diff --git a/src/Compiler/SyntaxTree/LexFilter.fs b/src/Compiler/SyntaxTree/LexFilter.fs
index c90539ad3f8..1c5b635498d 100644
--- a/src/Compiler/SyntaxTree/LexFilter.fs
+++ b/src/Compiler/SyntaxTree/LexFilter.fs
@@ -49,7 +49,7 @@ type Context =
     | CtxtTypeDefns of Position    // 'type <here> =', not removed when we find the "="
 
     | CtxtNamespaceHead of Position * token
-    | CtxtModuleHead of Position * token * LexingModuleAttributes
+    | CtxtModuleHead of Position * token * LexingModuleAttributes * isNested: bool
     | CtxtMemberHead of Position
     | CtxtMemberBody of Position
     // If bool is true then this is "whole file"
@@ -68,7 +68,7 @@ type Context =
 
     member c.StartPos =
         match c with
-        | CtxtNamespaceHead (p, _) | CtxtModuleHead (p, _, _) | CtxtException p | CtxtModuleBody (p, _) | CtxtNamespaceBody p
+        | CtxtNamespaceHead (p, _) | CtxtModuleHead (p, _, _, _) | CtxtException p | CtxtModuleBody (p, _) | CtxtNamespaceBody p
         | CtxtLetDecl (_, p) | CtxtDo p | CtxtInterfaceHead p | CtxtTypeDefns p | CtxtParen (_, p) | CtxtMemberHead p | CtxtMemberBody p
         | CtxtWithAsLet p
         | CtxtWithAsAugment p
@@ -1393,6 +1393,9 @@ type LexFilterImpl (
             | CtxtSeqBlock(_, _, AddOneSidedBlockEnd) ->
                 Some (ORIGHT_BLOCK_END(getLastTokenEndRange ()))
 
+            | CtxtModuleHead(isNested = true) ->
+                Some OBLOCKSEP
+
             | _ ->
                 None
 
@@ -1598,11 +1601,11 @@ type LexFilterImpl (
         //  Otherwise it's a 'head' module declaration, so ignore it
 
         //  Here prevToken is either 'module', 'rec', 'global' (invalid), '.', or ident, because we skip attribute tokens and access modifier tokens
-        | _, CtxtModuleHead (moduleTokenPos, prevToken, lexingModuleAttributes) :: rest ->
+        | _, CtxtModuleHead (moduleTokenPos, prevToken, lexingModuleAttributes, isNested) :: rest ->
             match prevToken, token with
             | _, GREATER_RBRACK when lexingModuleAttributes = LexingModuleAttributes
                                      && moduleTokenPos.Column < tokenStartPos.Column ->
-                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, prevToken, NotLexingModuleAttributes))
+                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, prevToken, NotLexingModuleAttributes, isNested))
                 returnToken tokenLexbufState token
             | _ when lexingModuleAttributes = LexingModuleAttributes
                      && moduleTokenPos.Column < tokenStartPos.Column ->
@@ -1612,10 +1615,10 @@ type LexFilterImpl (
             | MODULE, GLOBAL
             | (MODULE | REC | DOT), (REC | IDENT _)
             | IDENT _, DOT when moduleTokenPos.Column < tokenStartPos.Column ->
-                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, token, NotLexingModuleAttributes))
+                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, token, NotLexingModuleAttributes, isNested))
                 returnToken tokenLexbufState token
             | MODULE, LBRACK_LESS when moduleTokenPos.Column < tokenStartPos.Column  ->
-                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, prevToken, LexingModuleAttributes))
+                replaceCtxt tokenTup (CtxtModuleHead (moduleTokenPos, prevToken, LexingModuleAttributes, isNested))
                 returnToken tokenLexbufState token
             | _, (EQUALS | COLON) ->
                 if debug then dprintf "CtxtModuleHead: COLON/EQUALS, pushing CtxtModuleBody and CtxtSeqBlock\n"
@@ -1643,7 +1646,7 @@ type LexFilterImpl (
                     // and we've encountered declarations below
                     if debug then dprintf "CtxtModuleHead: not start of file, popping CtxtModuleHead\n"
                     popCtxt()
-                    reprocessWithoutBlockRule()
+                    insertTokenFromPrevPosToCurrentPos OBLOCKSEP
 
