diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 8e1b779126..9311aa7cc2 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -104,6 +104,7 @@ namespace ts {
     function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
         let file: SourceFile;
         let options: CompilerOptions;
+        let languageVersion: ScriptTarget;
         let parent: Node;
         let container: Node;
         let blockScopeContainer: Node;
@@ -136,6 +137,7 @@ namespace ts {
         function bindSourceFile(f: SourceFile, opts: CompilerOptions) {
             file = f;
             options = opts;
+            languageVersion = getEmitScriptTarget(options);
             inStrictMode = !!file.externalModuleIndicator;
             classifiableNames = {};
 
@@ -149,6 +151,7 @@ namespace ts {
 
             file = undefined;
             options = undefined;
+            languageVersion = undefined;
             parent = undefined;
             container = undefined;
             blockScopeContainer = undefined;
@@ -1129,18 +1132,18 @@ namespace ts {
             // Provide specialized messages to help the user understand why we think they're in
             // strict mode.
             if (getContainingClass(node)) {
-                return Diagnostics.In_ES5_or_lower_function_declarations_are_not_allowed_in_block_scope_Class_definitions_are_automatically_in_strict_mode;
+                return Diagnostics.Function_declarations_are_not_allowed_inside_blocks_in_strict_mode_when_targeting_ES3_or_ES5_Class_definitions_are_automatically_in_strict_mode;
             }
 
             if (file.externalModuleIndicator) {
-                return Diagnostics.In_ES5_or_lower_function_declarations_are_not_allowed_in_block_scope_Modules_are_automatically_in_strict_mode;
+                return Diagnostics.Function_declarations_are_not_allowed_inside_blocks_in_strict_mode_when_targeting_ES3_or_ES5_Modules_are_automatically_in_strict_mode;
             }
 
-            return Diagnostics.In_ES5_or_lower_function_declarations_are_not_allowed_in_block_scope_in_strict_mode;
+            return Diagnostics.Function_declarations_are_not_allowed_inside_blocks_in_strict_mode_when_targeting_ES3_or_ES5;
         }
 
         function checkStrictModeFunctionDeclaration(node: FunctionDeclaration) {
-            if (getEmitScriptTarget(options) < ScriptTarget.ES6) {
+            if (languageVersion < ScriptTarget.ES6) {
                 // Report error if function is not top level function declaration
                 if (blockScopeContainer.kind !== SyntaxKind.SourceFile &&
                     blockScopeContainer.kind !== SyntaxKind.ModuleDeclaration &&
@@ -1671,7 +1674,7 @@ namespace ts {
             checkStrictModeFunctionName(<FunctionDeclaration>node);
             if (inStrictMode) {
                 checkStrictModeFunctionDeclaration(node);
-                bindBlockScopedDeclaration(node, SymbolFlags.Function, SymbolFlags.FunctionExcludes);
+                return bindBlockScopedDeclaration(node, SymbolFlags.Function, SymbolFlags.FunctionExcludes);
             }
             else {
                 return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Function, SymbolFlags.FunctionExcludes);
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index e8425afc09..b331241660 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -811,15 +811,15 @@
         "category": "Error",
         "code": 1249
     },
-    "In ES5 or lower, function declarations are not allowed in block scope in strict mode.": {
+    "Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'.": {
         "category": "Error",
         "code": 1250
     },
-    "In ES5 or lower, function declarations are not allowed in block scope. Class definitions are automatically in strict mode.": {
+    "Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Class definitions are automatically in strict mode.": {
         "category": "Error",
         "code": 1251
     },
-    "In ES5 or lower, function declarations are not allowed in block scope. Modules are automatically in strict mode.": {
+    "Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Modules are automatically in strict mode.": {
         "category": "Error",
         "code": 1252
     },
diff --git a/tests/baselines/reference/blockScopedFunctionDeclarationInStrictClass.errors.txt b/tests/baselines/reference/blockScopedFunctionDeclarationInStrictClass.errors.txt
index 685abb1d88..efedfd097a 100644
--- a/tests/baselines/reference/blockScopedFunctionDeclarationInStrictClass.errors.txt
+++ b/tests/baselines/reference/blockScopedFunctionDeclarationInStrictClass.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/blockScopedFunctionDeclarationInStrictClass.ts(4,22): error TS1251: In ES5 or lower, function declarations are not allowed in block scope. Class definitions are automatically in strict mode.
+tests/cases/compiler/blockScopedFunctionDeclarationInStrictClass.ts(4,22): error TS1251: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Class definitions are automatically in strict mode.
 tests/cases/compiler/blockScopedFunctionDeclarationInStrictClass.ts(7,9): error TS2304: Cannot find name 'foo'.
 
