fix Issue 14907 - DMD crash when using template name as a default val…

…ue of template's typed argument
dlang · Jan 18, 2018 · a498667 · a498667
1 parent 42546a3
commit a498667
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Showing 3 changed files with 53 additions and 4 deletions.
diff --git a/src/dmd/dtemplate.d b/src/dmd/dtemplate.d
@@ -518,6 +518,7 @@ extern (C++) final class TemplateDeclaration : ScopeDsymbol
     bool ismixin;           // template declaration is only to be used as a mixin
     bool isstatic;          // this is static template declaration
     Prot protection;
+    int inuse;              /// for recursive expansion detection
 
     // threaded list of previous instantiation attempts on stack
     TemplatePrevious* previous;
@@ -855,7 +856,9 @@ extern (C++) final class TemplateDeclaration : ScopeDsymbol
                     printf("\tparameter[%d] is %s : %s\n", i, tp.ident.toChars(), ttp.specType ? ttp.specType.toChars() : "");
             }
 
+            inuse++;
             m2 = tp.matchArg(ti.loc, paramscope, ti.tiargs, i, parameters, dedtypes, &sparam);
+            inuse--;
             //printf("\tm2 = %d\n", m2);
             if (m2 == MATCH.nomatch)
             {
@@ -1513,7 +1516,9 @@ extern (C++) final class TemplateDeclaration : ScopeDsymbol
                                 }
                                 else
                                 {
+                                    inuse++;
                                     oded = tparam.defaultArg(instLoc, paramscope);
+                                    inuse--;
                                     if (oded)
                                         (*dedargs)[i] = declareParameter(paramscope, tparam, oded);
                                 }
@@ -1884,7 +1889,9 @@ extern (C++) final class TemplateDeclaration : ScopeDsymbol
                 }
                 else
                 {
+                    inuse++;
                     oded = tparam.defaultArg(instLoc, paramscope);
+                    inuse--;
                     if (!oded)
                     {
                         // if tuple parameter and
@@ -2497,8 +2504,12 @@ void functionResolve(Match* m, Dsymbol dstart, Loc loc, Scope* sc, Objects* tiar
     int applyTemplate(TemplateDeclaration td)
     {
         //printf("applyTemplate()\n");
-        // skip duplicates
-        if (td == td_best)
+        if (td.inuse)
+        {
+            td.error(loc, "recursive template expansion");
+            return 1;
+        }
+        if (td == td_best)   // skip duplicates
             return 0;
 
         if (!sc)
@@ -5352,12 +5363,15 @@ extern (C++) final class TemplateValueParameter : TemplateParameter
         if (e)
         {
             e = e.syntaxCopy();
+            uint olderrs = global.errors;
             if ((e = e.expressionSemantic(sc)) is null)
                 return null;
             if ((e = resolveProperties(sc, e)) is null)
                 return null;
             e = e.resolveLoc(instLoc, sc); // use the instantiated loc
             e = e.optimize(WANTvalue);
+            if (global.errors != olderrs)
+                e = new ErrorExp();
         }
         return e;
     }
@@ -6882,8 +6896,15 @@ extern (C++) class TemplateInstance : ScopeDsymbol
             Dsymbol dstart = tovers ? tovers.a[oi] : tempdecl;
             overloadApply(dstart, (Dsymbol s)
             {
-                auto  td = s.isTemplateDeclaration();
-                if (!td || td == td_best)   // skip duplicates
+                auto td = s.isTemplateDeclaration();
+                if (!td)
+                    return 0;
+                if (td.inuse)
+                {
+                    td.error(loc, "recursive template expansion");
+                    return 1;
+                }
+                if (td == td_best)   // skip duplicates
                     return 0;
 
                 //printf("td = %s\n", td.toPrettyChars());
@@ -7051,6 +7072,11 @@ extern (C++) class TemplateInstance : ScopeDsymbol
                 auto td = s.isTemplateDeclaration();
                 if (!td)
                     return 0;
+                if (td.inuse)
+                {
+                    td.error(loc, "recursive template expansion");
+                    return 1;
+                }
 
                 /* If any of the overloaded template declarations need inference,
                  * then return true

diff --git a/src/dmd/template.h b/src/dmd/template.h
@@ -79,6 +79,7 @@ class TemplateDeclaration : public ScopeDsymbol
     bool ismixin;               // template declaration is only to be used as a mixin
     bool isstatic;              // this is static template declaration
     Prot protection;
+    int inuse;                  // for recursive expansion detection
 
     TemplatePrevious *previous;         // threaded list of previous instantiation attempts on stack
 

diff --git a/test/fail_compilation/ice14907.d b/test/fail_compilation/ice14907.d
@@ -0,0 +1,22 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/ice14907.d(14): Error: struct ice14907.S(int v = S) recursive template expansion
+fail_compilation/ice14907.d(19):        while looking for match for `S!()`
+fail_compilation/ice14907.d(15): Error: template ice14907.f(int v = f)() recursive template expansion
+fail_compilation/ice14907.d(20):        while looking for match for `f!()`
+fail_compilation/ice14907.d(15): Error: template ice14907.f(int v = f)() recursive template expansion
+fail_compilation/ice14907.d(21): Error: template `ice14907.f` cannot deduce function from argument types `!()()`, candidates are:
+fail_compilation/ice14907.d(15):        `ice14907.f(int v = f)()`
+---
+*/
+
+struct S(int v = S) {}
+void f(int v = f)() {}
+
+void main()
+{
+    S!() s;     // OK <- ICE
+    f!()();     // OK <- ICE
+    f();        // OK <- ICE
+}