[move-compiler-v2] clean up a few remaining issues in lambda parser/f…

…ront-end code (#15365)

- Distinguish between "not supported" and "not implemented" for lambda features.
- Add a test case to illustrate the function name aliasing issue ([Bug][move-compiler-v2] visible function names shadow local variables with same name in function calls #15360), but changed other tests here to avoid it.
- Remove Constraint::NoFunction as it's too broad.
- Make sure there are still errors for all planned unsupported cases
- Fix LambdaLifter case for bound free variable without copy.
- Refine lambda test cases to make _ok versions that compile up to "not implemented" errors.

third_party/move/move-compiler-v2/src/bytecode_generator.rs

@@ -2,6 +2,7 @@
 // Parts of the project are originally copyright © Meta Platforms, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
+use crate::{experiments::Experiment, Options};
 use codespan_reporting::diagnostic::Severity;
 use ethnum::U256;
 use itertools::Itertools;
@@ -324,6 +325,14 @@ impl<'env> Generator<'env> {
         let loc = env.get_node_loc(id);
         env.diag(severity, &loc, msg.as_ref())
     }
+
+    fn check_if_lambdas_enabled(&self) -> bool {
+        let options = self
+            .env()
+            .get_extension::<Options>()
+            .expect("Options is available");
+        options.experiment_on(Experiment::LAMBDA_VALUES)
+    }
 }
 
 // ======================================================================================
@@ -480,14 +489,23 @@ impl<'env> Generator<'env> {
                 self.emit_with(*id, |attr| Bytecode::SpecBlock(attr, spec));
             },
             // TODO(LAMBDA)
-            ExpData::Lambda(id, _, _, _, _) => self.error(
+            ExpData::Lambda(id, _, _, _, _) =>
+                self.error(
                 *id,
-                "Function-typed values not yet supported except as parameters to calls to inline functions",
+                if self.check_if_lambdas_enabled() {
+                    "Function-typed values not yet implemented except as parameters to calls to inline functions"
+                } else {
+                    "Function-typed values not yet supported except as parameters to calls to inline functions"
+                }
             ),
             // TODO(LAMBDA)
             ExpData::Invoke(id, _exp, _) => self.error(
                 *id,
-                "Calls to function values other than inline function parameters not yet supported",
+                if self.check_if_lambdas_enabled() {
+                    "Calls to function values other than inline function parameters not yet implemented"
+                } else {
+                    "Calls to function values other than inline function parameters not yet supported"
+                }
             ),
             ExpData::Quant(id, _, _, _, _, _) => {
                 self.internal_error(*id, "unsupported specification construct")
@@ -564,10 +582,16 @@ impl<'env> Generator<'env> {
                     Constant::Bool(false)
                 }
             },
+            // TODO(LAMBDA)
             Value::Function(_mid, _fid) => {
                 self.error(
                     id,
-                    "Function-typed values not yet supported except as parameters to calls to inline functions");
+                    if self.check_if_lambdas_enabled() {
+                        "Function-typed values not yet implemented except as parameters to calls to inline functions"
+                    } else {
+                        "Function-typed values not yet supported except as parameters to calls to inline functions"
+                    }
+                );
                 Constant::Bool(false)
             },
         }
@@ -794,7 +818,11 @@ impl<'env> Generator<'env> {
             // TODO(LAMBDA)
             Operation::EarlyBind => self.error(
                 id,
-                "Function-typed values not yet supported except as parameters to calls to inline functions",
+                if self.check_if_lambdas_enabled() {
+                    "Function-typed values not yet implemented except as parameters to calls to inline functions"
+                } else {
+                    "Function-typed values not yet supported except as parameters to calls to inline functions"
+                },
             ),
             Operation::TestVariants(mid, sid, variants) => {
                 self.gen_test_variants(targets, id, mid.qualified(*sid), variants, args)

third_party/move/move-compiler-v2/src/env_pipeline/lambda_lifter.rs

@@ -739,7 +739,7 @@ impl<'a> ExpRewriterFunctions for LambdaLifter<'a> {
             env.error(
                 &loc,
                 // TODO(LAMBDA)
-                "Lambdas expressions with `store` ability currently may only be a simple call to an existing `public` function.  This lambda expression requires defining a `public` helper function, which is not yet supported."
+                "The body of a lambdas expression with `store` ability currently must be a simple call to an existing `public` function, with lambda params the same as the *final* arguments to the function call."
             );
             return None;
         };

