Handle invalid expressions in .WORD directives with a message.

This is most relevant in implied .WORD directives which are caused by an
attempt to call a macro (which happens to be undefined) with arguments
that don't parse as valid expressions.

assemble_aux.c

@@ -653,9 +653,14 @@ int do_word(
         } else {
             EX_TREE        *value = parse_expr(cp, 0);
 
-            store_value(stack, tr, size, value);
+            if (value->cp > cp) {
+                store_value(stack, tr, size, value);
 
-            cp = value->cp;
+                cp = value->cp;
+            } else {
+                report(stack->top, "Invalid expression in .WORD\n");
+                cp = "";                /* force loop to end */
+            }
 
             free_tree(value);
         }

tests/RunTests

@@ -6,7 +6,18 @@
 # If there is a .objd.ok file, it compares the result of dumpobj.
 #
 
-TESTS="test-asciz test-backpatch test-bsl-mac-arg test-complex-reloc test-endm test-include test-jmp test-locals test-macro-comma test-undef test-word-comma"
+TESTS="test-asciz \
+    test-backpatch \
+    test-bsl-mac-arg \
+    test-complex-reloc \
+    test-endm \
+    test-impword \
+    test-include \
+    test-jmp \
+    test-locals \
+    test-macro-comma \
+    test-undef \
+    test-word-comma"
 
 for t in $TESTS
 do

tests/test-impword.mac

@@ -0,0 +1,12 @@
+;;;;;
+;
+; Test the implied .word construction
+;
+
+start:	3
+	start
+        ; The following could be a macro which by accident is not defined
+        ; which takes arguments that don't parse as expressions.
+	macro	8-BIT,1,2,3
+        ; The following can by accident be parsed as an expression.
+	macro	7-BIT,1,2,3