Type checker: don't suppress errors while checking expressions

docs/release-notes/.FSharp.Compiler.Service/9.0.300.md

@@ -17,6 +17,7 @@
 * Add support for C# `Experimental` attribute. ([PR #18253](https://github.com/dotnet/fsharp/pull/18253))
 * Nullness warnings are issued for signature<>implementation conformance ([PR #18186](https://github.com/dotnet/fsharp/pull/18186))
 * Symbols: Add FSharpAssembly.IsFSharp ([PR #18290](https://github.com/dotnet/fsharp/pull/18290))
+* Type checker: don't suppress errors while checking expressions ([PR #18311](https://github.com/dotnet/fsharp/pull/18311))
 
 ### Changed
 

src/Compiler/Checking/Expressions/CheckExpressions.fs

@@ -5958,7 +5958,7 @@ and TcExprUndelayed (cenv: cenv) (overallTy: OverallTy) env tpenv (synExpr: SynE
 
     | SynExpr.FromParseError (expr1, m) ->
         //SolveTypeAsError cenv env.DisplayEnv m overallTy
-        let _, tpenv = suppressErrorReporting (fun () -> TcExpr cenv overallTy env tpenv expr1)
+        let _, tpenv = TcExpr cenv overallTy env tpenv expr1
         mkDefault(m, overallTy.Commit), tpenv
 
     | SynExpr.Sequential (sp, dir, synExpr1, synExpr2, m, _) ->
@@ -6487,9 +6487,7 @@ and TcIteratedLambdas (cenv: cenv) isFirst (env: TcEnv) overallTy takenNames tpe
 
     | e ->
         let env = { env with eIsControlFlow = true }
-        // Dive into the expression to check for syntax errors and suppress them if they show.
-        conditionallySuppressErrorReporting (not isFirst && synExprContainsError e) (fun () ->
-            TcExpr cenv overallTy env tpenv e)
+        TcExpr cenv overallTy env tpenv e
 
 and TcTyparExprThen (cenv: cenv) overallTy env tpenv synTypar m delayed =
     match delayed with
@@ -11093,39 +11091,33 @@ and TcNormalizedBinding declKind (cenv: cenv) env tpenv overallTy safeThisValOpt
         // At each module binding, dive into the expression to check for syntax errors and suppress them if they show.
         // Don't do this for lambdas, because we always check for suppression for all lambda bodies in TcIteratedLambdas
         let rhsExprChecked, tpenv =
-            let atTopNonLambdaDefn =
-                declKind.IsModuleOrMemberOrExtensionBinding &&
-                (match rhsExpr with SynExpr.Lambda _ -> false | _ -> true) &&
-                synExprContainsError rhsExpr
-
-            conditionallySuppressErrorReporting atTopNonLambdaDefn (fun () ->
-
-                // Save the arginfos away to match them up in the lambda
-                let (PrelimValReprInfo(argInfos, _)) = prelimValReprInfo
-
-                // The right-hand-side is control flow (has an implicit debug point) in any situation where we
-                // haven't extended the debug point to include the 'let', that is, there is a debug point noted
-                // at the binding.
-                //
-                // This includes
-                //    let _ = expr
-                //    let () = expr
-                // which are transformed to sequential expressions in TcLetBinding
-                //
-                let rhsIsControlFlow =
-                    match pat with
-                    | SynPat.Wild _
-                    | SynPat.Const (SynConst.Unit, _)
-                    | SynPat.Paren (SynPat.Const (SynConst.Unit, _), _) -> true
-                    | _ ->
-                    match debugPoint with
-                    | DebugPointAtBinding.Yes _ -> false
-                    | _ -> true
+            // Save the arginfos away to match them up in the lambda
+            let (PrelimValReprInfo(argInfos, _)) = prelimValReprInfo
+
+            // The right-hand-side is control flow (has an implicit debug point) in any situation where we
+            // haven't extended the debug point to include the 'let', that is, there is a debug point noted
+            // at the binding.
+            //
+            // This includes
+            //    let _ = expr
+            //    let () = expr
+            // which are transformed to sequential expressions in TcLetBinding
+            //
+            let rhsIsControlFlow =
+                match pat with
+                | SynPat.Wild _
+                | SynPat.Const (SynConst.Unit, _)
+                | SynPat.Paren (SynPat.Const (SynConst.Unit, _), _) -> true
+                | _ ->
+
+                match debugPoint with
+                | DebugPointAtBinding.Yes _ -> false
+                | _ -> true
 
-                let envinner = { envinner with eLambdaArgInfos = argInfos; eIsControlFlow = rhsIsControlFlow }
+            let envinner = { envinner with eLambdaArgInfos = argInfos; eIsControlFlow = rhsIsControlFlow }
 