 
@@ -8,7 +8,7 @@ tests/cases/compiler/blockScopedFunctionDeclarationInStrictClass.ts(7,9): error
             if (true) {
                 function foo() { }
                          ~~~
-!!! error TS1251: In ES5 or lower, function declarations are not allowed in block scope. Class definitions are automatically in strict mode.
+!!! error TS1251: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Class definitions are automatically in strict mode.
                 foo(); // ok
             }
             foo(); // not ok
diff --git a/tests/baselines/reference/blockScopedFunctionDeclarationInStrictModule.errors.txt b/tests/baselines/reference/blockScopedFunctionDeclarationInStrictModule.errors.txt
index 7916cb93da..3f53ef24b5 100644
--- a/tests/baselines/reference/blockScopedFunctionDeclarationInStrictModule.errors.txt
+++ b/tests/baselines/reference/blockScopedFunctionDeclarationInStrictModule.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/blockScopedFunctionDeclarationInStrictModule.ts(2,14): error TS1252: In ES5 or lower, function declarations are not allowed in block scope. Modules are automatically in strict mode.
+tests/cases/compiler/blockScopedFunctionDeclarationInStrictModule.ts(2,14): error TS1252: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Modules are automatically in strict mode.
 tests/cases/compiler/blockScopedFunctionDeclarationInStrictModule.ts(6,10): error TS2304: Cannot find name 'foo'.
 
 
@@ -6,7 +6,7 @@ tests/cases/compiler/blockScopedFunctionDeclarationInStrictModule.ts(6,10): erro
     if (true) {
         function foo() { }
                  ~~~
-!!! error TS1252: In ES5 or lower, function declarations are not allowed in block scope. Modules are automatically in strict mode.
+!!! error TS1252: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'. Modules are automatically in strict mode.
         foo(); // ok
     }
     
diff --git a/tests/baselines/reference/blockScopedFunctionDeclarationStrictES5.errors.txt b/tests/baselines/reference/blockScopedFunctionDeclarationStrictES5.errors.txt
index e9c833b5d4..f945d0eacb 100644
--- a/tests/baselines/reference/blockScopedFunctionDeclarationStrictES5.errors.txt
+++ b/tests/baselines/reference/blockScopedFunctionDeclarationStrictES5.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/blockScopedFunctionDeclarationStrictES5.ts(3,14): error TS1250: In ES5 or lower, function declarations are not allowed in block scope in strict mode.
+tests/cases/compiler/blockScopedFunctionDeclarationStrictES5.ts(3,14): error TS1250: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'.
 tests/cases/compiler/blockScopedFunctionDeclarationStrictES5.ts(6,1): error TS2304: Cannot find name 'foo'.
 
 
@@ -7,7 +7,7 @@ tests/cases/compiler/blockScopedFunctionDeclarationStrictES5.ts(6,1): error TS23
     if (true) {
         function foo() { } // Error to declare function in block scope
                  ~~~
-!!! error TS1250: In ES5 or lower, function declarations are not allowed in block scope in strict mode.
+!!! error TS1250: Function declarations are not allowed inside blocks in strict mode when targeting 'ES3' or 'ES5'.
         foo(); // This call should be ok
     }
     foo(); // Error to find name foo