Error message: Finish addressing #2097, better texture error message.

Test/baseResults/vulkan.frag.out

@@ -7,14 +7,14 @@ ERROR: 0:8: 'binding' : sampler/texture/image requires layout(binding=X)
 ERROR: 0:9: 'binding' : sampler/texture/image requires layout(binding=X) 
 ERROR: 0:10: 'binding' : sampler/texture/image requires layout(binding=X) 
 ERROR: 0:14: 'sampler2D' : sampler-constructor requires two arguments 
-ERROR: 0:15: 'sampler2D' : sampler-constructor first argument must be a scalar textureXXX type 
-ERROR: 0:16: 'sampler2D' : sampler-constructor first argument must be a scalar textureXXX type 
-ERROR: 0:17: 'sampler2D' : sampler-constructor second argument must be a scalar type 'sampler' 
-ERROR: 0:18: 'sampler2D' : sampler-constructor second argument must be a scalar type 'sampler' 
-ERROR: 0:19: 'sampler2D' : sampler-constructor second argument must be a scalar type 'sampler' 
+ERROR: 0:15: 'sampler2D' : sampler-constructor first argument must be a scalar *texture* type 
+ERROR: 0:16: 'sampler2D' : sampler-constructor first argument must be a scalar *texture* type 
+ERROR: 0:17: 'sampler2D' : sampler-constructor second argument must be a scalar sampler or samplerShadow 
+ERROR: 0:18: 'sampler2D' : sampler-constructor second argument must be a scalar sampler or samplerShadow 
+ERROR: 0:19: 'sampler2D' : sampler-constructor second argument must be a scalar sampler or samplerShadow 
 ERROR: 0:21: 'sampler3D' : sampler-constructor cannot make an array of samplers 
-ERROR: 0:22: 'sampler2D' : sampler-constructor first argument must be a scalar textureXXX type 
-ERROR: 0:23: 'sampler2D' : sampler-constructor first argument must match type and dimensionality of constructor type 
+ERROR: 0:22: 'sampler2D' : sampler-constructor first argument must be a scalar *texture* type 
+ERROR: 0:23: 'sampler2D' : sampler-constructor first argument must be a *texture* type matching the dimensionality and sampled type of the constructor 
 ERROR: 0:28: 'sampler2D' : sampler/image types can only be used in uniform variables or function parameters: s2D
 ERROR: 0:29: 'sampler3D' : sampler-constructor cannot make an array of samplers 
 ERROR: 0:29: 'sampler3D' : sampler/image types can only be used in uniform variables or function parameters: s3d

glslang/MachineIndependent/ParseHelper.cpp

@@ -3152,7 +3152,7 @@ bool TParseContext::constructorTextureSamplerError(const TSourceLoc& loc, const
     if (function[0].type->getBasicType() != EbtSampler ||
         ! function[0].type->getSampler().isTexture() ||
         function[0].type->isArray()) {
-        error(loc, "sampler-constructor first argument must be a scalar textureXXX type", token, "");
+        error(loc, "sampler-constructor first argument must be a scalar *texture* type", token, "");
         return true;
     }
     // simulate the first argument's impact on the result type, so it can be compared with the encapsulated operator!=()
@@ -3160,7 +3160,8 @@ bool TParseContext::constructorTextureSamplerError(const TSourceLoc& loc, const
     texture.setCombined(false);
     texture.shadow = false;
     if (texture != function[0].type->getSampler()) {
-        error(loc, "sampler-constructor first argument must match type and dimensionality of constructor type", token, "");
+        error(loc, "sampler-constructor first argument must be a *texture* type"
+                   " matching the dimensionality and sampled type of the constructor", token, "");
         return true;
     }
 
@@ -3170,7 +3171,7 @@ bool TParseContext::constructorTextureSamplerError(const TSourceLoc& loc, const
     if (  function[1].type->getBasicType() != EbtSampler ||
         ! function[1].type->getSampler().isPureSampler() ||
           function[1].type->isArray()) {
-        error(loc, "sampler-constructor second argument must be a scalar type 'sampler'", token, "");
+        error(loc, "sampler-constructor second argument must be a scalar sampler or samplerShadow", token, "");
         return true;
     }