         //  Offside rule for SeqBlock.
         //      f x
@@ -1972,7 +1975,8 @@ type LexFilterImpl (
         | MODULE, _ :: _ ->
             insertComingSoonTokens("MODULE", MODULE_COMING_SOON, MODULE_IS_HERE)
             if debug then dprintf "MODULE: entering CtxtModuleHead, awaiting EQUALS to go to CtxtSeqBlock (%a)\n" outputPos tokenStartPos
-            pushCtxt tokenTup (CtxtModuleHead (tokenStartPos, token, NotLexingModuleAttributes))
+            let isNested = match offsideStack with | [ CtxtSeqBlock _ ] -> false | _ -> true
+            pushCtxt tokenTup (CtxtModuleHead (tokenStartPos, token, NotLexingModuleAttributes, isNested))
             pool.Return tokenTup
             hwTokenFetch useBlockRule
 
diff --git a/src/Compiler/pars.fsy b/src/Compiler/pars.fsy
index e35eb962f6d..0509f867c73 100644
--- a/src/Compiler/pars.fsy
+++ b/src/Compiler/pars.fsy
@@ -521,6 +521,12 @@ moduleIntro:
         let mModule = rhs parseState 1
         mModule, $4, $5.LongIdent, $3, $2 }
 
+  | moduleKeyword opt_attributes opt_access opt_rec OBLOCKSEP
+      { if not (isNil $2) then
+            parseState.LexBuffer.CheckLanguageFeatureAndRecover LanguageFeature.AttributesToRightOfModuleKeyword (rhs parseState 4)
+        let mModule = rhs parseState 1
+        mModule, $4, [], $3, $2 }
+
 
 /* The start of a namespace declaration */
 namespaceIntro:
diff --git a/tests/fsharp/typecheck/sigs/neg41.bsl b/tests/fsharp/typecheck/sigs/neg41.bsl
index 18115064cc9..122351ab76c 100644
--- a/tests/fsharp/typecheck/sigs/neg41.bsl
+++ b/tests/fsharp/typecheck/sigs/neg41.bsl
@@ -1,2 +1,2 @@
 
-neg41.fs(3,1,3,5): parse error FS0010: Unexpected keyword 'type' in definition. Expected '=' or other token.
+neg41.fs(2,20,3,1): parse error FS0010: Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/fsharp/typecheck/sigs/neg42.bsl b/tests/fsharp/typecheck/sigs/neg42.bsl
index 3dec6d2329b..9f2bba6bf0d 100644
--- a/tests/fsharp/typecheck/sigs/neg42.bsl
+++ b/tests/fsharp/typecheck/sigs/neg42.bsl
@@ -1,2 +1,2 @@
 
