase *csp) {
 		CodeBlocks::pop_stack();
 	}
 	CodeBlocks::prepush_stack();
-	@<Construct the next phrase block@>;
+	if (block_being_opened) @<Construct the next phrase block@>;
 }
 
 @ In the case of a repeat through a Table, we need to create two loop
@@ -153,12 +153,16 @@ the loop begins, and pull them again when it finishes.
 @ Slightly later on, we know these:
 
 =
-void CodeBlocks::attach_back_schema(inter_schema *I, csi_state CSIS) {
-	block_being_opened->switch_val = NULL;
-	if (Invocations::get_no_tokens(CSIS.inv) > 0)
-		block_being_opened->switch_val = CSIS.tokens->token_vals[0];
-	block_being_opened->tail_schema = I;
-	block_being_opened->compilation_state = CSIS;
+int CodeBlocks::attach_back_schema(inter_schema *I, csi_state CSIS) {
+	if (block_being_opened) {
+		block_being_opened->switch_val = NULL;
+		if (Invocations::get_no_tokens(CSIS.inv) > 0)
+			block_being_opened->switch_val = CSIS.tokens->token_vals[0];
+		block_being_opened->tail_schema = I;
+		block_being_opened->compilation_state = CSIS;
+		return TRUE;
+	}
+	return FALSE;
 }
 
 @ At this next stage, the preliminary code for the loop (if it's a loop)

inform7/imperative-module/Chapter 5/Compile Invocations Inline.w

@@ -73,10 +73,17 @@ int CSIInline::csi_inline(value_holster *VH, parse_node *inv, source_location *w
 	@<Create any new local variables explicitly called for@>;
 	CSIInline::from_schema(idb->head_of_defn->at,
 		CompileImperativeDefn::get_front_schema(idb), &CSIS);
-	if (IDTypeData::block_follows(idb))
-		CodeBlocks::attach_back_schema(CompileImperativeDefn::get_back_schema(idb), CSIS);
-	else
+	if (IDTypeData::block_follows(idb)) {
+		if (CodeBlocks::attach_back_schema(
+			CompileImperativeDefn::get_back_schema(idb), CSIS) == FALSE) {
+			StandardProblems::sentence_problem(Task::syntax_tree(),
+				_p_(PM_LoopWithoutBody),
+				"there doesn't seem to be any body to this phrase",
+				"in the way that a 'repeat', 'if' or 'while' is expected to have.");
+		}
+	} else {
 		@<Release any my-variables created inline@>;
+	}
 	return idb->compilation_data.inline_mor;
 }