Accept a constant expression as an array bound

Source/SimpleParser/SimpleParser.pas

@@ -3648,6 +3648,16 @@ procedure TmwSimplePasPar.OrdinalType;
             begin
               ConstantExpression;
             end;
+          { An operator after the identifier means the bound is a constant
+            expression, not a type name: array[mlab + 1..mlog]. Reading it as a
+            type name consumes the identifier alone and leaves the caller at the
+            operator, where it can only report an error. These are the operators
+            SimpleExpression and Term accept. }
+          ptAnd, ptDiv, ptMinus, ptMod, ptOr, ptPlus, ptShl, ptShr, ptSlash,
+          ptStar, ptXor:
+            begin
+              ConstantExpression;
+            end;
         else
           begin
             TypeID;

Test/Snippets/arrayboundexpression.pas

@@ -0,0 +1,22 @@
+unit arrayboundexpression;
+
+interface
+
+const
+  mlab = 4;
+  mlog = 12;
+
+type
+  { An array bound is a constant EXPRESSION, not just a constant or a type name.
+    OrdinalType decided on one token of lookahead and read `mlab` as a type name,
+    so the whole unit failed to parse at the `+`. }
+  TRanges = record
+    iu: array[mlab + 1..mlog] of Integer;
+    du: array[mlab * 2..mlog - 1, 0..mlab shl 1] of Byte;
+  end;
+
+  TSetOfExpression = set of mlab + 1..mlog;
+
+implementation
+
+end.