Fix YulLabel parsing (#1185)

Change the order that YulStatements get parsed so that
`YulVariableAssignmentStatement` gets tried before `YulLabel`. This
prevents and issue pre-0.5.0 where an assignment statement like this:

```solidity
assembly {
    foo:  = mload(0x80)
}
```

would get parsed as a label and then everything from `=` on would cause
an error. Now for versions before 0.5.5 this gets correctly parsed as a
variable assignment.

Closes #1182

---------

Co-authored-by: Omar Tawfik <[email protected]>

crates/solidity/inputs/language/src/definition.rs

@@ -4178,9 +4178,9 @@ codegen_language_macros::compile!(Language(
                                 EnumVariant(reference = YulLeaveStatement, enabled = From("0.6.0")),
                                 EnumVariant(reference = YulBreakStatement),
                                 EnumVariant(reference = YulContinueStatement),
+                                EnumVariant(reference = YulVariableAssignmentStatement),
                                 EnumVariant(reference = YulLabel, enabled = Till("0.5.0")),
                                 EnumVariant(reference = YulVariableDeclarationStatement),
-                                EnumVariant(reference = YulVariableAssignmentStatement),
                                 EnumVariant(reference = YulExpression)
                             ]
                         ),

crates/solidity/testing/snapshots/cst_output/YulStatement/label/generated/0.4.11-success.yml

@@ -0,0 +1,12 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+Source: >
+  1  │ foo_label:                                                                       │ 0..10
+
+Errors: []
+
+Tree:
+  - (YulStatement) ► (variant꞉ YulLabel): # "foo_label:\n" (0..11)
+      - (label꞉ YulIdentifier): "foo_label" # (0..9)
+      - (colon꞉ Colon): ":" # (9..10)
+      - (trailing_trivia꞉ EndOfLine): "\n" # (10..11)

crates/solidity/testing/snapshots/cst_output/YulStatement/label/generated/0.5.0-failure.yml

@@ -0,0 +1,20 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+Source: >
+  1  │ foo_label:                                                                       │ 0..10
+
+Errors: # 1 total
+  - >
+    Error: Expected OpenParen.
+       ╭─[crates/solidity/testing/snapshots/cst_output/YulStatement/label/input.sol:1:10]
+       │
+     1 │ foo_label:
+       │          ─┬  
+       │           ╰── Error occurred here.
+    ───╯
+
+Tree:
+  - (YulStatement): # "foo_label:\n" (0..11)
+      - (variant꞉ YulExpression) ► (variant꞉ YulPath): # "foo_label" (0..9)
+          - (item꞉ YulIdentifier): "foo_label" # (0..9)
+      - (UNRECOGNIZED): ":\n" # (9..11)

crates/solidity/testing/snapshots/cst_output/YulStatement/label/input.sol

@@ -0,0 +1 @@
+foo_label:

crates/solidity/testing/snapshots/cst_output/YulStatement/var_assign_colon_and_equals/generated/0.4.11-success.yml

@@ -0,0 +1,28 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+Source: >
+  1  │ // Makes sure that `newB:` is not parsed as a label here, and that we continue parsing to get a whole assignment statement. │ 0..123
+  2  │ newB: = mload(0x80)                                                                                                         │ 124..143
+
+Errors: []
+
+Tree:
+  - (YulStatement) ► (variant꞉ YulVariableAssignmentStatement): # "// Makes sure that `newB:` is not parsed as a labe..." (0..144)
+      - (variables꞉ YulPaths): # "// Makes sure that `newB:` is not parsed as a labe..." (0..128)
+          - (item꞉ YulPath): # "// Makes sure that `newB:` is not parsed as a labe..." (0..128)
+              - (leading_trivia꞉ SingleLineComment): "// Makes sure that `newB:` is not parsed as a labe..." # (0..123)
+              - (leading_trivia꞉ EndOfLine): "\n" # (123..124)
+              - (item꞉ YulIdentifier): "newB" # (124..128)
+      - (assignment꞉ YulAssignmentOperator) ► (variant꞉ YulColonAndEqual): # ": =" (128..131)
+          - (colon꞉ Colon): ":" # (128..129)
+          - (leading_trivia꞉ Whitespace): " " # (129..130)
+          - (equal꞉ Equal): "=" # (130..131)
+      - (expression꞉ YulExpression) ► (variant꞉ YulFunctionCallExpression): # " mload(0x80)\n" (131..144)
+          - (operand꞉ YulExpression) ► (variant꞉ YulBuiltInFunction): # " mload" (131..137)
+              - (leading_trivia꞉ Whitespace): " " # (131..132)
+              - (variant꞉ YulMLoadKeyword): "mload" # (132..137)
+          - (open_paren꞉ OpenParen): "(" # (137..138)
+          - (arguments꞉ YulArguments): # "0x80" (138..142)
+              - (item꞉ YulExpression) ► (variant꞉ YulLiteral) ► (variant꞉ YulHexLiteral): "0x80" # (138..142)
+          - (close_paren꞉ CloseParen): ")" # (142..143)
+          - (trailing_trivia꞉ EndOfLine): "\n" # (143..144)

crates/solidity/testing/snapshots/cst_output/YulStatement/var_assign_colon_and_equals/generated/0.5.5-failure.yml

@@ -0,0 +1,23 @@
+# This file is generated automatically by infrastructure scripts. Please don't edit by hand.
+
+Source: >
+  1  │ // Makes sure that `newB:` is not parsed as a label here, and that we continue parsing to get a whole assignment statement. │ 0..123
+  2  │ newB: = mload(0x80)                                                                                                         │ 124..143
+
+Errors: # 1 total
+  - >
+    Error: Expected OpenParen.
+       ╭─[crates/solidity/testing/snapshots/cst_output/YulStatement/var_assign_colon_and_equals/input.sol:2:5]
+       │
+     2 │ newB: = mload(0x80)
+       │     ────────┬───────  
+       │             ╰───────── Error occurred here.
+    ───╯
+
+Tree:
+  - (YulStatement): # "// Makes sure that `newB:` is not parsed as a labe..." (0..144)
+      - (variant꞉ YulExpression) ► (variant꞉ YulPath): # "// Makes sure that `newB:` is not parsed as a labe..." (0..128)
+          - (leading_trivia꞉ SingleLineComment): "// Makes sure that `newB:` is not parsed as a labe..." # (0..123)
+          - (leading_trivia꞉ EndOfLine): "\n" # (123..124)
+          - (item꞉ YulIdentifier): "newB" # (124..128)
+      - (UNRECOGNIZED): ": = mload(0x80)\n" # (128..144)

crates/solidity/testing/snapshots/cst_output/YulStatement/var_assign_colon_and_equals/input.sol

@@ -0,0 +1,2 @@
+// Makes sure that `newB:` is not parsed as a label here, and that we continue parsing to get a whole assignment statement.
+newB: = mload(0x80)