-neg42.fsi(3,1,3,5): parse error FS0010: Unexpected keyword 'type' in signature file. Expected ':', '=' or other token.
+neg42.fsi(2,20,3,1): parse error FS0010: Incomplete structured construct at or before this point in signature file. Expected ':', '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs
new file mode 100644
index 00000000000..90d76105dbc
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs	
@@ -0,0 +1,5 @@
+module Module
+
+module A
+
+()
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs.bsl
new file mode 100644
index 00000000000..44ab73f81ad
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 03.fs.bsl	
@@ -0,0 +1,20 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 03.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false, [], false, (3,0--3,8),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None });
+           Expr (Const (Unit, (5,0--5,2)), (5,0--5,2))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--5,2), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(3,9)-(5,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs
new file mode 100644
index 00000000000..2f61714c416
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs	
@@ -0,0 +1,5 @@
+module Module
+
+module
+
+()
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs.bsl
new file mode 100644
index 00000000000..4208cc94225
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 04.fs.bsl	
@@ -0,0 +1,20 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 04.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--5,0)), false, [], false, (3,0--5,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None });
+           Expr (Const (Unit, (5,0--5,2)), (5,0--5,2))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--5,2), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(3,7)-(5,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs
new file mode 100644
index 00000000000..3d3602d9735
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs	
@@ -0,0 +1,5 @@
+module Module
+
+module rec
+
+()
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs.bsl
new file mode 100644
index 00000000000..53b4a1f12df
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 05.fs.bsl	
@@ -0,0 +1,20 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 05.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--5,0)), true, [], false, (3,0--5,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None });
+           Expr (Const (Unit, (5,0--5,2)), (5,0--5,2))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--5,2), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(3,11)-(5,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs
new file mode 100644
index 00000000000..20c697536eb
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs	
@@ -0,0 +1,5 @@
+module Module
+
+module rec A
+
+()
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs.bsl
new file mode 100644
index 00000000000..d6875779d2f
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 06.fs.bsl	
@@ -0,0 +1,20 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 06.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,12)), true, [], false, (3,0--3,12),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None });
+           Expr (Const (Unit, (5,0--5,2)), (5,0--5,2))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--5,2), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(3,13)-(5,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs
new file mode 100644
index 00000000000..c37b1641337
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs	
@@ -0,0 +1,6 @@
+module Module
+
+module A =
+    module
+
+2
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs.bsl
new file mode 100644
index 00000000000..569bdfe5811
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 07.fs.bsl	
@@ -0,0 +1,27 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 07.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false,
+              [NestedModule
+                 (SynComponentInfo
+                    ([], None, [], [],
+                     PreXmlDoc ((4,4), FSharp.Compiler.Xml.XmlDocCollector),
+                     false, None, (4,4--6,0)), false, [], false, (4,4--6,0),
+                  { ModuleKeyword = Some (4,4--4,10)
+                    EqualsRange = None })], false, (3,0--6,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = Some (3,9--3,10) });
+           Expr (Const (Int32 2, (6,0--6,1)), (6,0--6,1))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--6,1), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(6,0)-(6,1) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs
new file mode 100644
index 00000000000..c73c8b4320b
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs	
@@ -0,0 +1,6 @@
+module Module
+
+module A =
+    module B
+
+    2
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs.bsl
new file mode 100644
index 00000000000..1b6fcc1a41c
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 08.fs.bsl	
@@ -0,0 +1,27 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 08.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false,
+              [NestedModule
+                 (SynComponentInfo
+                    ([], None, [], [B],
+                     PreXmlDoc ((4,4), FSharp.Compiler.Xml.XmlDocCollector),
+                     false, None, (4,4--4,12)), false, [], false, (4,4--4,12),
+                  { ModuleKeyword = Some (4,4--4,10)
+                    EqualsRange = None });
+               Expr (Const (Int32 2, (6,4--6,5)), (6,4--6,5))], false,
+              (3,0--6,5), { ModuleKeyword = Some (3,0--3,6)
+                            EqualsRange = Some (3,9--3,10) })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--6,5), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,13)-(6,4) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs
new file mode 100644
index 00000000000..e5d48898ea2
