Error message: Improve error message (will help another party id a bug).

Test/baseResults/120.frag.out

@@ -19,7 +19,7 @@ ERROR: 0:82: 'xr' : vector swizzle selectors not from the same set
 ERROR: 0:83: 'xyxyx' : vector swizzle too long 
 ERROR: 0:84: 'z' : vector swizzle selection out of range 
 ERROR: 0:85: 'assign' :  l-value required 
-ERROR: 0:91: 'int' : overloaded functions must have the same return type 
+ERROR: 0:91: 'main' : overloaded functions must have the same return type 
 ERROR: 0:91: 'main' : function already has a body 
 ERROR: 0:91: 'int' :  entry point cannot return a value
 ERROR: 0:92: 'main' : function cannot take any parameter(s) 

Test/baseResults/120.vert.out

@@ -34,7 +34,7 @@ ERROR: 0:51: 'arrays of arrays' : not supported with this profile: none
 ERROR: 0:52: 'arrays of arrays' : not supported with this profile: none
 ERROR: 0:53: 'arrays of arrays' : not supported with this profile: none
 ERROR: 0:56: 'out' : overloaded functions must have the same parameter storage qualifiers for argument 1
-ERROR: 0:57: 'float' : overloaded functions must have the same return type 
+ERROR: 0:57: 'overloadA' : overloaded functions must have the same return type 
 ERROR: 0:87: 'overloadC' : no matching overloaded function found 
 ERROR: 0:90: 'overloadC' : no matching overloaded function found 
 ERROR: 0:95: 'overloadD' : ambiguous function signature match: multiple signatures match under implicit type conversion 

glslang/MachineIndependent/ParseHelper.cpp

@@ -776,7 +776,7 @@ TFunction* TParseContext::handleFunctionDeclarator(const TSourceLoc& loc, TFunct
         if (prevDec->isPrototyped() && prototype)
             profileRequires(loc, EEsProfile, 300, nullptr, "multiple prototypes for same function");
         if (prevDec->getType() != function.getType())
-            error(loc, "overloaded functions must have the same return type", function.getType().getBasicTypeString().c_str(), "");
+            error(loc, "overloaded functions must have the same return type", function.getName().c_str(), "");
         for (int i = 0; i < prevDec->getParamCount(); ++i) {
             if ((*prevDec)[i].type->getQualifier().storage != function[i].type->getQualifier().storage)
                 error(loc, "overloaded functions must have the same parameter storage qualifiers for argument", function[i].type->getStorageQualifierString(), "%d", i+1);