Add static optimizations for string, char, and bool

For culture-independent types (string, char, bool), bypass the
`string` operator and call the appropriate TextWriter.Write/WriteLine
overload directly.

Numeric types (int, float, etc.) must still go through `string` to
ensure InvariantCulture formatting, since TextWriter.Write(int/float)
uses the writer's FormatProvider which is CurrentCulture for Console.Out.

Add IL tests verifying char and bool use their direct overloads.

Author: bbatsov

.fantomasignore

@@ -75,6 +75,7 @@ src/Compiler/SyntaxTree/LexFilter.fs
 
 src/FSharp.Core/array2.fs
 src/FSharp.Core/array3.fs
+src/FSharp.Core/fslib-extra-pervasives.fs
 src/FSharp.Core/Linq.fs
 src/FSharp.Core/local.fs
 src/FSharp.Core/nativeptr.fs

src/FSharp.Core/fslib-extra-pervasives.fs

@@ -280,10 +280,19 @@ module ExtraTopLevelOperators =
     [<CompiledName("PrintValue")>]
     let inline print (value: 'T) =
         Console.Out.Write(string value)
+        // Culture-independent types can bypass 'string' and use TextWriter overloads directly.
+        // Numeric types must go through 'string' to ensure InvariantCulture formatting,
+        // since TextWriter.Write(int/float/...) uses the writer's FormatProvider (CurrentCulture).
+        when 'T : string = Console.Out.Write((# "" value : string #))
+        when 'T : char   = Console.Out.Write((# "" value : char #))
+        when 'T : bool   = Console.Out.Write((# "" value : bool #))
 
     [<CompiledName("PrintValueLine")>]
     let inline printn (value: 'T) =
         Console.Out.WriteLine(string value)
+        when 'T : string = Console.Out.WriteLine((# "" value : string #))
+        when 'T : char   = Console.Out.WriteLine((# "" value : char #))
+        when 'T : bool   = Console.Out.WriteLine((# "" value : bool #))
 
     [<CompiledName("DefaultAsyncBuilder")>]
     let async = AsyncBuilder()

tests/FSharp.Compiler.ComponentTests/EmittedIL/PrintFunction.fs

@@ -40,7 +40,7 @@ let printnInt () = printn 42
              """callvirt   instance void [netstandard]System.IO.TextWriter::WriteLine(string)"""]
 
     [<Fact>]
-    let ``print with string writes to Console Out``() =
+    let ``print with string calls Write directly``() =
         FSharp """
 module PrintString
 
@@ -53,6 +53,34 @@ let printStr () = print "hello"
              """call       class [netstandard]System.IO.TextWriter [netstandard]System.Console::get_Out()"""
              """callvirt   instance void [netstandard]System.IO.TextWriter::Write(string)"""]
 
+    [<Fact>]
+    let ``print with char calls Write char overload``() =
+        FSharp """
+module PrintChar
+
+let printChar () = print 'A'
+         """
+         |> withOptimize
+         |> compile
+         |> shouldSucceed
+         |> verifyIL [
+             """call       class [netstandard]System.IO.TextWriter [netstandard]System.Console::get_Out()"""
+             """callvirt   instance void [netstandard]System.IO.TextWriter::Write(char)"""]
+
+    [<Fact>]
+    let ``print with bool calls Write bool overload``() =
+        FSharp """
+module PrintBool
+
+let printBool () = print true
+         """
+         |> withOptimize
+         |> compile
+         |> shouldSucceed
+         |> verifyIL [
+             """call       class [netstandard]System.IO.TextWriter [netstandard]System.Console::get_Out()"""
+             """callvirt   instance void [netstandard]System.IO.TextWriter::Write(bool)"""]
+
     [<Fact>]
     let ``printn with float specializes to Double ToString with InvariantCulture``() =
         FSharp """