suppress redecl notes coming from interactive line includer

This follows the same behaviour as clang-repl, maybe this should be
fixed upstream.

Author: devajithvs

interpreter/cling/lib/Interpreter/IncrementalParser.cpp

@@ -183,6 +183,25 @@ namespace {
         }
       }
 
+      // FIXME:
+      // Suppress meaningless "note: '' included multiple times, additional
+      // include site here" from virtual Cling buffers.
+      // Also happens with clang-repl.
+      if (Info.getID() == diag::note_redefinition_include_same_file) {
+        if (!Info.hasSourceManager() || !Info.getLocation().isValid())
+          return;
+
+        const PresumedLoc PLoc =
+            Info.getSourceManager().getPresumedLoc(Info.getLocation());
+        if (!PLoc.isValid())
+          return;
+
+        StringRef Filename = PLoc.getFilename();
+        if (Filename.empty() ||
+            Filename.contains("cling interactive line includer"))
+          return;
+      }
+
       // In principle, for simplicity, we preserve the old behavior of
       // delivering diagnostics to just one consumer (that is why we don't emit
       // to both), but we allow the "sink" to be changed.
@@ -888,7 +907,7 @@ namespace cling {
 
     // Create SourceLocation, which will allow clang to order the overload
     // candidates for example
-    SourceLocation NewLoc = getNextAvailableUniqueSourceLoc();
+    SourceLocation NewLoc = SM.getLocForStartOfFile(SM.getMainFileID());
 
     // Create FileID for the current buffer.
     FileID FID = SM.createFileID(std::move(MB), SrcMgr::C_User, /*LoadedID=*/0,

interpreter/cling/test/ErrorRecovery/MacroExpansion.C

@@ -13,7 +13,7 @@
 
 .rawInput 1
 
-BEGIN_NAMESPACE int j; END_NAMESPACE // expected-note {{previous definition is here}}
+BEGIN_NAMESPACE int j; END_NAMESPACE
 
 .storeState "testMacroExpansion"
 BEGIN_NAMESPACE int j; END_NAMESPACE // expected-error {{redefinition of 'j'}}

interpreter/cling/test/ErrorRecovery/SubsequentDecls.C

@@ -46,7 +46,7 @@ TemplatedF((double)3.14)
 
 // ROOT-7295
 #include <vector>
-std::vector<float> a; // expected-note {{previous definition is here}}
+std::vector<float> a;
 std::vector<float> a; // expected-error {{redefinition of 'a'}}
 
 .q

interpreter/cling/test/Prompt/Redeclarations.C

@@ -13,7 +13,7 @@ struct MyClass{} // expected-error {{redefinition of 'MyClass'}}
 MyClass * s; // expected-note {{previous definition is here}}
 MyClass s; // expected-error {{redefinition of 's'}}
 
-const char* a = "test"; // expected-note {{previous definition is here}}
+const char* a = "test";
 const char* a = ""; // expected-error {{redefinition of 'a'}}
 
 .q