Add #warning and #error macro declarations to the standard library

Author: DougGregor

stdlib/public/core/CMakeLists.txt

@@ -290,6 +290,7 @@ endif()
 list(APPEND swift_stdlib_compile_flags "-Xfrontend" "-enable-experimental-concise-pound-file")
 
 list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "Macros")
+list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "FreestandingMacros")
 
 if(SWIFT_CHECK_ESSENTIAL_STDLIB)
   add_swift_target_library(swift_stdlib_essential ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB IS_STDLIB_CORE

stdlib/public/core/Macros.swift

@@ -93,4 +93,12 @@ public macro dsohandle() -> UnsafeRawPointer = Builtin.DSOHandleMacro
 public macro OptionSet<RawType>() =
   #externalMacro(module: "SwiftMacros", type: "OptionSetMacro")
 
+/// Produce the given warning message during compilation.
+@freestanding(declaration)
+public macro warning(_ message: String) = Builtin.WarningMacro
+
+/// Produce the given error message during compilation.
+@freestanding(declaration)
+public macro error(_ message: String) = Builtin.ErrorMacro
+
 #endif

test/IDE/complete_pound_expr.swift

@@ -15,8 +15,10 @@ func test1() {
   let _ = useSelector(##^POUND_EXPR_3^#)
 }
 
-// POUND_EXPR_INTCONTEXT: Begin completions, 8 items
+// POUND_EXPR_INTCONTEXT: Begin completions, 10 items
 // POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: function[#ExpressibleByStringLiteral#]; name=function
+// POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: warning({#(message): String#})[#Void#]; name=warning(:)
+// POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: error({#(message): String#})[#Void#]; name=error(:)
 // POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: fileID[#ExpressibleByStringLiteral#]; name=fileID
 // POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: file[#ExpressibleByStringLiteral#]; name=file
 // POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: dsohandle[#UnsafeRawPointer#]; name=dsohandle
@@ -26,8 +28,10 @@ func test1() {
 // POUND_EXPR_INTCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: filePath[#ExpressibleByStringLiteral#]; name=filePath
 // POUND_EXPR_INTCONTEXT: End completions
 
-// POUND_EXPR_STRINGCONTEXT: Begin completions, 9 items
+// POUND_EXPR_STRINGCONTEXT: Begin completions, 11 items
 // POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: function[#ExpressibleByStringLiteral#]; name=function
+// POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: warning({#(message): String#})[#Void#]; name=warning(:)
+// POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: error({#(message): String#})[#Void#]; name=error(:)
 // POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: fileID[#ExpressibleByStringLiteral#]; name=fileID
 // POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: file[#ExpressibleByStringLiteral#]; name=file
 // POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: dsohandle[#UnsafeRawPointer#]; name=dsohandle
@@ -38,8 +42,10 @@ func test1() {
 // POUND_EXPR_STRINGCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: externalMacro({#module: String#}, {#type: String#})[#T#]; name=externalMacro(module:type:)
 // POUND_EXPR_STRINGCONTEXT: End completions
 
-// POUND_EXPR_SELECTORCONTEXT: Begin completions, 9 items
+// POUND_EXPR_SELECTORCONTEXT: Begin completions, 11 items
 // POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: function[#ExpressibleByStringLiteral#]; name=function
+// POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: warning({#(message): String#})[#Void#]; name=warning(:)
+// POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: error({#(message): String#})[#Void#]; name=error(:)
 // POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: fileID[#ExpressibleByStringLiteral#]; name=fileID
 // POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: file[#ExpressibleByStringLiteral#]; name=file
 // POUND_EXPR_SELECTORCONTEXT-DAG: Decl[Macro]/OtherModule[Swift]/IsSystem: dsohandle[#UnsafeRawPointer#]; name=dsohandle