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs	
@@ -0,0 +1,6 @@
+module Module
+
+module A =
+    module B =
+
+    2
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs.bsl
new file mode 100644
index 00000000000..ce79f7aba8d
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 09.fs.bsl	
@@ -0,0 +1,28 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 09.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false,
+              [NestedModule
+                 (SynComponentInfo
+                    ([], None, [], [B],
+                     PreXmlDoc ((4,4), FSharp.Compiler.Xml.XmlDocCollector),
+                     false, None, (4,4--4,12)), false, [], false, (4,4--4,14),
+                  { ModuleKeyword = Some (4,4--4,10)
+                    EqualsRange = Some (4,13--4,14) });
+               Expr (Const (Int32 2, (6,4--6,5)), (6,4--6,5))], false,
+              (3,0--6,5), { ModuleKeyword = Some (3,0--3,6)
+                            EqualsRange = Some (3,9--3,10) })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--6,5), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(6,4)-(6,5) parse error Possible incorrect indentation: this token is offside of context started at position (4:5). Try indenting this token further or using standard formatting conventions.
+(6,4)-(6,5) parse error Incomplete structured construct at or before this point in definition
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs
new file mode 100644
index 00000000000..136af483ef1
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs	
@@ -0,0 +1,6 @@
+module Module
+
+module A =
+    module
+
+    2
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs.bsl
new file mode 100644
index 00000000000..4605fc9a35d
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 10.fs.bsl	
@@ -0,0 +1,27 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 10.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false,
+              [NestedModule
+                 (SynComponentInfo
+                    ([], None, [], [],
+                     PreXmlDoc ((4,4), FSharp.Compiler.Xml.XmlDocCollector),
+                     false, None, (4,4--6,4)), false, [], false, (4,4--6,4),
+                  { ModuleKeyword = Some (4,4--4,10)
+                    EqualsRange = None });
+               Expr (Const (Int32 2, (6,4--6,5)), (6,4--6,5))], false,
+              (3,0--6,5), { ModuleKeyword = Some (3,0--3,6)
+                            EqualsRange = Some (3,9--3,10) })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--6,5), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,11)-(6,4) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs
new file mode 100644
index 00000000000..f1284331320
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs	
@@ -0,0 +1,5 @@
+module Module
+
+module
+
+A
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs.bsl
new file mode 100644
index 00000000000..181836a8b7f
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 11.fs.bsl	
@@ -0,0 +1,19 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 11.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--5,0)), false, [], false, (3,0--5,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None }); Expr (Ident A, (5,0--5,1))],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--5,1), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(3,7)-(5,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs
new file mode 100644
index 00000000000..a2fe094f382
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs	
@@ -0,0 +1,3 @@
+module Module
+
+module
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs.bsl
new file mode 100644
index 00000000000..eb79389bb5c
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 12.fs.bsl	
@@ -0,0 +1,19 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 12.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--4,0)), false, [], false, (3,0--4,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--4,0), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs
new file mode 100644
index 00000000000..9d2084ebc72
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs	
@@ -0,0 +1,3 @@
+module Module
+
+module A
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs.bsl
new file mode 100644
index 00000000000..c57a57743cb
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 13.fs.bsl	
@@ -0,0 +1,19 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 13.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false, [], false, (3,0--3,8),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--3,8), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs
new file mode 100644
index 00000000000..97b86766455
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs	
@@ -0,0 +1,3 @@
+module Module
+
+module A =
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs.bsl
new file mode 100644
index 00000000000..8417322a575
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 14.fs.bsl	
@@ -0,0 +1,20 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 14.fs", false,
+      QualifiedNameOfFile Module, [], [],
+      [SynModuleOrNamespace
+         ([Module], false, NamedModule,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false, [], false, (3,0--3,10),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = Some (3,9--3,10) })],
+          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
+          (1,0--3,10), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Possible incorrect indentation: this token is offside of context started at position (3:1). Try indenting this token further or using standard formatting conventions.
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs
new file mode 100644
index 00000000000..e8bc9fdc187
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs	
@@ -0,0 +1,3 @@
+namespace Ns
+
+module A =
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs.bsl
