diff --git a/crates/oxc_semantic/src/checker/mod.rs b/crates/oxc_semantic/src/checker/mod.rs
index 13fadeb0012cd..5daee4afbdb95 100644
--- a/crates/oxc_semantic/src/checker/mod.rs
+++ b/crates/oxc_semantic/src/checker/mod.rs
@@ -17,8 +17,12 @@ pub fn check<'a>(node: &AstNode<'a>, ctx: &SemanticBuilder<'a>) {
     let kind = node.kind();
 
     match kind {
-        AstKind::Program(_) => {
+        AstKind::Program(program) => {
             js::check_duplicate_class_elements(ctx);
+            ts::check_stmts(&program.body, ctx);
+        }
+        AstKind::BlockStatement(block) => {
+            ts::check_stmts(&block.body, ctx);
         }
         AstKind::BindingIdentifier(ident) => {
             js::check_identifier(&ident.name, ident.span, node, ctx);
diff --git a/crates/oxc_semantic/src/checker/typescript.rs b/crates/oxc_semantic/src/checker/typescript.rs
index 4a35aae3ee2bd..0d8a63b066ecf 100644
--- a/crates/oxc_semantic/src/checker/typescript.rs
+++ b/crates/oxc_semantic/src/checker/typescript.rs
@@ -542,3 +542,32 @@ pub fn check_for_statement_left(left: &ForStatementLeft, is_for_in: bool, ctx: &
         }
     }
 }
+
+fn function_implementation_must_have_same_name_as_decl(span: Span) -> OxcDiagnostic {
+    OxcDiagnostic::error("Function implementation name must be the same as the declaration.")
+        .with_label(span)
+}
+
+pub fn check_stmts(stmts: &oxc_allocator::Vec<'_, Statement<'_>>, ctx: &SemanticBuilder<'_>) {
+    if !ctx.source_type.is_typescript_definition() {
+        for (a, b) in stmts.iter().map(Some).chain(vec![None, None]).tuple_windows() {
+            if let Some(Statement::FunctionDeclaration(a)) = a {
+                if !a.declare && a.body.is_none() {
+                    if let Some(Statement::FunctionDeclaration(b)) = b {
+                        if b.id.as_ref().map(|id| &id.name) != a.id.as_ref().map(|id| &id.name)
+                            && b.body.is_some()
+                        {
+                            ctx.error(function_implementation_must_have_same_name_as_decl(
+                                a.id.as_ref().map_or(a.span, |id| id.span),
+                            ));
+                        }
+                    } else {
+                        ctx.error(function_implementation_missing(
+                            a.id.as_ref().map_or(a.span, |id| id.span),
+                        ));
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/tasks/coverage/snapshots/parser_typescript.snap b/tasks/coverage/snapshots/parser_typescript.snap
index 9cbe6b1320bce..5d8e9b2c59507 100644
--- a/tasks/coverage/snapshots/parser_typescript.snap
+++ b/tasks/coverage/snapshots/parser_typescript.snap
@@ -3,13 +3,10 @@ commit: d85767ab
 parser_typescript Summary:
 AST Parsed     : 6494/6503 (99.86%)
 Positive Passed: 6483/6503 (99.69%)
-Negative Passed: 1275/5747 (22.19%)
+Negative Passed: 1294/5747 (22.52%)
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/ClassDeclaration24.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/ExportAssignment7.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/ExportAssignment8.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration3.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration4.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration6.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration7.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/InterfaceDeclaration8.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/abstractClassInLocalScopeIsAbstract.ts
@@ -101,7 +98,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assigningFun
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompat1.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatBug2.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatBug5.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatFunctionsWithOptionalArgs.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatInterfaceWithStringIndexSignature.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatWithOverloads.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/assignmentCompatability11.ts
@@ -220,10 +216,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOnClass.
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOnInstance.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloadViaElementAccessExpression.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloads1.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloads2.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloads3.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloads4.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callOverloads5.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callSignaturesShouldBeResolvedBeforeSpecialization.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callWithWrongNumberOfTypeArguments.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/callbackArgsDifferByOptionality.ts
@@ -319,7 +311,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classMemberI
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classMemberInitializerWithLamdaScoping4.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classMergedWithInterfaceMultipleBasesNoError.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classOrder2.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classOverloadForFunction2.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classPropertyErrorOnNameOnly.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classSideInheritance1.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/classSideInheritance2.ts
@@ -875,10 +866,7 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionCall
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionCallOnConstrainedTypeVariable.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionExpressionShadowedByParams.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloadAmbiguity1.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloadImplementationOfWrongName.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloadImplementationOfWrongName2.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads1.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads11.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads17.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads18.ts
@@ -887,7 +875,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOver
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads20.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads27.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads29.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads3.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads34.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads37.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/functionOverloads4.ts
@@ -1886,7 +1873,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/spreadInvali
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/spreadOfParamsFromGeneratorMakesRequiredParams.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/spyComparisonChecking.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/staticAsIdentifier.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/staticClassMemberError.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/staticInstanceResolution4.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/staticInstanceResolution5.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/staticMemberExportAccess.ts
@@ -3280,7 +3266,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalM
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/fixSignatureCaching.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/functionImplementationErrors.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/functionImplementations.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/functionNameConflicts.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/functionOverloadCompatibilityWithVoid01.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/functionOverloadErrors.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/functions/parameterInitializersForwardReferencing.2.ts
@@ -3747,9 +3732,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ec
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration1.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration2.d.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration2.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration3.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration4.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration6.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration7.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/Generics/parserAmbiguity1.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/Generics/parserAmbiguity2.ts
@@ -3796,7 +3778,6 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ec
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/MemberVariableDeclarations/parserMemberVariableDeclaration3.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration1.d.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration1.ts
-Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration10.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration2.d.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration3.ts
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration4.d.ts
@@ -4923,6 +4904,27 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ╰────
   help: Did you mean `readonly`?
 
