Parser: report error on missing first item in tuple expressions (#15999)

Author: auduchinok

src/Compiler/pars.fsy

@@ -5173,6 +5173,7 @@ parenExpr:
       { let mComma = rhs parseState 2
         let mLparen = rhs parseState 1
         let mRparen = rhs parseState 3
+        reportParseErrorAt mComma (FSComp.SR.parsExpectingExpression ())
         let errorExpr = arbExpr ("tupleExpr3", mComma.EndRange)
         let mTuple = unionRanges mComma $3.Range
         let tupleExpr =

tests/service/data/SyntaxTree/Expression/Tuple - Missing item 02.fs.bsl

@@ -15,3 +15,5 @@ ImplFile
           (1,0--3,4), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
       { ConditionalDirectives = []
         CodeComments = [] }, set []))
+
+(3,1)-(3,2) parse error Expecting expression

tests/service/data/SyntaxTree/Expression/Tuple - Missing item 03.fs.bsl

@@ -15,3 +15,5 @@ ImplFile
           (1,0--3,6), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
       { ConditionalDirectives = []
         CodeComments = [] }, set []))
+
+(3,1)-(3,2) parse error Expecting expression