third_party/move/move-compiler-v2/src/file_format_generator/module_generator.rs

@@ -372,7 +372,7 @@ impl ModuleGenerator {
                 ctx.error(
                     loc,
                     format!(
-                        "Unexpected type: {}",
+                        "Unimplemented type: {}",
                         ty.display(&ctx.env.get_type_display_ctx())
                     ),
                 );

third_party/move/move-compiler-v2/tests/checking/inlining/function_name_shadowing.exp

@@ -0,0 +1,66 @@
+
+Diagnostics:
+warning: Unused parameter `f`. Consider removing or prefixing with an underscore: `_f`
+   ┌─ tests/checking/inlining/function_name_shadowing.move:20:28
+   │
+20 │     public inline fun quux(f:|u64, u64|u64, g:|u64|u64, i:|u8|u8, a: u64, b: u64): u64 {
+   │                            ^
+
+warning: Unused parameter `g`. Consider removing or prefixing with an underscore: `_g`
+   ┌─ tests/checking/inlining/function_name_shadowing.move:20:45
+   │
+20 │     public inline fun quux(f:|u64, u64|u64, g:|u64|u64, i:|u8|u8, a: u64, b: u64): u64 {
+   │                                             ^
+
+warning: Unused parameter `i`. Consider removing or prefixing with an underscore: `_i`
+   ┌─ tests/checking/inlining/function_name_shadowing.move:20:57
+   │
+20 │     public inline fun quux(f:|u64, u64|u64, g:|u64|u64, i:|u8|u8, a: u64, b: u64): u64 {
+   │                                                         ^
+
+// -- Model dump before bytecode pipeline
+module 0x42::OtherModule {
+    public fun g(a: u64,b: u64): u64 {
+        Add<u64>(a, b)
+    }
+    public fun h(a: u64,b: u64): u64 {
+        Add<u64>(Mul<u64>(2, a), b)
+    }
+} // end 0x42::OtherModule
+module 0x42::Test {
+    use 0x42::OtherModule::{g}; // resolved as: 0x42::OtherModule
+    public fun f(a: u64,b: u64): u64 {
+        Mul<u64>(a, b)
+    }
+    public inline fun quux(f: |(u64, u64)|u64,g: |u64|u64,i: |u8|u8,a: u64,b: u64): u64 {
+        Mul<u64>(Mul<u64>(Test::f(a, b), OtherModule::g(a, b)), OtherModule::h(a, b))
+    }
+    public fun test_shadowing(): u64 {
+        Mul<u64>(Mul<u64>(Test::f(10, 2), OtherModule::g(10, 2)), OtherModule::h(10, 2))
+    }
+} // end 0x42::Test
+
+// -- Sourcified model before bytecode pipeline
+module 0x42::OtherModule {
+    public fun g(a: u64, b: u64): u64 {
+        a + b
+    }
+    public fun h(a: u64, b: u64): u64 {
+        2 * a + b
+    }
+}
+module 0x42::Test {
+    use 0x42::OtherModule;
+    public fun f(a: u64, b: u64): u64 {
+        a * b
+    }
+    public inline fun quux(f: |(u64, u64)|u64, g: |u64|u64, i: |u8|u8, a: u64, b: u64): u64 {
+        f(a, b) * OtherModule::g(a, b) * OtherModule::h(a, b)
+    }
+    public fun test_shadowing(): u64 {
+        f(10, 2) * OtherModule::g(10, 2) * OtherModule::h(10, 2)
+    }
+}
+
+
+============ bytecode verification succeeded ========

third_party/move/move-compiler-v2/tests/checking/inlining/function_name_shadowing.move

