Don't test directly against Scanner::kNoSourcePos instead use >= 0.

runtime/vm/flow_graph_compiler_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 1402 matching lines @@
     __ sw(reg, Address(SP, 1 * kWordSize));
     __ LoadObject(TMP, obj);
     __ sw(TMP, Address(SP, 0 * kWordSize));
     if (is_optimizing()) {
       __ BranchLinkPatchable(
           *StubCode::OptimizedIdenticalWithNumberCheck_entry());
     } else {
       __ BranchLinkPatchable(
           *StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);
     }
     __ Comment("EqualityRegConstCompare return");
     // Stub returns result in CMPRES1 (if it is 0, then reg and obj are equal).
     __ lw(reg, Address(SP, 1 * kWordSize));  // Restore 'reg'.
     __ addiu(SP, SP, Immediate(2 * kWordSize));  // Discard constant.
     return Condition(CMPRES1, ZR, EQ);
   } else {
@@ skipping 13 matching lines @@
     __ addiu(SP, SP, Immediate(-2 * kWordSize));
     __ sw(left, Address(SP, 1 * kWordSize));
     __ sw(right, Address(SP, 0 * kWordSize));
     if (is_optimizing()) {
       __ BranchLinkPatchable(
           *StubCode::OptimizedIdenticalWithNumberCheck_entry());
     } else {
       __ BranchLinkPatchable(
           *StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);
     }
     __ Comment("EqualityRegRegCompare return");
     // Stub returns result in CMPRES1 (if it is 0, then left and right are
     // equal).
     __ lw(right, Address(SP, 0 * kWordSize));
     __ lw(left, Address(SP, 1 * kWordSize));
     __ addiu(SP, SP, Immediate(2 * kWordSize));
@@ skipping 429 matching lines @@
   __ AddImmediate(SP, kDoubleSize);
 }
 
 
 #undef __
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS