Enhance WHILE and IF validation failure messages.

atest/robot/running/while/while_limit.robot

@@ -56,4 +56,4 @@ Limit used multiple times
 
 Invalid values after limit
     ${tc} =    Check Test Case    ${TESTNAME}
-    Should Be Equal    ${tc.body[0].condition}    $variable < 2, limit=-1x, invalid, values
+    Should Be Equal    ${tc.body[0].condition}    $variable < 2, limit=2, invalid

atest/testdata/running/if/invalid_if.robot

@@ -69,7 +69,6 @@ Recommend $var syntax if invalid condition contains ${var}
         Fail    Shouldn't be run
     END
 
-
 IF without END
     [Documentation]    FAIL    IF must have closing END.
     IF    ${True}
@@ -98,7 +97,7 @@ ELSE IF without condition
     END
 
 ELSE IF with multiple conditions
-    [Documentation]    FAIL    ELSE IF cannot have more than one condition.
+    [Documentation]    FAIL    ELSE IF cannot have more than one condition, got '\${False}', 'ooops' and '\${True}'.
     IF    'maa' == 'maa'
         Fail    Should not be run
     ELSE IF    ${False}    ooops    ${True}
@@ -216,16 +215,16 @@ Multiple errors
     ...    - ELSE IF not allowed after ELSE.
     ...    - Only one ELSE allowed.
     ...    - IF must have closing END.
-    ...    - ELSE IF cannot have more than one condition.
+    ...    - ELSE IF cannot have more than one condition, got 'too' and 'many'.
     ...    - ELSE IF branch cannot be empty.
-    ...    - ELSE does not accept arguments, got 'oops'.
+    ...    - ELSE does not accept arguments, got 'oops', 'i', 'did', 'it' and 'again'.
     ...    - ELSE branch cannot be empty.
     ...    - ELSE IF must have a condition.
     ...    - ELSE IF branch cannot be empty.
     ...    - ELSE branch cannot be empty.
     IF
     ELSE IF    too    many
-    ELSE    oops
+    ELSE    oops    i    did    it    again
     ELSE IF
     ELSE
 

atest/testdata/running/while/invalid_while.robot

@@ -1,33 +1,33 @@
 *** Test Cases ***
 Multiple conditions
-    [Documentation]    FAIL    WHILE cannot have more than one condition, got 'Too', 'many', 'conditions' and '!'.
+    [Documentation]    FAIL    WHILE loop cannot have more than one condition, got 'Too', 'many', 'conditions' and '!'.
     WHILE    Too    many    conditions    !
         Fail    Not executed!
     END
 
 Invalid condition
-    [Documentation]    FAIL    Invalid WHILE condition: \
+    [Documentation]    FAIL    Invalid WHILE loop condition: \
     ...    Evaluating expression 'bad' failed: NameError: name 'bad' is not defined nor importable as module
     WHILE    bad
         Fail    Not executed!
     END
 
 Non-existing ${variable} in condition
-    [Documentation]    FAIL    Invalid WHILE condition: \
+    [Documentation]    FAIL    Invalid WHILE loop condition: \
     ...    Evaluating expression '\${bad} > 0' failed: Variable '\${bad}' not found.
     WHILE    ${bad} > 0
         Fail    Not executed!
     END
 
 Non-existing $variable in condition
-    [Documentation]    FAIL    Invalid WHILE condition: \
+    [Documentation]    FAIL    Invalid WHILE loop condition: \
     ...    Evaluating expression '$bad > 0' failed: Variable '$bad' not found.
     WHILE    $bad > 0
         Fail    Not executed!
     END
 
 Recommend $var syntax if invalid condition contains ${var}
-    [Documentation]    FAIL    Invalid WHILE condition: \
+    [Documentation]    FAIL    Invalid WHILE loop condition: \
     ...    Evaluating expression 'x == 'x'' failed: NameError: name 'x' is not defined nor importable as module
     ...
     ...    Variables in the original expression '\${x} == 'x'' were resolved before the expression was evaluated. \
@@ -38,7 +38,7 @@ Recommend $var syntax if invalid condition contains ${var}
     END
 
 Invalid condition on second round
-    [Documentation]    FAIL    Invalid WHILE condition: \
+    [Documentation]    FAIL    Invalid WHILE loop condition: \
     ...    Evaluating expression 'bad' failed: NameError: name 'bad' is not defined nor importable as module
     ...
     ...    Variables in the original expression '\${condition}' were resolved before the expression was evaluated. \
@@ -76,7 +76,7 @@ Invalid condition causes normal error
         WHILE    bad
             Fail    Should not be run
         END
-    EXCEPT    Invalid WHILE condition: Evaluating expression 'bad' failed: NameError: name 'bad' is not defined nor importable as module
+    EXCEPT    Invalid WHILE loop condition: Evaluating expression 'bad' failed: NameError: name 'bad' is not defined nor importable as module
         No Operation
     END
 
