warn about inconsistent spacing around binary operators; fixes #7582

changelog.md

@@ -17,6 +17,9 @@
 - The ``not nil`` type annotation now has to be enabled explicitly
   via ``{.experimental: "notnil"}`` as we are still not pleased with how this
   feature works with Nim's containers.
+- The parser now warns about inconsistent spacing around binary operators as
+  these can easily be confused with unary operators. This warning will likely
+  become an error in the future.
 
 
 #### Breaking changes in the standard library
@@ -89,7 +92,7 @@
 - Accessing the binary zero terminator in Nim's native strings
   is now invalid. Internally a Nim string still has the trailing zero for
   zero-copy interoperability with ``cstring``. Compile your code with the
-  next switch ``--laxStrings:on`` if you need a transition period.
+  new switch ``--laxStrings:on`` if you need a transition period.
 
 
 ### Tool changes

compiler/msgs.nim

@@ -131,7 +131,7 @@ type
     warnEachIdentIsTuple, warnShadowIdent,
     warnProveInit, warnProveField, warnProveIndex, warnGcUnsafe, warnGcUnsafe2,
     warnUninit, warnGcMem, warnDestructor, warnLockLevel, warnResultShadowed,
-    warnUser,
+    warnInconsistentSpacing, warnUser,
     hintSuccess, hintSuccessX,
     hintLineTooLong, hintXDeclaredButNotUsed, hintConvToBaseNotNeeded,
     hintConvFromXtoItselfNotNeeded, hintExprAlwaysX, hintQuitCalled,
@@ -416,6 +416,7 @@ const
     warnDestructor: "usage of a type with a destructor in a non destructible context. This will become a compile time error in the future.",
     warnLockLevel: "$1",
     warnResultShadowed: "Special variable 'result' is shadowed.",
+    warnInconsistentSpacing: "Number of spaces around '$#' is not consistent",
     warnUser: "$1",
     hintSuccess: "operation successful",
     hintSuccessX: "operation successful ($# lines compiled; $# sec total; $#; $#)",
@@ -454,7 +455,8 @@ const
     "TypelessParam", "UseBase", "WriteToForeignHeap",
     "UnsafeCode", "EachIdentIsTuple", "ShadowIdent",
     "ProveInit", "ProveField", "ProveIndex", "GcUnsafe", "GcUnsafe2", "Uninit",
-    "GcMem", "Destructor", "LockLevel", "ResultShadowed", "User"]
+    "GcMem", "Destructor", "LockLevel", "ResultShadowed",
+    "Spacing", "User"]
 
   HintsToStr* = ["Success", "SuccessX", "LineTooLong",
     "XDeclaredButNotUsed", "ConvToBaseNotNeeded", "ConvFromXtoItselfNotNeeded",

compiler/parser.nim

@@ -268,13 +268,9 @@ proc isUnary(p: TParser): bool =
 proc checkBinary(p: TParser) {.inline.} =
   ## Check if the current parser token is a binary operator.
   # we don't check '..' here as that's too annoying
-  if p.strongSpaces and p.tok.tokType == tkOpr:
+  if p.tok.tokType == tkOpr:
     if p.tok.strongSpaceB > 0 and p.tok.strongSpaceA != p.tok.strongSpaceB:
-      parMessage(p, errGenerated,
-                 "Number of spaces around '$#' not consistent" %
-                 prettyTok(p.tok))
-    elif p.tok.strongSpaceA notin {0,1,2,4,8}:
-      parMessage(p, errGenerated, "Number of spaces must be 0,1,2,4 or 8")
+      parMessage(p, warnInconsistentSpacing, prettyTok(p.tok))
 
 #| module = stmt ^* (';' / IND{=})
 #|