Merge pull request #3657 from Hackerpilot/issue-12888

Issue 12888 - Include template constraints in JSON output

src/json.c

@@ -789,6 +789,12 @@ class ToJsonVisitor : public Visitor
         }
         arrayEnd();
 
+        Expression *expression = d->constraint;
+        if (expression)
+        {
+            property("constraint", expression->toChars());
+        }
+
         propertyStart("members");
         arrayStart();
         for (size_t i = 0; i < d->members->dim; i++)

test/compilable/extra-files/json.out

@@ -565,6 +565,20 @@
       "char" : 5
      }
     ]
+   },
+   {
+    "kind" : "template",
+    "line" : 112,
+    "char" : 1,
+    "name" : "IncludeConstraint",
+    "parameters" : [
+     {
+      "name" : "T",
+      "kind" : "type"
+     }
+    ],
+    "constraint" : "T == string",
+    "members" : []
    }
   ]
  }

test/compilable/json.d

@@ -108,3 +108,5 @@ enum Numbers
     unspecified4,
     four = 4,
 }
+
+template IncludeConstraint(T) if (T == string) {}