lang: Fix account try_from usage

lang/src/lib.rs

@@ -393,9 +393,10 @@ pub mod prelude {
         context::Context, context::CpiContext, declare_id, emit, err, error, event, program,
         require, require_eq, require_gt, require_gte, require_keys_eq, require_keys_neq,
         require_neq, solana_program::bpf_loader_upgradeable::UpgradeableLoaderState, source,
-        system_program::System, zero_copy, AccountDeserialize, AccountSerialize, Accounts,
-        AccountsClose, AccountsExit, AnchorDeserialize, AnchorSerialize, Id, InitSpace, Key,
-        Lamports, Owner, ProgramData, Result, Space, ToAccountInfo, ToAccountInfos, ToAccountMetas,
+        system_program::System, try_from, zero_copy, AccountDeserialize, AccountSerialize,
+        Accounts, AccountsClose, AccountsExit, AnchorDeserialize, AnchorSerialize, Id, InitSpace,
+        Key, Lamports, Owner, ProgramData, Result, Space, ToAccountInfo, ToAccountInfos,
+        ToAccountMetas,
     };
     pub use anchor_attribute_error::*;
     pub use borsh;
@@ -727,3 +728,10 @@ macro_rules! source {
         }
     };
 }
+
+#[macro_export]
+macro_rules! try_from {
+    ($ty: ty, $acc: expr) => {
+        <$ty>::try_from(unsafe { core::mem::transmute::<_, &AccountInfo<'_>>($acc.as_ref()) })
+    };
+}

tests/misc/Anchor.toml

@@ -9,6 +9,7 @@ misc = "3TEqcc8xhrhdspwbvoamUJe2borm4Nr72JxL66k6rgrh"
 misc_optional = "FNqz6pqLAwvMSds2FYjR4nKV3moVpPNtvkfGFrqLKrgG"
 overflow_checks = "overf1owChecks11111111111111111111111111111"
 remaining_accounts = "RemainingAccounts11111111111111111111111111"
+try_from = "TryFrom111111111111111111111111111111111111"
 
 [workspace]
 exclude = ["programs/shared"]

tests/misc/programs/try-from/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "try-from"
+version = "0.1.0"
+description = "Created with Anchor"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "try_from"
+
+[features]
+no-entrypoint = []
+no-idl = []
+no-log-ix-name = []
+cpi = ["no-entrypoint"]
+default = []
+
+[dependencies]
+anchor-lang = { path = "../../../../lang" }

tests/misc/programs/try-from/Xargo.toml

@@ -0,0 +1,2 @@
+[target.bpfel-unknown-unknown.dependencies.std]
+features = []

tests/misc/programs/try-from/src/lib.rs

@@ -0,0 +1,40 @@
+use anchor_lang::prelude::*;
+
+declare_id!("TryFrom111111111111111111111111111111111111");
+
+#[program]
+pub mod try_from {
+    use super::*;
+
+    pub fn init(ctx: Context<Init>, field: u8) -> Result<()> {
+        ctx.accounts.my_account.field = field;
+        Ok(())
+    }
+
+    pub fn try_from(ctx: Context<TryFrom>, field: u8) -> Result<()> {
+        let my_account = try_from!(Account::<MyAccount>, ctx.accounts.my_account)?;
+        msg!("Field: {}", my_account.field);
+        require_eq!(my_account.field, field);
+
+        Ok(())
+    }
+}
+
+#[derive(Accounts)]
+pub struct Init<'info> {
+    #[account(init, payer = payer, space = 8 + 1)]
+    pub my_account: Account<'info, MyAccount>,
+    #[account(mut)]
+    pub payer: Signer<'info>,
+    pub system_program: Program<'info, System>,
+}
+
+#[derive(Accounts)]
+pub struct TryFrom<'info> {
+    pub my_account: UncheckedAccount<'info>,
+}
+
+#[account]
+pub struct MyAccount {
+    pub field: u8,
+}

tests/misc/tests/try-from/Test.toml

@@ -0,0 +1,2 @@
+[scripts]
+test = "yarn run ts-mocha -t 1000000 ./tests/try-from/*.ts"

tests/misc/tests/try-from/try-from.ts

@@ -0,0 +1,28 @@
+import * as anchor from "@coral-xyz/anchor";
+
+import { TryFrom, IDL } from "../../target/types/try_from";
+
+describe(IDL.name, () => {
+  anchor.setProvider(anchor.AnchorProvider.env());
+
+  const program = anchor.workspace.TryFrom as anchor.Program<TryFrom>;
+
+  it("Can use `try_from`", async () => {
+    const myAccountKp = anchor.web3.Keypair.generate();
+    const FIELD = 5;
+    await program.methods
+      .init(FIELD)
+      .accounts({
+        myAccount: myAccountKp.publicKey,
+      })
+      .signers([myAccountKp])
+      .rpc();
+
+    await program.methods
+      .tryFrom(FIELD)
+      .accounts({
+        myAccount: myAccountKp.publicKey,
+      })
+      .rpc();
+  });
+});