[tint] Move potential type creation out of ValidateReturn.

This CL moves the possible call to create the return type out of the
ValidateReturn and into the call. The type is then passed into the
ValidateReturn method.

Bug: tint:1313
Change-Id: I5d2e78b945fc47a14072f503d0478a7da051137d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/87146
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>

src/tint/resolver/resolver.cc

@@ -2507,7 +2507,9 @@ sem::Statement* Resolver::ReturnStatement(const ast::ReturnStatement* stmt) {
 
     // Validate after processing the return value expression so that its type
     // is available for validation.
-    return ValidateReturn(stmt, current_function_->ReturnType());
+    auto* ret_type = stmt->value ? TypeOf(stmt->value)->UnwrapRef()
+                                 : builder_->create<sem::Void>();
+    return ValidateReturn(stmt, current_function_->ReturnType(), ret_type);
   });
 }
 

src/tint/resolver/resolver.h

@@ -281,7 +281,8 @@ class Resolver {
                                  const sem::Variable* var);
   bool ValidateParameter(const ast::Function* func, const sem::Variable* var);
   bool ValidateReturn(const ast::ReturnStatement* ret,
-                      const sem::Type* func_type);
+                      const sem::Type* func_type,
+                      const sem::Type* ret_type);
   bool ValidateStatements(const ast::StatementList& stmts);
   bool ValidateStorageTexture(const ast::StorageTexture* t);
   bool ValidateStructure(const sem::Struct* str, ast::PipelineStage stage);

src/tint/resolver/resolver_validation.cc

@@ -2182,10 +2182,8 @@ bool Resolver::ValidateLocationAttribute(
 }
 
 bool Resolver::ValidateReturn(const ast::ReturnStatement* ret,
-                              const sem::Type* func_type) {
-  auto* ret_type = ret->value ? TypeOf(ret->value)->UnwrapRef()
-                              : builder_->create<sem::Void>();
-
+                              const sem::Type* func_type,
+                              const sem::Type* ret_type) {
   if (func_type->UnwrapRef() != ret_type) {
     AddError(
         "return statement type must match its function "