syntax: Reject semver version individual parts in strings

liblangutil/SemVerHandler.cpp

@@ -240,6 +240,8 @@ SemVerMatchExpression::MatchComponent SemVerMatchExpressionParser::parseMatchCom
 		component.prefix = Token::Assign;
 	}
 
+	auto const partsStartPos = m_pos;
+
 	component.levelsPresent = 0;
 	while (component.levelsPresent < 3)
 	{
@@ -250,6 +252,18 @@ SemVerMatchExpression::MatchComponent SemVerMatchExpressionParser::parseMatchCom
 		else
 			break;
 	}
+
+	// Validate that the parsed version parts are either a single string literal or multiple bare tokens,
+	// i.e. "1.2.3" or 1.2.3 but not 1."2.3", "1".2.3 or 1"."2.3.
+	auto const partsEndPos = m_pos; // Points *after* the last version part
+	for (auto i = partsStartPos; i < partsEndPos; ++i)
+	{
+		if (m_tokens[i] == Token::StringLiteral && partsStartPos != partsEndPos - 1)
+		{
+			solThrow(SemVerError, "String literals are only allowed as the only component in a version pragma.");
+		}
+	}
+
 	// TODO we do not support pre and build version qualifiers for now in match expressions
 	// (but we do support them in the actual versions)
 	return component;

libsolidity/ast/AST.h

@@ -312,7 +312,7 @@ class Declaration: public ASTNode, public Scopable
 };
 
 /**
- * Pragma directive, only version requirements in the form `pragma solidity "^0.4.0";` are
+ * Pragma directive, only version requirements in the form `pragma solidity ^"0.4.0";` are
  * supported for now.
  */
 class PragmaDirective: public ASTNode

test/libsolidity/syntaxTests/pragma/broken_version_strings_digit.sol

@@ -0,0 +1,3 @@
+pragma solidity ^"0"."8"."2";
+// ----
+// ParserError 1684: (0-29): Invalid version pragma. String literals are only allowed as the only component in a version pragma.

test/libsolidity/syntaxTests/pragma/broken_version_strings_dots.sol

@@ -0,0 +1,3 @@
+pragma solidity ^ 0 "." 8 "." 2;
+// ----
+// ParserError 1684: (0-32): Invalid version pragma. String literals are only allowed as the only component in a version pragma.

test/libsolidity/syntaxTests/pragma/broken_version_strings_part.sol

@@ -0,0 +1,3 @@
+pragma solidity ^ 0."8.0";
+// ----
+// ParserError 1684: (0-26): Invalid version pragma. String literals are only allowed as the only component in a version pragma.

test/libsolidity/syntaxTests/pragma/broken_version_strings_prefix.sol

@@ -0,0 +1,3 @@
+pragma solidity "^0.8.0";
+// ----
+// ParserError 1684: (0-25): Invalid version pragma. Expected the start of a version number but instead found character '^'. Version number is invalid or the pragma is not terminated with a semicolon.

test/libsolidity/syntaxTests/pragma/version_component_string_mixed.sol

@@ -0,0 +1 @@
+pragma solidity >= 0.0 <= "123456";

test/libsolidity/syntaxTests/pragma/version_component_string_prefix.sol

@@ -0,0 +1 @@
+pragma solidity <= "123456";