Fix parameter count bug in ambiguity checking for overloaded function matching…

Test/120.vert

@@ -72,6 +72,9 @@ vec3 overloadE(float[2]);
 vec3 overloadE(mat2 m);
 vec3 overloadE(vec2 v);
 
+vec3 overloadF(int);
+vec3 overloadF(float);
+
 void foo()
 {
     float f;
@@ -81,6 +84,7 @@ void foo()
     overloadB(f, 2);
     overloadB(1, i);
 
+    overloadC(1);    // ERROR
     overloadC(1, i);
     overloadC(vec2(1), vec2(2));
     overloadC(f, 3.0);           // ERROR, no way
@@ -109,4 +113,7 @@ void foo()
 
     float b[2];
     overloadE(b);
+    
+    overloadF(1, 1); // ERROR
+    overloadF(1);
 }

glslang/MachineIndependent/ParseHelper.cpp

@@ -2596,8 +2596,13 @@ const TFunction* TParseContext::findFunction120(TSourceLoc loc, const TFunction&
 
     int numPossibleMatches = 0;
     for (TVector<TFunction*>::const_iterator it = candidateList.begin(); it != candidateList.end(); ++it) {
-        bool possibleMatch = true;
         const TFunction& function = *(*it);
+
+        // to even be a potential match, number of arguments has to match
+        if (call.getParamCount() != function.getParamCount())
+            continue;
+
+        bool possibleMatch = true;
         for (int i = 0; i < function.getParamCount(); ++i) {
             // same types is easy
             if (*function[i].type == *call[i].type)