[Diagnostics] Add tests to check diagnostic locations across modules

test/diagnostics/loc-directive-diagnostics.swift

@@ -0,0 +1,7 @@
+// RUN: not %target-swift-frontend -typecheck %s 2>&1 | %FileCheck %s
+
+#sourceLocation(file: "anything.swift", line: 1)
+func 1() {}
+#sourceLocation()
+
+// CHECK: anything.swift:1:6: error: function name

test/diagnostics/multi-module-diagnostics.swift

@@ -0,0 +1,78 @@
+#if MODA_NORMAL
+open class ParentClass {
+  open func overridableMethod(param: Int) {}
+}
+#endif
+
+#if MODA_LOC
+open class ParentClass {
+#sourceLocation(file: "REPLACEDWITHSED", line: 10)
+  open func overridableMethod(param: Int) {}
+#sourceLocation()
+}
+#endif
+
+#if MODB
+import moda
+
+open class SubClass: ParentClass {
+  open override func overridableMethod(param: String) {}
+}
+#endif
+
+// This test depends on line numbers, hence RUN lines being underneath the
+// code.
+
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/mods)
+// RUN: sed -e 's|REPLACEDWITHSED|%/t/alternative.swift|g' %s > %t/moda.swift
+
+// RUN: %target-swift-frontend -emit-module -emit-module-source-info -o %t/mods/moda.swiftmodule -D MODA_NORMAL %t/moda.swift
+
+// The diagnostic should have the real location from .swiftsourceinfo
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-EXISTS %s
+// CHECK-EXISTS: moda.swift:3:13: note
+
+// Removed the underlying file, so should use the generated source instead
+// RUN: mv %t/moda.swift %t/moda.swift-moved
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-GENERATED %s
+// CHECK-GENERATED: moda.ParentClass:{{.*}}: note:
+
+// Underlying file has changed, so the locations in .swiftsourceinfo may not
+// make sense any more. Ignored for now (ie. it is used regardless)
+// RUN: echo "// file was modified" > %t/moda.swift
+// RUN: cat %t/moda.swift-moved >> %t/moda.swift
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-EXISTS %s
+
+
+// The file and line from a location directive should be used whether or not it
+// exists - the actual source still comes from the original file, so that's what
+// matters in terms of whether generated code is used or not
+
+// RUN: %empty-directory(%t/mods)
+// RUN: mv %t/moda.swift-moved %t/moda.swift
+// RUN: %target-swift-frontend -emit-module -emit-module-source-info -o %t/mods/moda.swiftmodule -D MODA_LOC %t/moda.swift
+
+// Line directive file exists
+// RUN: cp %t/moda.swift %t/alternative.swift
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-DIRECTIVE %s
+
+// File missing
+// RUN: mv %t/alternative.swift %t/alternative.swift-moved
+// FIXME: Because the presumed location is output and then read back in, the
+//        location is invalid and it falls back to the generated. This should be
+//        CHECK-DIRECTIVE
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-GENERATED %s
+// CHECK-DIRECTIVE: alternative.swift:10:13: note
+
+// File exists but location does not
+// RUN: echo "" > %t/alternative.swift
+// FIXME: As above, this should be CHECK-DIRECTIVE
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-GENERATED %s
+
+// Removed the underlying file, so should use the generated source instead
+// RUN: mv %t/alternative.swift-moved %t/alternative.swift
+// RUN: mv %t/moda.swift %t/moda.swift-moved
+// FIXME: Should be CHECK-GENERATED but works as, again, it's the presumed
+//        location that's output
+// RUN: not %target-swift-frontend -typecheck -I %t/mods -D MODB %s 2>&1 | %FileCheck -check-prefix=CHECK-DIRECTIVE %s