-                if isCtor then TcExprThatIsCtorBody (safeThisValOpt, safeInitInfo) cenv (MustEqual overallExprTy) envinner tpenv rhsExpr
-                else TcExprThatCantBeCtorBody cenv (MustConvertTo (false, overallExprTy)) envinner tpenv rhsExpr)
+            if isCtor then TcExprThatIsCtorBody (safeThisValOpt, safeInitInfo) cenv (MustEqual overallExprTy) envinner tpenv rhsExpr
+            else TcExprThatCantBeCtorBody cenv (MustConvertTo (false, overallExprTy)) envinner tpenv rhsExpr
 
         if kind = SynBindingKind.StandaloneExpression && not cenv.isScript then
             UnifyUnitType cenv env mBinding overallPatTy rhsExprChecked |> ignore<bool>

tests/fsharp/typecheck/sigs/neg104.vsbsl

@@ -23,6 +23,8 @@ neg104.fs(8,9,8,15): typecheck error FS0750: This construct may only be used wit
 
 neg104.fs(10,9,10,15): typecheck error FS0750: This construct may only be used within computation expressions
 
+neg104.fs(13,21,13,26): typecheck error FS0003: This value is not a function and cannot be applied.
+
 neg104.fs(20,9,20,15): typecheck error FS0025: Incomplete pattern matches on this expression.
 
 neg104.fs(23,9,23,15): typecheck error FS0025: Incomplete pattern matches on this expression.

tests/fsharp/typecheck/sigs/neg110.bsl

@@ -1,2 +1,2 @@
-neg110.fs(5,3,5,15): typecheck error FS3242: This type does not inherit Attribute, it will not work correctly with other .NET languages.
 
+neg110.fs(5,3,5,15): typecheck error FS3242: This type does not inherit Attribute, it will not work correctly with other .NET languages.

tests/fsharp/typecheck/sigs/neg135.bsl

@@ -2,3 +2,7 @@
 neg135.fs(6,1,6,2): parse error FS0010: Unexpected symbol '}' in expression
 
 neg135.fs(4,5,4,11): parse error FS3122: Missing 'do' in 'while' expression. Expected 'while <expr> do <expr>'.
+
+neg135.fs(4,12,4,17): typecheck error FS0003: This value is not a function and cannot be applied.
+
+neg135.fs(4,12,4,17): typecheck error FS0003: This value is not a function and cannot be applied.

tests/fsharp/typecheck/sigs/neg64.vsbsl

@@ -1,2 +1,6 @@
 
 neg64.fsx(32,32,32,33): parse error FS0010: Unexpected symbol ')' in if/then/else expression
+
+neg64.fsx(32,17,32,31): typecheck error FS0001: All branches of an 'if' expression must return values implicitly convertible to the type of the first branch, which here is 'string'. This branch returns a value of type 'bool'.
+
+neg64.fsx(27,11,27,13): typecheck error FS0025: Incomplete pattern matches on this expression. For example, the value 'Horizontal (_, _)' may indicate a case not covered by the pattern(s).

tests/fsharp/typecheck/sigs/neg68.vsbsl

@@ -1,6 +1,26 @@
 
 neg68.fsx(71,46,71,47): parse error FS0010: Unexpected symbol ')' in binding. Expected incomplete structured construct at or before this point or other token.
 
+neg68.fsx(71,32,71,33): typecheck error FS0062: This construct is for ML compatibility. Consider using the '+' operator instead. This may require a type annotation to indicate it acts on strings. This message can be disabled using '--nowarn:62' or '#nowarn "62"'.
+
+neg68.fsx(71,30,71,46): typecheck error FS0001: This expression was expected to have type
+    'float'    
+but here has type
+    'string'    
+
+neg68.fsx(71,30,71,31): typecheck error FS1133: No constructors are available for the type 'm'
+
+neg68.fsx(71,43,71,44): typecheck error FS0062: This construct is for ML compatibility. Consider using the '+' operator instead. This may require a type annotation to indicate it acts on strings. This message can be disabled using '--nowarn:62' or '#nowarn "62"'.
+
+neg68.fsx(71,39,71,45): typecheck error FS0001: The type 'string' does not match the type 'int'
+
+neg68.fsx(71,39,71,41): typecheck error FS1133: No constructors are available for the type 'kg'
+
+neg68.fsx(71,44,71,45): typecheck error FS0001: This expression was expected to have type
+    'string'    
+but here has type
+    'int'    
+
 neg68.fsx(123,40,123,41): typecheck error FS0001: The type 'bool' does not match the type 'float<'u>'
 
 neg68.fsx(123,38,123,39): typecheck error FS0043: The type 'bool' does not match the type 'float<'u>'

tests/fsharp/typecheck/sigs/neg70.vsbsl

@@ -1,2 +1,14 @@
 
 neg70.fsx(109,64,109,65): parse error FS0010: Unexpected symbol ')' in binding. Expected incomplete structured construct at or before this point or other token.
+
+neg70.fsx(107,29,107,69): typecheck error FS0507: No accessible member or object constructor named 'Rectangle' takes 0 arguments. Note the call to this member also provides 1 named arguments.
+
+neg70.fsx(108,39,108,40): typecheck error FS0039: The value or constructor 'y' is not defined.
+
+neg70.fsx(110,18,110,43): typecheck error FS0041: No overloads match for method 'FillEllipse'.
+
+Known types of arguments: Brush * (int * bool * bool * bool)
+
+Available overloads:
+ - Graphics.FillEllipse(brush: Brush, rect: Rectangle) : unit // Argument 'rect' doesn't match
+ - Graphics.FillEllipse(brush: Brush, rect: RectangleF) : unit // Argument 'rect' doesn't match