new file mode 100644
index 00000000000..bb23f859ec8
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 15.fs.bsl	
@@ -0,0 +1,19 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 15.fs", false,
+      QualifiedNameOfFile Nested module 15, [], [],
+      [SynModuleOrNamespace
+         ([Ns], false, DeclaredNamespace,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false, [], false, (3,0--3,10),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = Some (3,9--3,10) })], PreXmlDocEmpty, [], None,
+          (1,0--3,10), { LeadingKeyword = Namespace (1,0--1,9) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Possible incorrect indentation: this token is offside of context started at position (3:1). Try indenting this token further or using standard formatting conventions.
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs
new file mode 100644
index 00000000000..7debb3295b5
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs	
@@ -0,0 +1,3 @@
+namespace Ns
+
+module A
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs.bsl
new file mode 100644
index 00000000000..2ce127eef5d
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 16.fs.bsl	
@@ -0,0 +1,18 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 16.fs", false,
+      QualifiedNameOfFile Nested module 16, [], [],
+      [SynModuleOrNamespace
+         ([Ns], false, DeclaredNamespace,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [A],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--3,8)), false, [], false, (3,0--3,8),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None })], PreXmlDocEmpty, [], None, (1,0--3,8),
+          { LeadingKeyword = Namespace (1,0--1,9) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs
new file mode 100644
index 00000000000..4baf660a9b5
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs	
@@ -0,0 +1,3 @@
+namespace Ns
+
+module
diff --git a/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs.bsl b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs.bsl
new file mode 100644
index 00000000000..4e5dd1a1914
--- /dev/null
+++ b/tests/service/data/SyntaxTree/ModuleOrNamespace/Nested module 17.fs.bsl	
@@ -0,0 +1,18 @@
+ImplFile
+  (ParsedImplFileInput
+     ("/root/ModuleOrNamespace/Nested module 17.fs", false,
+      QualifiedNameOfFile Nested module 17, [], [],
+      [SynModuleOrNamespace
+         ([Ns], false, DeclaredNamespace,
+          [NestedModule
+             (SynComponentInfo
+                ([], None, [], [],
+                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
+                 None, (3,0--4,0)), false, [], false, (3,0--4,0),
+              { ModuleKeyword = Some (3,0--3,6)
+                EqualsRange = None })], PreXmlDocEmpty, [], None, (1,0--4,0),
+          { LeadingKeyword = Namespace (1,0--1,9) })], (true, true),
+      { ConditionalDirectives = []
+        CodeComments = [] }, set []))
+
+(4,0)-(4,0) parse error Incomplete structured construct at or before this point in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs b/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs
deleted file mode 100644
index 30cb557e092..00000000000
--- a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs
+++ /dev/null
@@ -1,5 +0,0 @@
-module A.B
-
-module C
-
-let a = ()
\ No newline at end of file
diff --git a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs.bsl b/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs.bsl
deleted file mode 100644
index 5ab8dedcebc..00000000000
--- a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleShouldBePresent.fs.bsl
+++ /dev/null
@@ -1,31 +0,0 @@
-ImplFile
-  (ParsedImplFileInput
-     ("/root/NestedModule/IncompleteNestedModuleShouldBePresent.fs", false,
-      QualifiedNameOfFile A.B, [], [],
-      [SynModuleOrNamespace
-         ([A; B], false, NamedModule,
-          [NestedModule
-             (SynComponentInfo
-                ([], None, [], [C],
-                 PreXmlDoc ((3,0), FSharp.Compiler.Xml.XmlDocCollector), false,
-                 None, (3,0--3,8)), false, [], false, (3,0--3,8),
-              { ModuleKeyword = Some (3,0--3,6)
-                EqualsRange = None });
-           Let
-             (false,
-              [SynBinding
-                 (None, Normal, false, false, [],
-                  PreXmlDoc ((5,0), FSharp.Compiler.Xml.XmlDocCollector),
-                  SynValData
-                    (None, SynValInfo ([], SynArgInfo ([], false, None)), None),
-                  Named (SynIdent (a, None), false, None, (5,4--5,5)), None,
-                  Const (Unit, (5,8--5,10)), (5,4--5,5), Yes (5,0--5,10),
-                  { LeadingKeyword = Let (5,0--5,3)
-                    InlineKeyword = None
-                    EqualsRange = Some (5,6--5,7) })], (5,0--5,10))],
-          PreXmlDoc ((1,0), FSharp.Compiler.Xml.XmlDocCollector), [], None,
-          (1,0--5,10), { LeadingKeyword = Module (1,0--1,6) })], (true, true),
-      { ConditionalDirectives = []
-        CodeComments = [] }, set []))
-
-(5,0)-(5,3) parse error Unexpected keyword 'let' or 'use' in definition. Expected '=' or other token.
diff --git a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleSigShouldBePresent.fsi.bsl b/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleSigShouldBePresent.fsi.bsl
index eafee5cf745..9c697d753d9 100644
--- a/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleSigShouldBePresent.fsi.bsl
+++ b/tests/service/data/SyntaxTree/NestedModule/IncompleteNestedModuleSigShouldBePresent.fsi.bsl
@@ -26,4 +26,4 @@ SigFile
       { ConditionalDirectives = []
         CodeComments = [] }, set []))
 
-(5,0)-(5,3) parse error Unexpected keyword 'val' in signature file. Expected ':', '=' or other token.
+(3,9)-(5,0) parse error Incomplete structured construct at or before this point in signature file. Expected ':', '=' or other token.