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Author: OwnageIsMagic

src/Compiler/Checking/NameResolution.fs

@@ -3245,7 +3245,7 @@ let rec ResolvePatternLongIdentPrim sink (ncenv: NameResolver) fullyQualified wa
                     not newDef
                     && warnOnUpper = WarnOnUpperCase
                     && id.idText.Length >= 3
-                    && System.Char.IsUpper id.idText[0]
+                    && System.Char.ToLowerInvariant id.idText[0] <> id.idText[0]
                 then
                     warning(UpperCaseIdentifierInPattern m)
 

src/Compiler/Utilities/illib.fs

@@ -80,7 +80,8 @@ module internal PervasiveAutoOpens =
         member inline x.EndsWithOrdinalIgnoreCase value =
             x.EndsWith(value, StringComparison.OrdinalIgnoreCase)
 
-    let inline isDigit (c: char) = (uint) (c - '0') <= (uint) ('9' - '0')
+    // Backport of Char.IsAsciiDigit. Do not use Char.IsDigit
+    let inline isDigit (c: char) = uint (c - '0') <= uint ('9' - '0')
 
     /// Get an initialization hole
     let getHole (r: _ ref) =

src/FSharp.Core/printf.fs

@@ -84,7 +84,8 @@ module internal PrintfImpl =
     let inline isPlusForPositives flags = hasFlag flags FormatFlags.PlusForPositives
     let inline isSpaceForPositives flags = hasFlag flags FormatFlags.SpaceForPositives
 
-    let inline isDigit (c: char) = (uint)(c - '0') <= (uint)('9' - '0');
+    // Backport of Char.IsAsciiDigit. Do not use Char.IsDigit
+    let inline isDigit (c: char) = uint (c - '0') <= uint ('9' - '0')
 
     /// Used for width and precision to denote that user has specified '*' flag
     [<Literal>]