Handle grammar ambiguity in if condition

Author: tim-dlang

src/cppconv/cppsemantic.d

@@ -2212,6 +2212,13 @@ void handleConflictExpression(Tree tree, ref immutable(Formula)* goodConditionSt
         handleConflictExpression(tree.childs[1], goodConditionStrict,
                 goodCondition, semantic, ConflictExpressionFlags.none);
     }
+    else if (tree.nonterminalID == nonterminalIDFor!"Condition")
+    {
+        handleConflictExpression(tree.childs[0], goodConditionStrict,
+                goodCondition, semantic, ConflictExpressionFlags.inType);
+        handleConflictExpression(tree.childs[1], goodConditionStrict,
+                goodCondition, semantic, ConflictExpressionFlags.none);
+    }
     else if (tree.nonterminalID == nonterminalIDFor!"DeclSpecifierSeq")
     {
         handleConflictExpression(tree.childs[0], goodConditionStrict,

src/cppconv/cppsemantic1.d

@@ -213,7 +213,8 @@ void runSemantic(ref SemanticRunInfo semantic, ref Tree tree, Tree parent,
                 || tree.name.endsWith("StaticAssertDeclarationX")
                 || tree.name.endsWith("Statement")
                 || tree.nonterminalID == nonterminalIDFor!"TemplateArgumentList"
-                || tree.nonterminalID == nonterminalIDFor!"InitializerList";
+                || tree.nonterminalID == nonterminalIDFor!"InitializerList"
+                || tree.nonterminalID == nonterminalIDFor!"Condition";
         }())
     {
         immutable(Formula)* goodConditionStrict = condition;

src/cppconv/dwriter/treecode.d

@@ -963,14 +963,34 @@ void parseTreeToDCode(T)(ref CodeWriter code, DWriterData data, T tree, immutabl
     {
         auto codeWrapper = ConditionalCodeWrapper(condition, data);
 
-        codeWrapper.checkTree(tree.childs, false);
+        bool shouldDescent(Tree tree)
+        {
+            if (tree.nonterminalID == nonterminalIDFor!"IfStatementHead"
+                && tree.childs[2].nodeType == NodeType.merged)
+            {
+                auto mdata = &semantic.mergedTreeData(tree.childs[2]);
+                foreach (i, c; tree.childs[2].childs)
+                    if (c.nonterminalID == nonterminalIDFor!"Condition"
+                        && !mdata.conditions[i].isFalse)
+                        return true;
+            }
+            return false;
+        }
+
+        codeWrapper.checkTree(tree.childs, false, &shouldDescent);
 
         if (codeWrapper.alwaysUseMixin)
         {
             codeWrapper.begin(code, condition);
 
             void onTree(Tree t, immutable(Formula)* condition2)
             {
+                if (shouldDescent(t))
+                {
+                    foreach (c; t.childs)
+                        codeWrapper.writeTree(code, &onTree, c, condition2);
+                    return;
+                }
                 parseTreeToDCode(code, data, t, condition2, currentScope);
                 writeComments(code, data, data.sourceTokenManager.collectTokens(t.location.end));
                 writeComments(code, data,

tests/single/test389.cpp

@@ -0,0 +1,9 @@
+class C
+{
+};
+C *createC();
+void f()
+{
+    if (C *x = createC())
+    {}
+}

tests/single/test389.d

@@ -0,0 +1,15 @@
+module test389;
+
+import config;
+import cppconvhelpers;
+
+extern(C++, class) struct C
+{
+}
+C* createC();
+void f()
+{
+    if (C* x = createC())
+    {}
+}
+

tests/single/testconflict_md_s_1.cpp

@@ -0,0 +1,24 @@
+#ifdef DEF
+class a
+{
+};
+a *c;
+#else
+struct S
+{
+    S &operator *(S)
+    {
+        return *this;
+    }
+    explicit operator bool() const
+    {
+        return true;
+    }
+};
+S a, b, c;
+#endif
+void f()
+{
+    if (a *b = c)
+    {}
+}

tests/single/testconflict_md_s_1.d

@@ -0,0 +1,46 @@
+module testconflict_md_s_1;
+
+import config;
+import cppconvhelpers;
+
+static if (defined!"DEF")
+{
+extern(C++, class) struct a
+{
+}
+__gshared a* c;
+}
+static if (!defined!"DEF")
+{
+struct S
+{
+    ref S opBinary(string op)(S) if (op == "*")
+    {
+        return this;
+    }
+    /+ explicit +/ auto opCast(T : bool)() const
+    {
+        return true;
+    }
+}
+__gshared S a;
+ __gshared S b;
+  __gshared S c;
+}
+void f()
+{
+    mixin(q{if (
+    }
+    ~ (!defined!"DEF" ? q{
+    (){return a *.b = c;
+    }()
+    }:"")
+    ~ (defined!"DEF" ? q{
+    a* b__1=c
+    }:"")
+    ~ q{
+    )
+        {}
+}
+);}
+