Nested arrows with same-named untyped parameters can be instantiated

tslang/lib/TypeScript/MLIRGenImpl.h

@@ -2717,10 +2717,14 @@ class MLIRGenImpl
         return mlir::StringRef(ss.str()).copy(stringAllocator);        
     }
 
-    mlir::StringRef getParameterGenericTypeName(std::string name) {
-        mlir::StringRef typeParamNamePtr;
+    // The type an untyped parameter makes its function generic in. It is named after the function
+    // too (its position): named after the parameter alone, the `x` of an arrow inside another arrow
+    // with an `x` had the outer one's type, so instantiating the outer arrow bound the inner one's
+    // type as well, and the inner arrow could no longer be instantiated.
+    mlir::StringRef getParameterGenericTypeName(std::string name, SignatureDeclarationBase signatureDeclarationBase) {
+        auto pos = signatureDeclarationBase->pos.textPos > 0 ? signatureDeclarationBase->pos.textPos : signatureDeclarationBase->pos.pos;
         std::stringstream ss;
-        ss << "TGenParam_" << name;
+        ss << "TGenParam_" << name << "_" << pos;
         return mlir::StringRef(ss.str()).copy(stringAllocator);
     }
 
@@ -10727,7 +10731,7 @@ class MLIRGenImpl
                         namePtr = getArgumentName(index);
                     }                    
 
-                    auto typeParamNamePtr = getParameterGenericTypeName(namePtr.str());      
+                    auto typeParamNamePtr = getParameterGenericTypeName(namePtr.str(), signatureDeclarationBase);      
                     auto &typeParameters = signatureDeclarationBase->typeParameters;
                     auto found = std::find_if(typeParameters.begin(), typeParameters.end(),
                                             [&](auto &paramItem) { return MLIRHelper::getName( paramItem->name) == typeParamNamePtr; });
@@ -10802,7 +10806,7 @@ class MLIRGenImpl
                     namePtr = getArgumentName(index);
                 }                    
 
-                auto typeParamNamePtr = getParameterGenericTypeName(namePtr.str());      
+                auto typeParamNamePtr = getParameterGenericTypeName(namePtr.str(), signatureDeclarationBase);      
                 auto typeParam = std::make_shared<TypeParameterDOM>(typeParamNamePtr.str());
                 auto result = zipTypeParameterWithArgument(
                     location, genContext.typeParamsWithArgs, typeParam, type, false, genContext);

tslang/test/tester/CMakeLists.txt

@@ -292,6 +292,7 @@ tslang_add_test(NAME test-compile-00-funcs-generic-typeof COMMAND test-runner "$
 tslang_add_test(NAME test-compile-00-funcs-generic-arrow COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_generic_arrow.ts")
 tslang_add_test(NAME test-compile-00-funcs-generic-iterator COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_generic_iterator.ts")
 tslang_add_test(NAME test-compile-00-funcs-typeless-function-as-generic COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_typeless_function_as_generic.ts")
+tslang_add_test(NAME test-compile-00-nested-implicit-generics COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00nested_implicit_generics.ts")
 tslang_add_test(NAME test-compile-01-funcs-generic-iterator COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/01funcs_generic_iterator.ts")
 tslang_add_test(NAME test-compile-02-funcs-generic-iterator COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/02funcs_generic_iterator.ts")
 tslang_add_test(NAME test-compile-00-funcs-typed-generic-iterator COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_typed_generic_iterator.ts")
@@ -810,6 +811,7 @@ tslang_add_test(NAME test-jit-01-funcs-generic COMMAND test-runner -jit "${PROJE
 tslang_add_test(NAME test-jit-00-funcs-generic-typeof COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_generic_with_typeof.ts")
 tslang_add_test(NAME test-jit-00-funcs-generic-arrow COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_generic_arrow.ts")
 tslang_add_test(NAME test-jit-00-funcs-typeless-function-as-generic COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_typeless_function_as_generic.ts")
+tslang_add_test(NAME test-jit-00-nested-implicit-generics COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00nested_implicit_generics.ts")
 tslang_add_test(NAME test-jit-00-funcs-generic-iterator COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00funcs_generic_iterator.ts")
 tslang_add_test(NAME test-jit-01-funcs-generic-iterator COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/01funcs_generic_iterator.ts")
 tslang_add_test(NAME test-jit-02-funcs-generic-iterator COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/02funcs_generic_iterator.ts")
@@ -1831,6 +1833,7 @@ set(TSLANG_CORPUS
     00funcs_nesting.ts
     00funcs_typed_generic_iterator.ts
     00funcs_typeless_function_as_generic.ts
+    00nested_implicit_generics.ts
     00funcs_vararg.ts
     00function_overloads.ts
     00gc_allocations_distinct.ts

tslang/test/tester/tests/00nested_implicit_generics.ts

@@ -0,0 +1,43 @@
+// An arrow with an untyped parameter inside another one with a parameter of the same name, which
+// captures a variable of the function around both, failed to compile: "can't instantiate function
+// ... not all generic types can be identified". Each untyped parameter makes its arrow generic in
+// a type named after the parameter, so the inner `x`'s type had the same name as the outer `x`'s,
+// and instantiating the outer arrow bound the inner one's type too.
+
+function render(screenWidth: number, screenHeight: number) {
+    const getPoint = (x, y) => {
+        const recenterX = x => (x - (screenWidth / 2.0)) / 2.0 / screenWidth;
+        const recenterY = y => -(y - (screenHeight / 2.0)) / 2.0 / screenHeight;
+        return recenterX(x) + recenterY(y);
+    };
+
+    assert(getPoint(512, 384) == 0, "getPoint(512, 384)");
+    assert(getPoint(1024, 768) == 0, "getPoint(1024, 768)");
+    const v = getPoint(300, 200);
+    assert(v - 0.016276 < 0.0001 && v - 0.016276 > -0.0001, "getPoint(300, 200)");
+}
+
+function untypedOuter(w, h) {
+    const add = (x, y) => {
+        const shift = x => x + w;
+        return shift(x) + y + h;
+    };
+
+    return add(1, 2);
+}
+
+function sameNameNoCapture() {
+    const outer = (x) => {
+        const inner = x => x * 2;
+        return inner(x) + 1;
+    };
+
+    return outer(5);
+}
+
+function main() {
+    render(1024, 768);
+    assert(untypedOuter(10, 100) == 113, "untypedOuter");
+    assert(sameNameNoCapture() == 11, "sameNameNoCapture");
+    print("done.");
+}