@@ -85,6 +85,6 @@ Non-existing variable in condition causes normal error
         WHILE    ${bad}
             Fail    Should not be run
         END
-    EXCEPT    Invalid WHILE condition: Evaluating expression '\${bad}' failed: Variable '\${bad}' not found.
+    EXCEPT    Invalid WHILE loop condition: Evaluating expression '\${bad}' failed: Variable '\${bad}' not found.
         No Operation
     END

atest/testdata/running/while/on_limit.robot

@@ -67,7 +67,7 @@ Invalid on_limit
     END
 
 On limit without limit defined
-    [Documentation]    FAIL WHILE on_limit option cannot be used without limit.
+    [Documentation]    FAIL WHILE loop 'on_limit' option cannot be used without 'limit'.
     WHILE    True    on_limit=PaSS
         No Operation
     END
@@ -85,7 +85,7 @@ On limit message without limit
     END
 
 Wrong WHILE argument
-    [Documentation]     FAIL WHILE cannot have more than one condition, got '$variable < 2', 'limit=5' and 'limit_exceed_messag=Custom error message'.
+    [Documentation]     FAIL WHILE loop cannot have more than one condition, got '$variable < 2', 'limit=5' and 'limit_exceed_messag=Custom error message'.
     WHILE    $variable < 2    limit=5    limit_exceed_messag=Custom error message
         Log     ${variable}
     END
@@ -135,7 +135,7 @@ On limit message with invalid variable
     END
 
 Wrong WHILE arguments
-    [Documentation]     FAIL WHILE cannot have more than one condition, got '$variable < 2', 'limite=5' and 'limit_exceed_messag=Custom error message'.
+    [Documentation]     FAIL WHILE loop cannot have more than one condition, got '$variable < 2', 'limite=5' and 'limit_exceed_messag=Custom error message'.
     WHILE    $variable < 2    limite=5    limit_exceed_messag=Custom error message
         Log     ${variable}
     END

atest/testdata/running/while/while_limit.robot

@@ -100,8 +100,8 @@ Invalid limit invalid value
     END
 
 Invalid limit mistyped prefix
-    [Documentation]     FAIL WHILE cannot have more than one condition, got '$variable < 2' and 'limitation=-1x'.
-    WHILE    $variable < 2    limitation=-1x
+    [Documentation]     FAIL WHILE loop cannot have more than one condition, got '$variable < 2' and 'limitation=2'.
+    WHILE    $variable < 2    limitation=2
         Log     ${variable}
     END
 
@@ -112,8 +112,8 @@ Limit used multiple times
     END
 
 Invalid values after limit
-    [Documentation]     FAIL WHILE cannot have more than one condition, got '$variable < 2', 'limit=-1x', 'invalid' and 'values'.
-    WHILE    $variable < 2    limit=-1x    invalid    values
+    [Documentation]     FAIL WHILE loop cannot have more than one condition, got '$variable < 2', 'limit=2' and 'invalid'.
+    WHILE    $variable < 2    limit=2    invalid
         Log     ${variable}
     END
 

src/robot/parsing/model/statements.py

@@ -980,11 +980,12 @@ def assign(self) -> 'tuple[str, ...]':
         return self.get_values(Token.ASSIGN)
 
     def validate(self, ctx: 'ValidationContext'):
-        conditions = len(self.get_tokens(Token.ARGUMENT))
-        if conditions == 0:
+        conditions = self.get_tokens(Token.ARGUMENT)
+        if not conditions:
             self.errors += (f'{self.type} must have a condition.',)
-        if conditions > 1:
-            self.errors += (f'{self.type} cannot have more than one condition.',)
+        if len(conditions) > 1:
+            self.errors += (f'{self.type} cannot have more than one condition, '
+                            f'got {seq2str(c.value for c in conditions)}.',)
 
 
 @Statement.register
@@ -1181,13 +1182,17 @@ def on_limit_message(self) -> 'str|None':
         return self.get_option('on_limit_message')
 
     def validate(self, ctx: 'ValidationContext'):
-        values = self.get_values(Token.ARGUMENT)
-        if len(values) > 1:
-            self.errors += (f'WHILE cannot have more than one condition, got {seq2str(values)}.',)
+        conditions = self.get_tokens(Token.ARGUMENT)
+        if len(conditions) > 1:
+            self._add_error(f'cannot have more than one condition, got '
+                            f'{seq2str(c.value for c in conditions)}')
         if self.on_limit and not self.limit:
-            self.errors += ('WHILE on_limit option cannot be used without limit.',)
+            self._add_error("'on_limit' option cannot be used without 'limit'")
         self._validate_options()
 
+    def _add_error(self, error: str):
+        self.errors += (f'WHILE loop {error}.',)
+
 
 @Statement.register
 class ReturnStatement(Statement):

src/robot/running/bodyrunner.py

@@ -439,7 +439,7 @@ def _should_run(self, condition, variables):
                                        resolve_variables=True)
         except Exception:
             msg = get_error_message()
-            raise DataError(f'Invalid WHILE condition: {msg}')
+            raise DataError(f'Invalid WHILE loop condition: {msg}')
 
 
 class IfRunner:

utest/parsing/test_model.py

@@ -441,7 +441,8 @@ def test_invalid(self):
                         Token(Token.ARGUMENT, 'many', 3, 20),
                         Token(Token.ARGUMENT, 'values', 3, 28),
                         Token(Token.ARGUMENT, '!', 3, 38)],
-                errors=('WHILE cannot have more than one condition, got \'too\', \'many\', \'values\' and \'!\'.',)
+                errors=("WHILE loop cannot have more than one condition, "
+                        "got 'too', 'many', 'values' and '!'.",)
             ),
             end=End([
                 Token(Token.END, 'END', 5, 4)