Issue 11930 - Alias this not considered in is(T unused: U) matching

dlang · Jan 15, 2014 · a58b373 · a58b373
1 parent 786ea82
commit a58b373
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Showing 3 changed files with 53 additions and 59 deletions.
diff --git a/src/mtype.h b/src/mtype.h
@@ -851,7 +851,6 @@ class TypeStruct : public Type
     bool needsNested();
     dt_t **toDt(dt_t **pdt);
     MATCH deduceType(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm = NULL);
-    MATCH deduceTypeNoRecursion(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm);
     TypeInfoDeclaration *getTypeInfoDeclaration();
     int hasPointers();
     TypeTuple *toArgTypes();
@@ -981,7 +980,6 @@ class TypeClass : public Type
     Expression *defaultInit(Loc loc);
     int isZeroInit(Loc loc);
     MATCH deduceType(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm = NULL);
-    MATCH deduceTypeNoRecursion(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm);
     int isscope();
     int checkBoolean();
     TypeInfoDeclaration *getTypeInfoDeclaration();

diff --git a/src/template.c b/src/template.c
@@ -3389,9 +3389,26 @@ MATCH Type::deduceType(Scope *sc, Type *tparam, TemplateParameters *parameters,
         MATCH m = implicitConvTo(tparam);
         if (m == MATCHnomatch)
         {
-            Type *at = aliasthisOf();
-            if (at)
-                m = at->deduceType(sc, tparam, parameters, dedtypes, wm);
+            if (ty == Tclass)
+            {
+                TypeClass *tc = (TypeClass *)this;
+                if (tc->sym->aliasthis && !(tc->att & RECtracingDT))
+                {
+                    tc->att = (AliasThisRec)(tc->att | RECtracingDT);
+                    m = aliasthisOf()->deduceType(sc, tparam, parameters, dedtypes, wm);
+                    tc->att = (AliasThisRec)(tc->att & ~RECtracingDT);
+                }
+            }
+            else if (ty == Tstruct)
+            {
+                TypeStruct *ts = (TypeStruct *)this;
+                if (ts->sym->aliasthis && !(ts->att & RECtracingDT))
+                {
+                    ts->att = (AliasThisRec)(ts->att | RECtracingDT);
+                    m = aliasthisOf()->deduceType(sc, tparam, parameters, dedtypes, wm);
+                    ts->att = (AliasThisRec)(ts->att & ~RECtracingDT);
+                }
+            }
         }
         return m;
     }
@@ -3875,26 +3892,6 @@ MATCH TypeInstance::deduceType(Scope *sc,
 }
 
 MATCH TypeStruct::deduceType(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm)
-{
-    MATCH m;
-    if (sym->aliasthis)
-    {
-        if (att & RECtracingDT)
-            m = MATCHnomatch;
-        else
-        {
-            att = (AliasThisRec)(att | RECtracingDT);
-            m = deduceTypeNoRecursion(sc, tparam, parameters, dedtypes, wm);
-            att = (AliasThisRec)(att & ~RECtracingDT);
-        }
-    }
-    else
-        m = deduceTypeNoRecursion(sc, tparam, parameters, dedtypes, wm);
-
-    return m;
-}
-
-MATCH TypeStruct::deduceTypeNoRecursion(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm)
 {
     //printf("TypeStruct::deduceType()\n");
     //printf("\tthis->parent   = %s, ", sym->parent->toChars()); print();
@@ -4040,26 +4037,6 @@ void deduceBaseClassParameters(BaseClass *b,
 }
 
 MATCH TypeClass::deduceType(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm)
-{
-    MATCH m;
-    if (sym->aliasthis)
-    {
-        if (att & RECtracingDT)
-            m = MATCHnomatch;
-        else
-        {
-            att = (AliasThisRec)(att | RECtracingDT);
-            m = deduceTypeNoRecursion(sc, tparam, parameters, dedtypes, wm);
-            att = (AliasThisRec)(att & ~RECtracingDT);
-        }
-    }
-    else
-        m = deduceTypeNoRecursion(sc, tparam, parameters, dedtypes, wm);
-
-    return m;
-}
-
-MATCH TypeClass::deduceTypeNoRecursion(Scope *sc, Type *tparam, TemplateParameters *parameters, Objects *dedtypes, unsigned *wm)
 {
     //printf("TypeClass::deduceType(this = %s)\n", toChars());
 

diff --git a/test/runnable/aliasthis.d b/test/runnable/aliasthis.d
@@ -407,30 +407,49 @@ void test7()
 /***************************************************/
 // 11875 - endless recursion in Type::deduceType
 
-struct T1(C)
+struct T11875x(C)
 {
     C c;
 }
-
-class D1 { D2 c; alias c this; }
-class D2 { D1 c; alias c this; }
-
-static assert(!is(D1 == D2));
-static if(is(T1!D1 == T1!D, D))
-    static assert(is(D == D1));
-static if(is(D1 == T1!D, D)) // this used to freeze dmd
-    static assert(false);
+class D11875a { D11875b c; alias c this; }
+class D11875b { D11875a c; alias c this; }
+static assert(!is(D11875a == D11875b));
+static assert( is(T11875x!D11875a == T11875x!D, D) && is(D == D11875a));
+static assert(!is(D11875a == T11875x!D, D));    // this used to freeze dmd
 
 // test that types in recursion are still detected
-class D3 { T2!D2 c; alias c this; }
-
-struct T2(C)
+struct T11875y(C)
 {
     C c;
     alias c this;
 }
-static assert(is(D3 : T2!D, D) && is(D == D2));
+class D11875c { T11875y!D11875b c; alias c this; }
+static assert(is(D11875c : T11875y!D, D) && is(D == D11875b));
+
+/***************************************************/
+// 11930
+
+class BarObj11930 {}
 
+struct Bar11930
+{
+    BarObj11930 _obj;
+    alias _obj this;
+}
+
+BarObj11930 getBarObj11930(T)(T t)
+{
+    static if (is(T unused : BarObj11930))
+        return t;
+    else
+        static assert(false, "Can not get BarObj from " ~ T.stringof);
+}
+
+void test11930()
+{
+    Bar11930 b;
+    getBarObj11930(b);
+}
 
 /***************************************************/
 // 2781