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/FunctionDeclaration3.ts:1:10]
+ 1 │ function foo();
+   ·          ───
+   ╰────
+
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/compiler/FunctionDeclaration4.ts:1:10]
+ 1 │ function foo();
+   ·          ───
+ 2 │ function bar() { }
+   ╰────
+
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/compiler/FunctionDeclaration6.ts:2:14]
+ 1 │ {
+ 2 │     function foo();
+   ·              ───
+ 3 │     function bar() { }
+   ╰────
+
   × A parameter property is only allowed in a constructor implementation.
    ╭─[typescript/tests/cases/compiler/MemberAccessorDeclaration15.ts:2:12]
  1 │ class C {
@@ -5314,6 +5316,13 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ·         ─────
    ╰────
 
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/assignmentCompatFunctionsWithOptionalArgs.ts:1:10]
+ 1 │ function foo(x: { id: number; name?: string; }): void;
+   ·          ───
+ 2 │ foo({ id: 1234 });                 // Ok
+   ╰────
+
   × Cannot assign to this expression
    ╭─[typescript/tests/cases/compiler/assignmentToParenthesizedExpression1.ts:2:2]
  1 │ var x;
@@ -5897,6 +5906,38 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ·       ─
    ╰────
 
+  × Function implementation name must be the same as the declaration.
+    ╭─[typescript/tests/cases/compiler/callOverloads2.ts:9:10]
+  8 │ 
+  9 │ function Foo(); // error
+    ·          ───
+ 10 │ 
+    ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/callOverloads3.ts:2:10]
+ 1 │ function Foo():Foo; // error
+ 2 │ function Foo(s:string):Foo; // error
+   ·          ───
+ 3 │ class Foo { // error
+   ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/callOverloads4.ts:2:10]
+ 1 │ function Foo():Foo; // error
+ 2 │ function Foo(s:string):Foo; // error
+   ·          ───
+ 3 │ class Foo { // error
+   ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/callOverloads5.ts:2:10]
+ 1 │ function Foo():Foo; // error
+ 2 │ function Foo(s:string):Foo; // error
+   ·          ───
+ 3 │ class Foo { // error
+   ╰────
+
   × Unexpected token
    ╭─[typescript/tests/cases/compiler/cannotInvokeNewOnErrorExpression.ts:5:22]
  4 │ }
@@ -6011,6 +6052,13 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ·           ╰── It can not be redeclared here
    ╰────
 