@@ -0,0 +1,30 @@
+//# publish
+module 0x42::OtherModule {
+    public fun g(a: u64, b: u64): u64 {
+        a + b
+    }
+
+    public fun h(a: u64, b: u64): u64 {
+        2 * a + b
+    }
+}
+
+//# publish
+module 0x42::Test {
+    use 0x42::OtherModule::g;
+
+    public fun f(a: u64, b: u64): u64 {
+        a * b
+    }
+
+    public inline fun quux(f:|u64, u64|u64, g:|u64|u64, i:|u8|u8, a: u64, b: u64): u64 {
+        use 0x42::OtherModule::h;
+        f(a, b) * g(a, b) * h(a, b)
+    }
+
+    public fun test_shadowing(): u64 {
+        quux(|a, b| a - b, |a| a + 2, |b| 255u8-b, 10, 2)
+    }
+}
+
+//# run 0x42::Test::test_shadowing

third_party/move/move-compiler-v2/tests/checking/typing/lambda.exp

@@ -48,11 +48,3 @@ error: tuple type `()` is not allowed as a type argument (type was inferred)
    │                                     ^
    │
    = required by instantiating type parameter `T` of function `foreach`
-
-error: function type `|u64|u64` is not allowed as a field type
-   ┌─ tests/checking/typing/lambda.move:81:12
-   │
-81 │         f: |u64|u64, // expected lambda not allowed
-   │            ^^^^^^^^
-   │
-   = required by declaration of field `f`

third_party/move/move-compiler-v2/tests/checking/typing/lambda_typed.exp

@@ -35,11 +35,3 @@ error: cannot pass `|&u64|u64 with copy+store` to a function which expects argum
    │
 73 │         foreach(&v, |e: &u64| { sum = sum + *e; *e }) // expected to have wrong result type of lambda
    │                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: function type `|u64|u64` is not allowed as a field type
-   ┌─ tests/checking/typing/lambda_typed.move:81:12
-   │
-81 │         f: |u64|u64, // expected lambda not allowed
-   │            ^^^^^^^^
-   │
-   = required by declaration of field `f`

third_party/move/move-compiler-v2/tests/lambda/inline-parity/subtype_args.lambda.exp

@@ -532,13 +532,13 @@ module 0x8675309::M {
 
 
 Diagnostics:
-error: Calls to function values other than inline function parameters not yet supported
+error: Calls to function values other than inline function parameters not yet implemented
    ┌─ tests/lambda/inline-parity/subtype_args.move:24:9
    │
 24 │         f(&mut 0, &mut 0);
    │         ^^^^^^^^^^^^^^^^^
 
-error: Calls to function values other than inline function parameters not yet supported
+error: Calls to function values other than inline function parameters not yet implemented
    ┌─ tests/lambda/inline-parity/subtype_args.move:25:9
    │
 25 │         f(&0, &mut 0);

third_party/move/move-compiler-v2/tests/lambda/lambda.exp

@@ -48,11 +48,3 @@ error: tuple type `()` is not allowed as a type argument (type was inferred)
    │                                     ^
    │
    = required by instantiating type parameter `T` of function `foreach`
-
-error: function type `|u64|u64` is not allowed as a field type
-   ┌─ tests/lambda/lambda.move:81:12
-   │
-81 │         f: |u64|u64, // expected lambda not allowed
-   │            ^^^^^^^^
-   │
-   = required by declaration of field `f`

third_party/move/move-compiler-v2/tests/lambda/lambda.lambda.exp

@@ -48,11 +48,3 @@ error: tuple type `()` is not allowed as a type argument (type was inferred)
    │                                     ^
    │
    = required by instantiating type parameter `T` of function `foreach`
-
-error: function type `|u64|u64` is not allowed as a field type
-   ┌─ tests/lambda/lambda.move:81:12
-   │
-81 │         f: |u64|u64, // expected lambda not allowed
-   │            ^^^^^^^^
-   │
-   = required by declaration of field `f`

third_party/move/move-compiler-v2/tests/lambda/lambda4.lambda.exp

@@ -177,7 +177,7 @@ public fun M::fun_result_lambda_not_allowed(): |u64| {
 
 
 Diagnostics:
-error: Unexpected type: |u64|
+error: Unimplemented type: |u64|
    ┌─ tests/lambda/lambda4.move:89:16
    │
 89 │     public fun fun_result_lambda_not_allowed(): |u64| {  // expected lambda not allowed