tests/fsharp/typecheck/sigs/neg79.vsbsl

@@ -1,2 +1,6 @@
 
 neg79.fsx(31,32,31,33): parse error FS0010: Unexpected symbol ')' in if/then/else expression
+
+neg79.fsx(31,17,31,31): typecheck error FS0001: All branches of an 'if' expression must return values implicitly convertible to the type of the first branch, which here is 'string'. This branch returns a value of type 'bool'.
+
+neg79.fsx(26,11,26,13): typecheck error FS0025: Incomplete pattern matches on this expression. For example, the value 'Horizontal (_, _)' may indicate a case not covered by the pattern(s).

tests/fsharp/typecheck/sigs/neg80.vsbsl

@@ -1,2 +1,4 @@
 
 neg80.fsx(79,5,79,6): parse error FS0010: Unexpected symbol '|' in pattern matching
+
+neg80.fsx(79,7,79,28): typecheck error FS0026: This rule will never be matched

tests/fsharp/typecheck/sigs/neg82.vsbsl

@@ -26,4 +26,6 @@ To continue using non-conforming indentation, pass the '--strict-indentation-' f
 neg82.fsx(138,1,138,4): parse error FS0058: Unexpected syntax or possible incorrect indentation: this token is offside of context started at position (102:1). Try indenting this further.
 To continue using non-conforming indentation, pass the '--strict-indentation-' flag to the compiler, or set the language version to F# 7.
 
+neg82.fsx(76,11,76,13): typecheck error FS0025: Incomplete pattern matches on this expression. For example, the value 'Horizontal (_, _)' may indicate a case not covered by the pattern(s).
+
 neg82.fsx(93,5,93,7): typecheck error FS0039: The value, namespace, type or module 'sb' is not defined.

tests/fsharp/typecheck/sigs/neg83.vsbsl

@@ -8,3 +8,21 @@ neg83.fsx(13,2,13,5): parse error FS0058: Unexpected syntax or possible incorrec
 To continue using non-conforming indentation, pass the '--strict-indentation-' flag to the compiler, or set the language version to F# 7.
 
 neg83.fsx(16,1,16,1): parse error FS0010: Incomplete structured construct at or before this point in expression
+
+neg83.fsx(8,12,8,39): typecheck error FS0001: Type mismatch. Expecting a
+    '('a -> 'a) -> string -> 'b'    
+but given a
+    ''c list -> 'd list'    
+The type ''a list' does not match the type ''b -> 'b'
+
+neg83.fsx(8,12,8,39): typecheck error FS0001: Type mismatch. Expecting a
+    '('a -> 'a) -> string -> 'b'    
+but given a
+    ''c list -> 'd list'    
+The type ''a list' does not match the type ''c -> 'c'
+
+neg83.fsx(10,15,10,17): typecheck error FS3217: This expression is not a function and cannot be applied. Did you intend to access the indexer via 'expr[index]'?
+
+neg83.fsx(15,4,15,31): typecheck error FS0001: The type ''a list' does not match the type ''b -> 'b'
+
+neg83.fsx(15,4,15,31): typecheck error FS0001: The type ''a list' does not match the type ''c -> 'c'

tests/fsharp/typecheck/sigs/neg84.vsbsl

@@ -1,2 +1,4 @@
 
 neg84.fsx(11,1,11,1): parse error FS0010: Incomplete structured construct at or before this point in expression
+
+neg84.fsx(4,10,4,12): typecheck error FS0025: Incomplete pattern matches on this expression. For example, the value '[_]' may indicate a case not covered by the pattern(s).

tests/fsharp/typecheck/sigs/neg86.vsbsl

@@ -9,6 +9,13 @@ neg86.fsx(8,13,8,17): typecheck error FS3167: 'join' must be followed by 'in'. U
 
 neg86.fsx(9,21,9,22): typecheck error FS0039: The value or constructor 'e' is not defined.
 
+neg86.fsx(18,20,18,22): typecheck error FS3145: This is not a known query operator. Query operators are identifiers such as 'select', 'where', 'sortBy', 'thenBy', 'groupBy', 'groupValBy', 'join', 'groupJoin', 'sumBy' and 'averageBy', defined using corresponding methods on the 'QueryBuilder' type.
+
+neg86.fsx(18,20,18,22): typecheck error FS0039: The value or constructor 'op_Atin' is not defined. Maybe you want one of the following:
+   Option
+   option
+   Option
+
 neg86.fsx(23,13,23,17): typecheck error FS3097: Incorrect syntax for 'join'. Usage: join var in collection on (outerKey = innerKey). Note that parentheses are required after 'on'.
 
 neg86.fsx(28,13,28,17): typecheck error FS3097: Incorrect syntax for 'join'. Usage: join var in collection on (outerKey = innerKey). Note that parentheses are required after 'on'.