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/classOverloadForFunction2.ts:1:10]
+ 1 │ function bar(): string;
+   ·          ───
+ 2 │ class bar {}
+   ╰────
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
     ╭─[typescript/tests/cases/compiler/classUpdateTests.ts:93:9]
  92 │     constructor() {
@@ -8254,6 +8302,41 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
  3 │   function f() {
    ╰────
 
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/compiler/functionOverloadImplementationOfWrongName.ts:2:10]
+ 1 │ function foo(x);
+ 2 │ function foo(x, y);
+   ·          ───
+ 3 │ function bar() { }
+   ╰────
+
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/compiler/functionOverloadImplementationOfWrongName2.ts:1:10]
+ 1 │ function foo(x);
+   ·          ───
+ 2 │ function bar() { }
+   ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/functionOverloadImplementationOfWrongName2.ts:3:10]
+ 2 │ function bar() { }
+ 3 │ function foo(x, y);
+   ·          ───
+   ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/functionOverloads1.ts:1:10]
+ 1 │ function foo();
+   ·          ───
+ 2 │ 1+1;
+   ╰────
+
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/compiler/functionOverloads3.ts:1:10]
+ 1 │ function foo():string;
+   ·          ───
+   ╰────
+
   × Function implementation is missing or not immediately following the declaration.
    ╭─[typescript/tests/cases/compiler/functionOverloadsOutOfOrder.ts:6:13]
  5 │     }
@@ -11979,6 +12062,14 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ╰────
   help: A `break` statement can only be used within an enclosing iteration or switch statement.
 
+  × Function implementation is missing or not immediately following the declaration.
+    ╭─[typescript/tests/cases/compiler/staticClassMemberError.ts:9:10]
+  8 │ // just want to make sure this one doesn't crash the compiler
+  9 │ function Foo();
+    ·          ───
+ 10 │ class Foo {
+    ╰────
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[typescript/tests/cases/compiler/staticClassProps.ts:4:15]
  3 │     public foo() {
@@ -19714,6 +19805,14 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ·                ╰── `,` expected
    ╰────
 
+  × Function implementation name must be the same as the declaration.
+    ╭─[typescript/tests/cases/conformance/functions/functionNameConflicts.ts:23:10]
+ 22 │ 
+ 23 │ function over();
+    ·          ────
+ 24 │ function overrr() {
+    ╰────
+
   × A rest parameter must be last in a parameter list
     ╭─[typescript/tests/cases/conformance/functions/functionOverloadErrorsSyntax.ts:9:25]
   8 │ //Function overload signature with rest param followed by non-optional parameter
@@ -21367,6 +21466,27 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    ·    ─────────
    ╰────
 
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration3.ts:1:10]
+ 1 │ function foo();
+   ·          ───
+   ╰────
+
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration4.ts:1:10]
+ 1 │ function foo();
+   ·          ───
+ 2 │ function bar() { }
+   ╰────
+
+  × Function implementation name must be the same as the declaration.
+   ╭─[typescript/tests/cases/conformance/parser/ecmascript5/FunctionDeclarations/parserFunctionDeclaration6.ts:2:14]
+ 1 │ {
+ 2 │     function foo();
+   ·              ───
+ 3 │     function bar() { }
+   ╰────
+
   × Unexpected token
    ╭─[typescript/tests/cases/conformance/parser/ecmascript5/Fuzz/parser0_004152.ts:2:45]
  1 │ export class Game {
@@ -21755,6 +21875,13 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/private
    · ────
    ╰────
 
+  × Function implementation is missing or not immediately following the declaration.
+   ╭─[typescript/tests/cases/conformance/parser/ecmascript5/ModuleDeclarations/parserModuleDeclaration10.ts:2:10]
+ 1 │ function data(): string;
+ 2 │ function next(): string;
+   ·          ────
+   ╰────
+
   × Expected `(` but found `;`
    ╭─[typescript/tests/cases/conformance/parser/ecmascript5/ObjectTypes/parserObjectType5.ts:3:7]
  2 │    A: B