[Diag-Experimental-Formatting] Add a formatting test for Swift diags emitted in clang virtual files

Author: owenv

lib/Frontend/PrintingDiagnosticConsumer.cpp

@@ -697,7 +697,7 @@ namespace {
     void printLineEllipsis(raw_ostream &Out) {
       Out.changeColor(ColoredStream::Colors::CYAN, true);
       Out << llvm::formatv("{0}...\n",
-                           llvm::fmt_repeat(" ", getLineNumberIndent()));
+                           llvm::fmt_repeat(" ", getPreferredLineNumberIndent()));
       Out.resetColor();
     }
 

test/diagnostics/Inputs/RenamedObjc.h

@@ -0,0 +1,9 @@
+@import Foundation;
+
+#define SWIFT_NAME(X) __attribute__((swift_name(#X)))
+
+#pragma clang assume_nonnull begin
+@interface SwiftNameTest : NSObject
++ (instancetype)g:(id)x outParam:(int *)foo SWIFT_NAME(init(g:));
+@end
+#pragma clang assume_nonnull end

test/diagnostics/Inputs/module.map

@@ -0,0 +1,4 @@
+module RenamedObjc {
+  header "RenamedObjc.h"
+  export *
+}

test/diagnostics/pretty-printed-diags-in-clang-buffer.swift

@@ -0,0 +1,20 @@
+// RUN: %empty-directory(%t.mcp)
+// RUN: not %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-diagnostic-formatting -I %S/Inputs/ -typecheck %s -module-cache-path %t.mcp 2>&1 | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+import RenamedObjc
+
+let foo = SwiftNameTest(g: "")
+
+// CHECK: SOURCE_DIR{{[/\]+}}test{{[/\]+}}diagnostics{{[/\]+}}Inputs{{[/\]+}}RenamedObjc.h:7:1
+// CHECK: 7 | + (instancetype)g:(id)x outParam:(int *)foo SWIFT_NAME(init(g:));
+// CHECK:   | ^ warning: too few parameters in swift_name attribute (expected 2; got 1)
+// CHECK:   | ^ note: please report this issue to the owners of 'RenamedObjc'
+
+
+// CHECK: SOURCE_DIR{{[/\]+}}test{{[/\]+}}diagnostics{{[/\]+}}pretty-printed-diags-in-clang-buffer.swift:8:28
+// CHECK: 7 |
+// CHECK: 8 | let foo = SwiftNameTest(g: "")
+// CHECK:   |                            ~~
+// CHECK:   |                            ^ error: argument passed to call that takes no arguments