4878 Ddoc: Default arguments can break Ddoc output

(patch by Johannes Pfau)

src/doc.c

@@ -363,6 +363,36 @@ void Module::gendocfile()
 /****************************************************
  * Having unmatched parentheses can hose the output of Ddoc,
  * as the macros depend on properly nested parentheses.
+ * This function replaces all ( with $(LPAREN) and ) with $(RPAREN)
+ * to preserve text literally. This also means macros in the
+ * text won't be expanded.
+ */
+void escapeDdocString(OutBuffer *buf, unsigned start)
+{
+    for (unsigned u = start; u < buf->offset; u++)
+    {
+        unsigned char c = buf->data[u];
+        switch(c)
+        {
+            case '(':
+                buf->remove(u, 1); //remove the (
+                buf->insert(u, "$(LPAREN)", 9); //insert this instead
+                u += 8; //skip over newly inserted macro
+                break;
+
+            case ')':
+                buf->remove(u, 1); //remove the )
+                buf->insert(u, "$(RPAREN)", 9); //insert this instead
+                u += 8; //skip over newly inserted macro
+                break;
+        }
+    }
+}
+
+/****************************************************
+ * Having unmatched parentheses can hose the output of Ddoc,
+ * as the macros depend on properly nested parentheses.
+
  * Fix by replacing unmatched ( with $(LPAREN) and unmatched ) with $(RPAREN).
  */
 void escapeStrayParenthesis(OutBuffer *buf, unsigned start, Loc loc)

src/doc.h

@@ -15,5 +15,6 @@
 #pragma once
 #endif /* __DMC__ */
 
+void escapeDdocString(OutBuffer *buf, unsigned start);
 
 #endif

src/mtype.c

@@ -48,6 +48,7 @@
 #include "import.h"
 #include "aggregate.h"
 #include "hdrgen.h"
+#include "doc.h"
 
 FuncDeclaration *hasThis(Scope *sc);
 
@@ -8116,7 +8117,12 @@ void Parameter::argsToCBuffer(OutBuffer *buf, HdrGenState *hgs, Parameters *argu
             if (arg->defaultArg)
             {
                 argbuf.writestring(" = ");
+                unsigned o = argbuf.offset;
                 arg->defaultArg->toCBuffer(&argbuf, hgs);
+                if (hgs->ddoc)
+                {
+                    escapeDdocString(&argbuf, o);
+                }
             }
             buf->write(&argbuf);
         }